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Preface to the second

edition

Over the last five years echocardiography as a specialty has evolved

dramatically. When the first edition of this book was published, people

were still exploring the potential for clinical uses of 3D echocardiography,

new echocardiography-guided transcatheter interventions were being

evaluated, and routine use of echocardiography in the intensive care and

emergency departments was being considered. All of these developments

are now sufficiently established in day-to-day clinical practice to warrant

inclusion in this essential handbook-guide on how to perform echo-

cardiography.

Importantly, all the basics still form the bulk of the new handbook, so that

even the complete novice can pick up the text and start to learn how to

acquire good quality images and interpret what they see. These sections

have now been enhanced with colour images and video loops as well as

having been reviewed to ensure the information is consistent with numer-

ous new guidelines released by international echocardiography societies.

We are delighted with the success and widespread appeal of this hand-

book. When we wrote the first edition, however, we did not expect to

have to update so much, so soon. This is a reflection of how rapidly

echocardiography as a specialty develops and has allowed us to produce

an even better echocardiography handbook. We hope you enjoy it.

ARJM

2012

Preface to the first edition

Why another book on echocardiography? There are numerous textbooks,

some with excellent descriptions, accompanied by images of normal and

abnormal findings.

This handbook originates from the demands of our trainees and sonogra-

phers for a new approach based on practical guidelines that describe how

to apply current imaging technology to address the common, key issues

in adult echocardiography. The book follows the natural workflow of

echocardiography, detailing what to record, and how to analyse and report

studies. These demands have also been heard by the professional organiza-

tions like the British and American Society of Echocardiography and the

European Association of Echocardiography who have started to provide

guidelines for specific questions. Therefore this handbook combines the

standard acquisition protocols, analysis and reporting for adult transtho-

racic and transoesophageal echocardiography, starting from a minimal

recording dataset, with all the current guidelines relevant to clinical

practice.

The book was designed as a comprehensive compendium of focused

approaches for specific clinical questions. We hope it will be used both

as a means to learn how to perform echocardiography and as a trusted,

easily accessible reference for those who are already proficient.

Contributors

We would like to express our sincere thanks to the contributors to the

original edition and the following people for their expert contributions

and advice that were used as the basis for the following sections in the

new edition (in alphabetical order):

Harald Becher

Jonathan Goldman

Professor of Cardiology,

Consultant Cardiologist, VA

Mazankowski Alberta Heart

Hospital, San Francisco, CA, USA

Institute,

Chapter 4: Left atrial measures

University of Alberta, Edmonton,

Lucy Hudsmith

Canada

Chapters 4 and 7: 3D left

Consultant Cardiologist in Adult

ventricular and right ventricular

Congenital Heart Disease,

function

The Queen Elizabeth Hospital,

Chapter 9: Contrast

Birmingham, UK

echocardiography

Chapters 3, 4, 6, and 7: Tricuspid

valve, Pulmonary valve, and

Will Bradlow

Congenital heart disease

Specialist Trainee in Cardiology,

Xu Yu Jin

John Radcliffe Hospital, Oxford,

Consultant in Surgical Echo-Cardi-

Chapters 4 and 7: 2D right

ology, John Radcliffe Hospital,

ventricular function

Oxford, UK

Chapter 5: Intraoperative

John Chambers

transoesophageal echocardiography

Consultant Cardiologist,

Cardiothoracic Centre, Guy’s and

Theodoros Karamitsos

St. Thomas’ Hospital, London, UK

Honorary Consultant Cardiologist

Chapter 3: Aortic stenosis

and University

Research Lecturer,

Jonathan Choy

John Radcliffe Hospital and

Cardiologist & University of

University of Oxford, UK

Alberta Echo Lab Director,

Chapter 10: Stress

University of Alberta, Edmonton,

echocardiography

Canada

Justin Mandeville

Chapter 4: 3D left ventricular

function

Senior Critical Care Echo Fellow,

John Radcliffe Hospital,

Claire Colebourn

Oxford, UK

Consultant Intensivist, Programme

Chapter 11: Acute echocardiography

Lead Oxford Critical Care Echo

Fellowship, John Radcliffe Hospital,

Oxford, UK

Chapter 11: Acute echocardiography

CONTRIBUTORS

Thomas Marwick

Susanna Price

Director, Center for

Consultant Cardiologist and

Cardiovascular Imaging, Heart and

Intensivist, Royal Brompton &

Vascular Institute, Cleveland

Harefield NHS Foundation Trust,

Clinic, Cleveland, OH, USA

London, UK

Chapter 4: Left ventricular function

Andrew R.J. Mitchell

Oliver Rider

Consultant Cardiologist,

Clinical Lecturer Cardiovascular

General Hospital, St. Helier,

Medicine, John Radcliffe Hospital,

Jersey, Channel Islands, UK

Oxford, UK

Chapter 8: Intracardiac

Chapter 1: Ultrasound

echocardiography

Michael Stewart

Saul Myerson

Consultant Cardiologist,

Consultant Cardiologist, John

Cardiothoracic Unit, The James

Radcliffe Hospital, Honorary

Cook University Hospital,

Senior Clinical Lecturer, University

Middlesborough, UK

of Oxford, UK

Chapters 4 and 7: Aorta

Chapters 3 and 6: Aortic

regurgitation

Jon Timperley

Consultant Cardiologist,

Jim Newton

Northampton General Hospital,

Consultant Cardiologist, John

Northampton, UK

Radcliffe Hospital, Oxford, UK

Chapters 3 and 6: Mitral stenosis

Chapters 3 and 6: 3D TOE

and mitral regurgitation

prosthetic valvular assessment and

James Willis

Transcatheter aortic valve

implantation

Research Cardiac Physiologist,

Royal United Hospital, Bath, and

Steffen Petersen

University of Bath, UK

Honorary Consultant Cardiologist,

DVD

Centre Lead for Advanced

Cardiovascular Imaging, Barts and

The London NIHR Biomedical

Research Unit, The London Chest

Hospital, London, UK

Chapter 4: Cardiomyopathies

This new edition was compiled and revised by Paul Leeson and Daniel

Augustine. The text was illustrated by Paul Leeson and Daniel Augustine.

Paul Leeson, Daniel Augustine, Andrew Mitchell, and Harald Becher edited

the final version.

Symbols and abbreviations

cross-reference

approximately

two-dimensional

three-dimensional

A-wave velocity

A4C

apical 4-chamber

aorta

aortic regurgitation

aortic stenosis

ASD

atrial septal defect

aortic valve

BSA

body surface area

CFM

colour flow mapping

CHD

congenital heart disease

CMR

cardiovascular magnetic resonance

cardiac output

CRT

cardiac resynchronization therapy

CSA

cross-sectional area

computed tomography

continuous wave (Doppler)

diastole

DET

deceleration time

E-wave velocity

ECG

electrocardiogram

end-diastole

ejection fraction

EROA

effective regurgitant orifice area

HFNEF

heart failure with a normal ejection fraction

hertz

ICE

intracardiac echocardiography

IVC

inferior vena cava

IVRT

isovolumetric relaxation time

JVP

jugular venous pressure

left atrium

LLPV

left lower pulmonary vein

LUPV

left upper pulmonary vein

xii

SYMBOLS AND ABBREVIATIONS

left ventricle

LVID

left ventricular internal diameter

LVOT

left ventricular outflow tract

LVPW

left ventricular posterior wall

LVS

left ventricular septum

MHz

megahertz

MPR

multiplanar reformatting

mitral regurgitation

mitral stenosis

mitral valve

MVA

mitral valve area

pulmonary artery

PDA

patent ductus arteriosus

PFO

patent foramen ovale

PISA

proximal isovelocity surface area

PLAX

parasternal long axis view

pulmonary regurgitation

PRF

pulse repetition frequency

pulmonary stenosis

PSAX

parasternal short axis view

pulmonary valve

pulse wave (Doppler)

right atrium

RLPV

right lower pulmonary vein

RUPV

right upper pulmonary vein

right ventricle

RVOT

right ventricular outflow tract

systole

SAX

short axis

stroke volume

SVC

superior vena cava

TAVI

transcatheter aortic valve implantation

TGC

time-gain compensation

TOE

transoesophageal echocardiography

tricuspid regurgitation

TTE

transthoracic echocardiography

tricuspid valve

volt/s

VSD

ventricular septal defect

vti

velocity time integral

xiii

References

Reference Textbooks (alphabetical order)

Feigenbaum H (2004). Echocardiography 6^th edition. Philadelphia,

PA: Lippincott, Williams & Wilkins.

Galiuto L, Badano L, Fox K, Sicari R, Zamorano J (2011). The EAE

Textbook of Echocardiography. Oxford: Oxford University Press.

Otto CM (2004). Textbook of Clinical Echocardiography, 3^rd edition.

WB Saunders and Co Ltd.

Perrino AC, Reeves ST (2007). A Practical Approach to Transesophageal

Echocardiography 2^nd edition. Philadelphia, PA: Lippincott, Williams &

Wilkins.

Rimmington H, Chambers J (2007). Echocardiography: Guidelines for

Reporting—A Practical Handbook, 2^nd edition. New York: Informa

Healthcare.

Sidebotham D, Merry A, Legget M, Bashein G (2003). Practical

Perioperative Transoesophageal Echocardiography. Philadelphia,

PA: Butterworth-Heinemann Ltd.

Zamorano J, Bax J, Rademakers F, Knuuti F (2009). The ESC Textbook of

Cadiovascular Imaging. Boston, MA: Springer.

Websites

- American Heart Association M http://www.americanheart.org

- American Society of Echocardiography M http://www.asecho.org

- British Cardiovascular Society M http://www.bcs.com

- British Heart Foundation M http://www.bhf.org.uk

- British Society of Echocardiography M http://www.bsecho.org

- European Association of Echocardiography M http://www.escardio.

org/bodies/associations/EAE

- European Society of Cardiology M http://www.escardio.org

Papers and guidelines

Lancellotti P, Tribouilloy C, Hagendorff A, et al. European Association of

Echocardiography recommendations for the assessment of valvular

regurgitation. Part 1: aortic and pulmonary regurgitation (native valve

disease). European Journal of Echocardiography 2010; 11:223–44.

Rudski L, Lai W, Afilalo J, et al. Guidelines for the echocardiographic

assessment of the right heart in adults: a report from the American

Society of Echocardiography endorsed by the European Association of

Echocardiography. J Am Soc Echocardiogr 2010; 23:685–713.

xiv

REFERENCES

Aune E, Baekkevar M, Rodevand O, et al. Reference values for left

ventricular volumes with real time 3 dimensional echocardiography.

Scandinavian Cardiovascular Journal 2010; 44:24–30.

Horton K, Meece R, Hill J. Assessment of the right ventricle by

echocardiography: a primer for cardiac sonographers. J Am Soc

Echocardiogr 2009; 7:776–92.

Saito K, Okura H, Watanabe N, et al. Comprehensive evaluation of left

ventricular strain using speckle tracking echocardiography in normal

adults: comparison of three dimensional and two dimensional

approaches. J Am Soc Echocardiogr 2009; 22(9):1025–30.

Recommendations for evaluation of the severity of native valvular

regurgitation with two-dimensional and Doppler echocardiography.

A report from the American Society of Echocardiography’s

Nomenclature and Standards Committee and The Task Force on

Valvular Regurgitation, developed in conjunction with the American

College of Cardiology Echocardiography Committee, The Cardiac

Imaging Committee Council on Clinical Cardiology, the American Heart

Association, and the European Society of Cardiology Working Group on

Echocardiography. J Am Soc Echocardiogr 2003; 16:777–802.

Recommendations for chamber quantification: a report of the American

Society of Echocardiography Guidelines and Standards Committee and

the Chamber Quantification Writing Group, developed in conjunction

with the European Association of Echocardiography.

J Am Soc Echocardiogr 2005; 18:1440–63.

Waggoner AD, Ehler D, Adams D, et al. Guidelines for the cardiac

sonographer in the performance of contrast echocardiography:

recommendations of the American Society of Echocardiography.

J Am Soc Echocardiogr 2001; 14:417–20.

Masani N, Chambers J, Hancock J, et al. BSE Echocardiogram Report:

Recommendations for Standard Adult Transthoracic Echocardiography.

From the British Society of Echocardiography Education Committee.

Becher H, Chambers J, Fox K, et al. British Society of Echocardiography

Policy Committee. BSE procedure guidelines for the clinical application

of stress echocardiography, recommendations for performance and

interpretation of stress echocardiography: a report of the British Society

of Echocardiography Policy Committee. Heart 2004; 90(Suppl 6):vi23–30.

Chapter 1

Ultrasound

Introduction 2

Sound waves and ultrasound 2

Transthoracic transducers 4

Transoesophageal transducers 6

Other transducers 6

Echocardiography modes 8

Behaviour of ultrasound in tissue 12

Reflection, attenuation, and depth compensation 14

Reverberation artefacts 16

Transmit power 18

Gain 18

Grey scale and compress 18

Image resolution 20

Second harmonic imaging 22

Doppler echocardiography 24

Continuous wave Doppler 26

Pulsed wave Doppler 28

Colour flow mapping 30

Tissue Doppler imaging 32

3D echocardiography 34

3D artefacts 38

Image display 40

3D image rendering 42

Speckle tracking echocardiography 44

Second harmonic mode Doppler for contrast imaging 48

Power mode (amplitude) imaging 48

Basic fluid dynamics

Is ultrasound safe?

CHAPTER 1 Ultrasound

Introduction

Echocardiography is a non-invasive method for imaging the living heart.

• It is based on detection of echoes produced by a beam of ultrasound

pulses transmitted into the heart. A working knowledge of the

principles and basic concepts of ultrasound imaging is fundamental to

understanding clinical applications and is necessary for accreditation

examinations.

• Understanding the limitations both of fundamental physics and current

technology can ensure image acquisition is performed in a way that

drastically reduces image distortion and artefacts. This will reduce the

chance of misdiagnoses.

• An understanding of the concepts behind how images are generated

helps the operator to optimize, interpret, and analyse images.

• This chapter is aimed at a basic review of the fundamental principles of

echocardiography that will help the clinician get the most out of, and

understand the limitations of the technique.

Sound waves and ultrasound

Sound waves are often simplified to a description in terms of sinusoi-

dal waves which are characterized by the properties (Fig. 1.1):

• The frequency (f, number of cycles per second).

• The wavelength (λ, the distance between two identical points on

adjacent cycles).

• The velocity (v, the direction and speed of travel).

The relationship between these properties is described by the formula:

V = f λ

• In soft body tissues pressure waves travel at about 1500m/s (compared

with 300m/s in air).

• Thus, in soft body tissues, at a frequency of 1000Hz (= Hertz, or cycles

per second), the wavelength is 1.5m. Common-sense dictates that this

wavelength is too great to image the heart, which is only about 15cm

across and which contains structures less than 1mm thick. To achieve a

wavelength of 1mm, the frequency has to be 1,500,000 Hz, or 1.5 MHz.

• The human ear responds only to frequencies from about 30 Hz to

15,000 Hz, and since the word sound implies a sensation generated

in the brain, the term, ultrasound is used to describe the much higher

frequencies used in echocardiography.

CHAPTER 1 Ultrasound

Transthoracic transducers

• The transducer (or ‘probe’) held on the patient’s chest transmits

high-frequency ultrasound waves into the thorax and detects echoes

returning from the heart and great vessels (Figs. 1.2 and 1.3).

• The transducer contains a layer of piezoelectric crystals which have

several properties:

• They are able to generate and receive ultrasound waves.

• When a current is applied the crystal expands and compresses

which generates the ultrasound wave.

• When an ultrasound wave strikes the piezoelectric crystal an

electric current is generated.

• The transducer emits and then switches into receiving mode.

The repetition of this cycle allows the scanner to build an ultrasound

image.

• The velocity of these high-frequency sound waves generated by the

transducer depends on the physical properties of the tissues through

which it is travelling.

• Transducers for echocardiography typically generate frequencies in the

range 1.5-7MHz.

• Denser tissues allow faster propagation. Thus, in softer body tissues

like the heart, the waves travel slower (1540m/s) than in harder tissues

like bone (2000-4000m/s).

Stand-alone probe

The stand-alone continuous wave (CW) Doppler probe comprises a

single transmit element and a single receive element. The probe is con-

sidered to provide more accurate estimation of transaortic velocities

(Fig. 1.4).

3D matrix array transducers

• Matrix array transducers (Figs. 1.2 and 1.3) are used to generate 3D

pyramidal volumes in live real time (approximately 30° × 60° in size)

or full volume datasets which are not in real time (approximately

100° × 104° in size).

• The transducer uses 3000-4000 elements arrayed in a 2D phase.

Differences between cardiac and vascular transducers?

• Vascular ultrasound uses linear array transducers as it is designed

to image linear structures—blood vessels. The elements are aligned

along an axis enabling the beam to be moved, focused, and deflected

along a plane.

• As the objects of interest are closer to the probe, higher frequencies

can be used for vascular imaging.

• 3D imaging using a matrix array probe is possible. Vascular 3D

imaging tends to be based on scanning the artery and creating a 3D

reconstruction from a series of 2D images.

• Cardiac transducers tend to have a curved array of elements to

image a volume.

CHAPTER 1 Ultrasound

Transoesophageal transducers

• The probe (Fig. 1.5) is similar in construction to a gastroscope, but

in place of the fibre-optic bundle used for light imaging, a miniature

ultrasound transducer is mounted at its tip.

• The plane of the transducer array can be rotated by the operator to

provide image planes that correspond to the orthogonal axes of the

heart despite the fact that these are not naturally aligned with the axis

of the oesophagus.

• Precautions have to be taken to prevent accidental harm to the

patient through heating and the potential for it to apply 150V electrical

impulses to the back of the heart requires it to be checked regularly to

ensure integrity of the electrical insulation.

2D imaging from a transducer positioned in the oesophagus has advantages:

• There is no attenuation from the chest wall.

• It can operate at higher frequencies (up to 7.5MHz), improving image

quality.

3D transoesophageal imaging is increasingly being used, e.g. analysis of

valvular structure and to guide interventional procedures:

• The most recent 3D transoesophageal echocardiography (TOE)

probes utilize fully sampled matrix array transducers to allow real-time

3D imaging.

• A 2-7MHz transducer incorporates 2500 elements that allow

acquisition of a pyramidal 3D data set.

Other transducers

Intracardiac probes

• Intracardiac echocardiography (ICE) allows visualization of cardiac

structures within the heart (see Chapter 8).

• ICE probes (Fig. 1.6) have been used for almost 30 years. They provide

improved resolution imaging but due to the high frequency of the

transducers (20-40MHz), penetration of the earlier probes was poor.

• The latest ICE probes have improved characteristics:

• Linear phased array and lower multifrequency range (5-10MHz).

• Capability of both pulsed and colour Doppler imaging.

• Improved manipulation with the use of multidirectional steerable

devices.

• A steering lock to maintain catheter angulation.

Intravascular ultrasound probes

• High frequency intravascular transducers (30-40MHz) allow imaging

from within the coronary arteries.

• The probe positioned in the lumen of the artery emits ultrasound

waves which penetrate into the vascular wall. Reflections are created

at interfaces between tissue components of different acoustic

properties (e.g. plaque, calcification and thrombus).

• High-resolution cross-sectional images are produced allowing

measurement of luminal diameter and characterization of the vessel wall.

CHAPTER 1 Ultrasound

Echocardiography modes (Figs. 1.7, 1.8)

• Modern echocardiography machines use arrays of crystals which send

out several ultrasound waves across the sector of view.

• Each line of reflected ultrasound waves is then collated to produce an

image of the heart.

• Returning echoes strike the piezoelectric crystals, first from structures

closest to the transducer, followed in succession by those from more

distant interfaces.

• The minute electrical signals generated are amplified and processed

to form a visual display showing the relative distances of reflecting

structures from the transducer, with the signal intensities providing

some information about the nature of the interfaces.

• Repeating this sweep of ultrasound waves across the sector multiple

times per second allows a moving image to be produced. Hence the

spatial resolution of the image is determined by the distance between

scan lines and number of scan lines per sector; the temporal resolution

is determined by the number of sweeps across the sector per second

(frame rate).

CHAPTER 1 Ultrasound

A (amplitude)-mode echocardiography

• The oldest type of ultrasound generation was created using A-mode

echocardiography. Here, the amplitude of the reflected ultrasound

wave is plotted against the distance from which the reflection

originates (not in clinical use).

B (brightness)-mode echocardiography

• In B-mode imaging the amplitude of the reflected ultrasound wave is

recorded by the brightness (intensity) of a dot (not in clinical use).

M (motion)-mode echocardiography

• The reflection of the ultrasound signals are recorded and displayed as

monochromic dots over time (Fig. 1.8).

• The direction of the ultrasound beam is fixed, and interrogates

structures along a single axis over time, allowing a very high temporal

resolution when compared to 2D techniques (1000 lines/second

compared to 25 lines/second for a 2D image).

2D echocardiography

• Transducer technology allows the ultrasound beam to be scanned

rapidly across the heart to produce 2D tomographic images.

3D echocardiography

• The latest transducers are able to instantly acquire the image

contained in a pyramidal volume enabling the generation of a

3D data set.

CHAPTER 1 Ultrasound

Behaviour of ultrasound in tissue

• When ultrasound waves pass through tissue they undergo reflection,

refraction or scattering (Fig. 1.9).

Reflection

• As ultrasound waves pass through the chest towards the heart they

encounter several interfaces between different body tissues, e.g.

pericardium and myocardium.

• Some of the incident energy is reflected at these interfaces as they act

like a mirror, in the same way as light bounces back off a shiny surface.

• Reflected sound waves are termed ‘echoes’, and having undergone

‘specular’ (mirror-like) reflection they are termed ‘specular echoes’.

• The reflected ‘echoes’ are transmitted back to the transducer and

vibrate the piezoelectric crystals to form a signal from an electrical

signal, from which a picture of the heart can be built.

• The minute electrical signals generated are amplified and processed

to form a visual display showing the relative distances of reflecting

structures from the transducer, with the signal intensities providing

some information about the nature of the interfaces.

Refraction

• Refraction is the change in direction of a wave due to a change in

its speed. This is most commonly observed when a wave passes from

one medium to another at any angle other than 90° or 0°.

• Refraction of light is the most commonly observed phenomenon,

(e.g. the apparent bending of the angle of a pencil sitting in a glass of

water) but any form of wave, including ultrasound waves are subject to

refraction.

Scattering

• Specular echoes used to form images of the heart arise from tissue

interfaces.

• When ultrasound encounters much smaller structures, it interacts with

them differently: instead of being reflected along a defined path they

are scattered equally in all directions.

Reflection, scattering, and image quality

• Some tissues within the heart allow a lot of specular reflection

(pericardium, epicardium, endocardium, and valves) and have

high signal intensity on echocardiography, others produce a lot of

scattering (i.e. myocardium).

• Blood produces very little reflection and as such has very low signal

intensity on echocardiography. This allows the myocardium to be

easily differentiated from the blood.

CHAPTER 1 Ultrasound

Reflection, attenuation, and depth

compensation

Ultrasound waves are quite severely attenuated (Fig. 1.10) as they pass

through ‘spongy’ tissues such as fat and muscle. The degree of attenuation

depends greatly on the ultrasound frequency.

• The proportion reflected at a tissue interface depends mainly on the

difference in density of the tissues. Where there is a large difference—

such as an interface with air or bone—most of the incident wave

is reflected, creating an intense echo but leaving little to penetrate

further to deeper structures. It is for this reason that the operator

has to manipulate the transducer to avoid ribs and lungs, and that a

contact gel is used to eliminate any air between the transducer and the

chest wall.

• In contrast, there is relatively little difference in the densities of blood,

muscle, and fat, so echoes from interfaces between them are very

small—about 0.1% of the incident amplitude.

• Not only is this a very small signal to detect, but the amplification

level required would be vastly greater than that needed for the same

interface closer to the transducer. To overcome this problem, the

machine provides depth compensation or time-gain compensation

(TGC). This automatically increases the amplification during the time

echoes from a particular pulse return, so that the last to arrive are

amplified much more than the first.

• Most of this compensation is built into the machine, but the user

can fine-tune it by means of a bank of slider controls that adjust the

amplification at selected depths.

• The reflection and attenuation characteristics of various media can be

used to help in their identification. In particular, an interface with air

generates a very strong reflection at the proximal boundary, beyond

which the air strongly attenuates the beam casting a dark shadow.

CHAPTER 1 Ultrasound

Reverberation artefacts

• Reverberation artefacts are produced by the presence of structures

with transmission and attenuation characteristics very different from

that of soft tissue (i.e. the heart).

• The reflected echoes bounce back and forth between the highly

reflective object and the transducer (Fig. 1.11).

• In a reverberation artefact, the ultrasound wave is reflected back into

the chest from the transducer-skin interface and are common sources

of misinterpretation of images creating secondary ‘ghost’ images.

Under normal circumstances this effect is not seen because soft-tissue

reflections are so weak and secondary reflections are too small to

• However, if the object is a very strong reflector such as a calcified or

prosthetic valve, then the secondary or higher-order reverberation

echoes are strong enough to be detected.

• The clue to their recognition is that they are always exactly twice

as far away from the transducer as a high-intensity echo, and if the

primary structure moves a certain distance, the multiple reflection

echo moves twice as far.

Clues to avoid and recognize reverberation artefacts

• Beware of objects that are only seen in one imaging plane.

• Beware of objects that do not respect anatomical boundaries,

e.g. a valve lying over a chamber wall or a line lying outside the

heart.

• Beware of objects that are twice as far from the transducer as

intense reflectors.

• Use the minimum power necessary to obtain an image.

• Use adequate ultrasound gel.

• Rotating the patient or changing the angle probe to move the

artefact if it is in the required field of view.

CHAPTER 1 Ultrasound

Transmit power

• The amplitude (ultrasound strength) of the transmitted ultrasound

wave is controlled by the transmit power (or mechanical index).

• Commercially available echocardiography systems are usually set to a

default transmit power to ensure there are no adverse effects on the

tissue being imaged, e.g. for native imaging MI >1.0.

• The adjustment of the transmit power is particularly important during

contrast opacification studies to reduce contrast bubble destruction.

Gain

• The brightness of an image depends on the amount of ultrasound

signal received by the probe from the reflected echoes.

• The intensity of the reflected signal is dependent on the depth of the

structure being imaged (increased distance reduces signal) and the

inherent reflective properties of the object being imaged.

• Objects in the near field appear brighter than those in the far field.

In order to compensate for this depth compensation or time gain

compensation (TGC) is used, which enhances the intensity of signals

returning later (and as such further away from transducer).

• TGC automatically increases the amplification during the time echoes

from a particular pulse return, so that the last to arrive are amplified

much more than the first.

• Most of this compensation is built into the machine, but the user

can fine-tune it by means of a bank of slider controls that adjust the

amplification at selected depths.

• Too high levels of gain result in noise making images appear like

‘a snowstorm’ and difficult to interpret (Fig. 1.12).

Grey scale and compress

• The intensity of an echo depends on the nature of the tissue interface.

There are a wide range of echo intensities, with a calcified structure

generating an echo many thousands of times more intense than a

boundary between, say, blood and newly formed thrombus.

• The limited dynamic range of the display system can only represent

a fraction of this range (the difference in light intensity between

‘black’ ink printed on ‘white’ paper is only a factor of 30 or so). As a

consequence, ultrasound images show all intense echoes as ‘white’, all

weak echoes as ‘black’, and almost no grey tones.

• The number of levels of grey (or the dynamic range) can be altered so

that a range of grey levels in between black and white appear, but at

the expense of boundary definition (Fig. 1.12).

CHAPTER 1 Ultrasound

Image resolution

• Temporal resolution is the overall visualized image quality with respect

to time, a compromise between the frame rate, angle width and

depth. Shallower imaging depths and narrower sector widths will both

increase temporal resolution.

• Axial resolution is the minimum separation needed so that two

interfaces located in a direction parallel to the beam (i.e. above

and below each other) can continue to be imaged as two separate

sampling points rather than one. It can be optimized by employing a

higher ultrasound frequency.

• Lateral resolution is the resolution side to side, across the 2D image:

the minimum separation of two sampling points aligned perpendicular

to the ultrasound beam so that they continue to be imaged as two

separate interfaces rather than one. It is primarily determined by the

distance from the transducer and, as the echo beam widens with

increased depth the lateral resolution decreases.

• Spatial resolution is a measure of how close two reflectors can be to

one another so that they can still be identified as different reflectors.

Focusing

• Lateral resolution is the chief factor limiting the quality of all

ultrasound images and is worse than axial resolution by something

like a factor of 10. To improve it, the ultrasound beam must be made

narrower by focusing it.

• A plastic lens is fitted on the face of the transducer, in the same way

that a glass lens focuses light, though less effectively. Transducers can

be constructed with short-, medium-, or long-focus lenses.

• The pulsing sequence that steers the beam can be electronically

modified to provide additional focusing. This adjustment can be made

by the operator.

Transducer frequency and spatial resolution

• The frequencies of various probes differ depending on the application

(see Table 1.1).

• The choice of transducer frequency is determined by the depth of

imaging and the resolution required.

• Low frequency transducers have good penetration but because of the

longer wavelength, poorer resolution.

• High frequency transducers have good resolution but poor

penetration.

• Higher frequency transducers with better resolution can be used

where less depth is required, e.g. when imaging children or TOE.

• Intravascular ultrasound requires very little penetration but very high

resolution and therefore uses very high frequencies.

CHAPTER 1 Ultrasound

Second harmonic imaging

• The frequency of the ultrasound wave sent out is the fundamental

frequency.

• The target tissue expands and compresses in response to the wave

which in turn causes distortion of the sound wave. This distortion

generates additional frequencies called harmonics.

• This change in wave shape can be shown mathematically to be due

to the addition of a frequency twice that of the original transmitted

frequency (called its ‘second harmonic’) (Fig. 1.13).

• Harmonic frequencies are larger than the fundamental frequency.

• Both harmonic and fundamental frequencies will return to the

transducer but by filtering out the original fundamental frequency it is

possible to receive the higher harmonic frequencies preferentially.

Advantages

• Harmonic imaging combines the penetration power of a transmitted

low fundamental frequency with the improved axial image resolution

of the harmonic frequency which is twice that of the fundamental

frequency.

• The harmonic image is derived from deeper structures and thus

reduces artefacts from proximal objects such as ribs.

• The harmonic image away from the central beam axis is relatively

weak and thus not so susceptible to off-axis artefacts.

Disadvantages

• As the image is now formed from echoes of a single frequency, some

‘texture’ is lost and structures such as valve leaflets may appear

artificially thick.

• If the quality of the fundamental frequency image is very good, such

that second harmonic mode offers little benefit, it may be better not

to use it, but in most patients the improvement in image quality greatly

outweighs this minor disadvantage.

CHAPTER 1 Ultrasound

Doppler echocardiography

Doppler imaging allows the determination of the direction and speed of

blood flow and is used for the detection and assessment of cardiac valvu-

lar insufficiency and stenosis as well as a large number of other abnormal

flow patterns.

The Doppler effect (Fig. 1.14)

• First described in 1842, Doppler hypothesized that certain properties

of light emitted from stars depend upon the relative motion of the

observer and the wave source.

• Consider a ship setting sail from the shore with an incoming tide with

a wave frequency of one wave per minute. As the ship is moving out

to sea would it meet the waves with more frequency than one per

minute? The converse is also true that if the same ship turned around

to set sail to shore, it would meet less than one wave per minute.

• Although initially described for light, the Doppler effect applies to all

waveforms including ultrasound. As blood is moving, the frequency of

the backscattered echoes is modified by the Doppler effect, termed

‘the Doppler shift’.

• The change in frequency of reflected echo waves will be either

increased if blood is travelling towards the probe or decreased if

travelling away from the probe, with the size of the Doppler shift

determines the speed of the blood.

The Doppler equation describes the change in frequency that occurs:

2f V cosθ

Δ =

• ZF is the Doppler shift in frequency.

• fo is the ultrasound frequency of the transducer.

• V is the velocity of the blood.

• θ is the angle between the flow and the ultrasound beam.

• C is the velocity of ultrasound in tissue (1540 m/s).

The returning ultrasound signal is demodulated to extract the Doppler

shift and the velocity is then determined.

Doppler shifts are usually in the audible range (20Hz-20KHz) and heard

during the Doppler examination, the higher the pitch of the sound the

higher the Doppler shift and blood velocity.

CHAPTER 1 Ultrasound

Continuous wave Doppler

• Continuous wave (CW) Doppler requires transmission of a

continuous train of ultrasound waves, with simultaneous reception of

the returning backscattered echoes (Fig. 1.15).

• The frequency of backscattered echoes from moving blood is different

to that from the transmitted frequency. This difference is known as the

Doppler shift or Doppler frequency.

• As blood in an artery does not flow at a constant rate, the ultrasound

beam generates a large number of different Doppler frequencies, all

of which are used by the machine to generate the spectral Doppler

display.

• This all requires two piezoelectric crystals (one for transmission one for

reception) rather than the one used in pulsed wave Doppler (Fig. 1.16).

• Different probes have different arrangements of crystals with stand

alone ‘pencil’ probes having separate transmit and receive crystals and

normal probes assigning crystal groups to either a transmit or receive.

• As transmission and reception of ultrasound is continuous it can’t

provide depth discrimination, and a particular Doppler shift may have

arisen from anywhere along the beam axis.

• Although this would appear to be a problem, it usually is not the case

in clinical practice, since identification of the source of a high-velocity

jet is usually apparent from the 2D image and from the flow velocity

profile.

• The density of the spectral trace is proportional to the amplitude of

the signal at each Doppler frequency and thus a representation of the

blood flow at that velocity.

Limitations of CW Doppler for measuring pressure

gradients

• For successful application of CW Doppler the ultrasound beam

needs to be aligned accurately with the direction of blood flow

(within 15° of the flow, for which the cosine is 0.97 and error in the

value of [velocity]2 is <7%).

• A colour-flow image can be used to guide beam alignment and in the

case of aortic stenosis the measurements should be checked by using

two different views (e.g. apical and upper right parasternal).

• It is also necessary to align the beam with the centre of the jet

passing through the restriction.

• The ‘pencil probe’, which is optimized for CW Doppler, is strongly

recommended for recording high-velocity valve jets.

CHAPTER 1 Ultrasound

Pulsed wave Doppler

• This is a single piezoelectric crystal technique which uses alternating

transmission and reception of ultrasound waves (Fig. 1.17).

• The depth of the region of interest (‘sample volume’) determines this

interval between transmission and reception of the ultrasound waves.

• The cycle of alternating transmission and reception of pulses is termed

the pulse repetition frequency (PRF).

• Information is gathered over a small sample, which can be moved to

any region of interest.

• The main advantage of pulsed Doppler is the high spatial resolution

that can be obtained (typically a 1-5mm sample size can be

interrogated), and is useful for investigating velocities in specific areas,

i.e. the left ventricular outflow tract.

Pulse repetition frequency

• With pulsed wave (PW) Doppler the time interval between sequential

pulses must be sufficient so that the initial pulse has enough time to

reach the target and return to the probe.

• If this interval between pulses is too short so that the second pulse is

sent before the first is received back, then it is difficult to differentiate

between reflected signals from the sample volume.

• The closer the region of interest to the probe, the higher the PRF.

• Lower PRFs are usually used to evaluate low velocities as the

increased time between pulsed transmission-reception cycles allows

better chance for the scanner to identify slower flow (e.g. venous).

Aliasing

• With pulsed Doppler, transmitted waves must be sampled at least

twice in each cycle to allow determination of wavelength (this is an

example of Nyquist’s theorem).

• The maximum velocity (Doppler shift) that can be measured

accurately is equal to half of the PRF (this value is the Nyquist limit).

• If pulsed Doppler waves travel to greater depths then the time interval

to receive the reflected signal is increased and thus the PRF is lower.

The Nyquist limit (aliasing level) is therefore lower at greater sampling

depths.

Practical considerations of PW Doppler

• The practical effect of aliasing is that the ‘tops’ of the positive

velocities that exceed the Nyquist limit are cut off and displayed as

negative velocities (Fig. 1.18).

• Provided that the flow is predominantly towards or away from the

transducer, and not bi-directional, the zero velocity baseline can be

shifted to favour one direction at the expense of the other, and it is

thus possible to increase the aliasing velocity by a factor of up to 2,

but beyond this nothing can be done.

• When looking at the display of a pulsed wave trace if the flow being

measured is laminar then the trace has a defined outline, if the flow

is turbulent then flow fills in to form a more solid flow trace.

PULSED WAVE DOPPLER

Fig. 1.17 Example of normal pulsed wave Doppler placed in aortic arch.

Fig. 1.18 Example of pulsed wave Doppler with aliasing.

High pulse repetition frequency PW Doppler

• This is the deliberate use of high PRFs to increase the aliasing

velocity and thus increase the maximum velocity that can be

measured with PW Doppler.

• Sequential pulses are transmitted without waiting for the original one

to be received. This increases the PRF and allows a spectral trace

which is not aliased.

• The trade off with using high PRFs to sample increased velocities is

that some of the ultrasound waves will penetrate beyond the depth

of interest and so signals from different sampling depths may be

recorded.

• In practice this is overcome by judicious placement of the beam to

ensure that the additional sample volumes do not arise from high-

velocity areas that are not of interest.

CHAPTER 1 Ultrasound

Colour flow mapping

• The PW Doppler principle can be extended to display a pictorial

representation of PW Doppler readings over a designated region of

interest (determined on the 2D image).

• Pulses are rapidly emitted from the probe so that sequential pulses

hit the same moving scatterer. Thus, a representation of how far the

scatterer has moved either towards or away from the probe can be

determined.

• Standard designation of colours occurs according to direction as Blue

Away and Red Towards (BART) the probe (Fig. 1.19). On CW or PW

Doppler, blood flowing towards the transducer would appear as a

spectral trace above the time line, whereas blood flowing away from

the transducer would appear as a spectral trace below the time line.

Limitations of colour flow mapping

Aliasing

• Simultaneous imaging and Doppler lower the effective PRF and aliasing

in a colour flow image typically occurs at velocities above 0.5m/s.

• Aliasing manifests on a colour display as colour inversion: red turning

to blue, and vice versa. For steady flow towards the transducer, a

velocity of 0.4m/s is represented by pale red but as it increases to

0.6m/s it becomes pale blue (Fig. 1.20). At 1.0m/s (twice the aliasing

velocity) the colour display again shows black, and with further

increase in velocity red, then blue, and so on.

Turbulent flow (variance mapping)

• When flow is turbulent, there is a wide spectrum of local velocities:

high and low, forward and reverse. This is indicated on a CW display

as broadening of the spectral band, but cannot be indicated by colour

Doppler, since it can only display flow velocity at one point and at one

time by a single colour.

• A solution is provided by analysing the time-variance of local velocity,

so that when the same pixel detects greatly different velocities in

successive images, the display is modified, for example by showing

those pixels in green.

• This is called variance mapping, but it places further strain on frame

rates and aliasing velocity.

COLOUR FLOW MAPPING

Fig. 1.19 Example of BART principle. On colour Doppler mapping flow away from

the transducer is blue and a continuous or pulsed Doppler trace (blue spectra in

figure) would appear as a spectral trace below the time line. Flow towards the

transducer is red and a continuous or pulsed Doppler trace (red spectra in figure)

would appear as a spectral trace above the time line.

Differences in colour

Region of interest

and intensity describe

velocity and direction

Fig. 1.20 Example of colour flow mapping. The homogenous blue colour in the

left ventricle indicates blood flow away from the transducer. The flow becomes

turbulent when the blood is pushed through the leaky mitral valve, which can be

seen as a mosaic pattern of different velocities.

CHAPTER 1 Ultrasound

Tissue Doppler imaging

• Tissue Doppler imaging (TDI) allows the velocities of myocardial

segments and other cardiac structures to be measured (Fig. 1.21).

• Whereas conventional Doppler techniques assess the velocity of

blood flow by measuring high-frequency, low-amplitude signals from

small, fast-moving blood cells, TDI uses the same Doppler principles

to quantify the higher amplitude, lower-velocity signals of myocardial

tissue motion (Figs. 1.21 and 1.22).

• TDI allows the measurement of myocardial motion relative to the

adjacent myocardium rather than the transducer which is susceptible

to tethering of adjacent tissue.

• High-velocity signals from blood are filtered out and amplification

scales suitably adjusted so that Doppler signals from tissue motion can

be recorded.

Practical considerations for tissue Doppler imaging

• The accuracy of TDI is angle dependent and only measures the vector

of motion that is parallel to the direction of the ultrasound beam.

• High frame rates (100-150 frames per second) should be used in order

to maximize the information gathered in the spectral trace.

• The sample volume should remain within the tissue of interest during

the cardiac cycle.

• Respiratory motion can cause drifting of the strain curve as the sample

volume moves out of the desired region of interest and therefore

images should be acquired at end expiration.

• Tissues close to the body surface can cause false echoes from their

reflections (‘reverberation artefacts’). In PW TDI these can be seen as

an increased intensity at zero velocity.

• The lowest readable gain setting should be used to acquire and analyse

the spectral trace. Too much gain increases the width of the spectrum

and increasing the gain intensity increases the peak TDI value.

Strain rate imaging by tissue Doppler

• Strain is a measure of the change in shape (‘deformation’) of a region

of interest. The relative amount of this deformation over time is

termed the strain rate.

• The peak systolic strain is the maximum deformation seen during

systole.

• Peak systolic strain rate is the maximum rate of deformation during

systole.

• Strain rate by tissue Doppler measures the velocity gradient between

two points within a segment at a fixed distance apart.

CHAPTER 1 Ultrasound

3D echocardiography

Introduction

• 3D image acquisition has the advantage of taking into account variation

in ventricular shape in all directions rather than just the two of biplane

measurements. It is dependent on capturing the whole left ventricle

within the 3D-probe sector and requires images to have good

endocardial border definition.

• 3D echocardiography is well suited for the evaluation of valvular

disease and has the advantage of offering depth as an additional

dimension over 2D echocardiography and the ability to view the valve

from multiple different angles.

• 3D image acquisitions are either true ‘live’ images or near real-time

(full volume) images. Live images offer instant feedback although are

limited by a narrow display sector. Near real-time images occur when

the electrocardiogram (ECG) recording is used to acquire individual

subvolumes over sequential cardiac cycles (Fig. 1.23).

3D acquisition modes

Full volume 3D data sets

• This mode allows the generation of a 3D data set with the final

image of the heart created by acquiring several subvolumes (usually

1-7 depending on the vendor) over the corresponding number of

sequential cardiac cycles.

• A regular cardiac rhythm and adequate breath-holding capabilities of

the patient are needed to reduce the incidence of artefact when the

subvolumes are merged together.

• The greater the number of subvolumes used, the higher the frame rate

and temporal resolution (Fig. 1.24).

• Once all of the subvolumes have been acquired a final image is formed.

This image is therefore not ‘live’.

CHAPTER 1 Ultrasound

Live 3D

• Live volume images generate real-time 3D acquisitions of the heart.

• This mode allows the generation of a 3D data set which is usually

smaller than the full volume acquisition to achieve adequate frame

rates.

• It is well suited to imaging during percutaneous interventions or closer

inspection of valvular pathology, where a smaller volume of interest is

being examined or during irregular cardiac rhythms (Fig. 1.25).

3D colour Doppler

• This combines grey scale volumetric data with colour Doppler and is

useful for examination of regurgitant lesions or shunts (Fig. 1.26).

Applications and limitations of 3D echocardiography

Applications

• 3D echocardiography has been shown to be accurate for the

assessment of left and right ventricular function and volumes.

• There has been research into whether 3D datasets provide novel

indices for left ventricular dyssynchrony assessment.

• 3D echocardiography also allows for quantification of valvular

abnormalities and also to guide cardiac interventions (e.g. PFO/ASD

closure, TAVI and mitral clip implant).

Limitations

• Misalignment can occur when the subvolumes are merged

together—called stitching artefacts, see Fig. 1.27.

• 3D image quality greatly depends on the quality of the 2D image.

CHAPTER 1 Ultrasound

3D artefacts

Stitch artefacts

• These occur during the acquisition of 3D full volume images where

subvolumes are recorded and triggered by the cardiac cycle.

• Stitch artefacts are seen when subvolumes do not neatly merge

together and instead the boundary between individual subvolumes can

be identified (Fig. 1.27).

• Causes of stitch artefacts include an irregular cardiac rhythm, probe

motion during acquisition or patient movement during acquisition

(e.g. respiration).

Drop out artefacts

• These can occur when the volume of interest is acquired and a

suboptimal gain setting used.

• For instance, when imaging the mitral valve, as the leaflets may be

quite thin then if the gain setting is too low, a drop out may occur.

• Conversely if too high a gain setting is used this may lead to other

imaging artefacts.

Attenuation artefacts

• As with 2D echocardiography, attenuation artefacts can occur. This is

the process of a gradual deterioration of the signal intensity distal to

the volume target due to reduced backscatter and absorption.

CHAPTER 1 Ultrasound

Image display

• Following the acquisition of the 3D data sets, the advantages of 3D

echocardiography become appreciated as all commercially available 3D

echocardiography machines allow post processing.

• Post processing can be performed either directly on the same unit

as that used for acquisition or indirectly via a stand alone software

package.

• The use of post processing allows visualization of cardiac landmarks

that would not have been possible with 2D echocardiography alone

(e.g. surgical ‘en face’ view of the mitral valve).

Commercially available 3D software packages are able to perform post

processing techniques (although the individual names of the techniques

vary from vender to vender):

Cropping

• This allows the operator to remove unwanted information from the

initial data set to focus solely on the target anatomy, e.g. cropping the

ventricle to view the mitral valve looking from the apical position.

• Most commercially available 3D operating systems allow cropping

(Fig. 1.28) to be performed either by rotating and removing unwanted

data in a single plane through the image or using a 3-plane technique.

Following image cropping and rendering, the

3D acquisition can be

displayed.

• There are several modes such as a volume rendered image, wire frame

display, or multiplanar reformatting (MPR) slice display where three

simultaneous orthogonal 2D-like slices can be presented.

Slice modes

• Most commercial 3D echocardiography systems offer a ‘slice’ format

through which the data can be presented (e.g. Phillips iSlice; Fig. 1.29).

• Here, the 3D image volume can initially be optimized to avoid any

foreshortening and then volume can be viewed as a number of

uniformly spaced slices in the horizontal plane.

CHAPTER 1 Ultrasound

3D image rendering

• Image rendering is vital to fully appreciate the target volume in detail.

As with 2D echocardiography, it is a process which should begin prior

to volume acquisition to ensure that the optimal image is acquired

and can be completed post image acquisition to optimize the acquired

image for visual presentation.

• Most commercial 3D echocardiography packages offer different image

rendering capabilities, the main ones being:

• Smoothness: this allows adjustment of image so that the finer detail

at closer inspection is free from minor ‘roughness’,

• Gain adjustment: it is particularly important during 3D image

optimization to carefully adjust the overall gain of the image. High

gain levels make the image appear more 2D like whereas lower

gain reveals deeper tissue structure so that deeper tissues are more

appreciated in the overall volume; see Fig. 1.30.

• Opacification/compression: this determines how solid or transparent

the final image is. Lowering the compression increases the image

transparency and vice versa.

• Brightness.

• 3D vision/colour maps: all 3D post processing systems offer a

variety of colour maps or different ‘3D vision’ which the operator

can select from, each separate selection offering a combination of

different colours to alter depth perception.

• Magnification: allows the acquired image to be enlarged to

appreciate finer structures in more detail.

CHAPTER 1 Ultrasound

Speckle tracking echocardiography

When imaging myocardial tissue, the ultrasound image of backscatter gen-

erated by the reflected ultrasound beam appears as a pattern of grey

values. This is termed the ‘speckle pattern’. The myocardial fibre orienta-

tion of the LV is complex. In healthy individuals myocardial fibres move in

several different planes which can be detected by speckle tracking.

The speckle pattern is unique for each myocardial region. Speckle track-

ing software allows individual speckles within a region of interest to be

tracked throughout the cardiac cycle, frame by frame. The scanner speckle

tracking algorithm allows the displacement, velocity, strain, and strain rate

for a myocardial region to be calculated.

Speckle tracking strain measurements

Peak strain values during systole are represented as a percentage of the final

position of the speckles in relation to their original position. Longitudinal

strain is measured from the LV apical views whereas radial and circumfer-

ential strains can also be obtained from LV short axis views (Fig. 1.31).

• Longitudinal strain: the motion from base to apex. During systole the

contraction in this plane leads to fibre shortening, represented as

a negative percentage value (i.e. the more negative the value—the

greater the deformation which has occurred).

• Radial strain: the amount of thickening of the myocardium which

occurs. During systole myocardial contraction leads to fibre thickening

in the radial plane. This is represented as a positive percentage value

(i.e. the more positive the value—the greater the deformation which

has occurred).

• Circumferential strain: the change in radius in the short axis. During

systole, myocardial contraction leads to fibre shortening. This is

represented as a negative percentage value (i.e. the more negative the

value, the greater the deformation which has occurred).

Cardiac twisting

During the cardiac cycle the left ventricle also undergoes a twisting mo-

tion. During systole the apex rotates counterclockwise whilst the base

rotates in a clockwise fashion. These movements can also be estimated

by speckle tracking:

• Rotation (degrees): the angular displacement of a myocardial

segment in the short axis view.

• Twist or torsion (degrees): the net difference between apical short

axis and basal short axis rotation.

CHAPTER 1 Ultrasound

2D vs. 3D speckle tracking (Fig. 1.32)

• All of the described strain parameters can be measured in 2D. In

reality, speckles move through 3D space rather than remaining

within the 2D sector (Fig. 1.32).

• Newer technology is now available allowing the measurement of 3D

speckle tracking strain (Fig. 1.33). This has the advantage of tracking the

motion of speckles within the scan volume, irrelevant of its direction.

Practical considerations for speckle tracking

• Unlike TDI, speckle tracking is an angle-independent technique and so

the transducer can be placed off axis to obtain the optimal image.

• Clear delineation of the endocardial border is necessary for reliable

tracking.

• To reduce through plane motion acquisitions should be made during

breath hold.

• Drop out or reverberations if present are sometimes tracked, resulting

in incorrect calculation of strain.

• The optimal frame rate for acquisition of images is around 50-90

frames per second (FPS), much lower than frame rates needed for TDI

(>120 FPS). In patients with tachycardia or during rapid events in the

cardiac cycle, these lower frame rates mean that there may be under

sampling, with peak strain and strain rate values being lower than the

true value.

• Higher frame rates will reduce the problem of under sampling but at

the expense of spatial resolution. Lower frame rates are thus used to

ensure optimal spatial resolution but care must be taken not to lower

the frame rate too much otherwise the speckle will not be able to be

tracked from frame to frame.

• A good balance between temporal and spatial resolution can be

achieved by adjusting the sector width so that it is just wider than the

myocardial wall.

• Whilst optimizing the image quality is important, it is also necessary to

remember that speckle tracking is also dependent on the implemented

vendor algorithm. Different vendor algorithms may produce different

results.

Langranian and natural strain

There are two types of strain, Lagranian and natural strain. Lagrangian strain

is defined on the basis of deformation from an original length. Whereas,

natural strain is defined relative to deformation from a length at a previ-

ous time, which may not necessarily be the original length. Natural strain

is more relevant to cardiac imaging as you may want to know how strain

changes during the cardiac cycle rather than just relative to the start.

CHAPTER 1 Ultrasound

Second harmonic mode Doppler for

contrast imaging

• Second harmonic imaging was originally developed in order to enhance

signals from encapsulated contrast media (see Chapter 9).

• These are proprietary products and comprise very small (1-3μm)

microspheres of gas contained within a hard outer shell.

• At very low ultrasound power levels, the microspheres act as

conventional scatterers, but with slightly greater power (though still

lower than normally used for imaging) the pressure waves distort them

and they vibrate, emitting energy at the second harmonic frequency.

• A display derived from the second harmonic Doppler frequency thus

selectively comes from the microspheres and not from surrounding

tissue or blood.

• The addition of contrast greatly enhances the quality of both images

of blood-filled cavities and of Doppler signals, giving a clear velocity

profile for even very small jets.

• At higher ultrasound power levels, the microspheres shatter, releasing

the contained gas, and generating a brief, but very intense, echo.

Power mode (amplitude) imaging

• As stated previously, the Doppler shift is determined by velocity, but

the intensity of the Doppler signal relates to the number of scatterers

within the ultrasound beam.

• If there are a lot of scatterers moving in random directions, the net

velocity will be zero, but the amplitude of the Doppler signal quite

high.

• A display showing the amplitude or power of the Doppler signal shows

the density of scatterers, regardless of the velocities. This type of

display is used, often in conjunction with harmonic mode, in contrast

studies.

CHAPTER 1 Ultrasound

Basic fluid dynamics

Volumetric flow

• For steady-state flow (i.e. when velocity is constant) the volume of

liquid flowing through a pipe for a given time period (T) is the product

of the cross-sectional area of the pipe (A) and the mean velocity (V).

Volume = A x V x T

• If flow is pulsatile (e.g. blood flow in the circulation) then velocity

increases and decreases over time. The product of velocity and time is

replaced by use of the velocity time integral (VTI).

VTI = (∫V x dT)

Continuity equation (Fig. 1.34)

• If a fluid, which is not compressible, flows along a rigid-walled pipe, the

amount entering one end of the pipe must be the same as that leaving

the other end.

• If the diameter of the pipe is greater at the end than the start (i.e.

cone-shaped) this still holds true.

• In order to maintain flow across a reduced cross-sectional area an

increase in mean velocity of flow must occur.

• This is the explanation for the increased flow speed when squeezing

the end of a hose pipe. This basic principle is described by the

continuity equation:

A1 x V1 = A2 x V2

Where:

• A1 is the cross sectional of area of the entrance to the tube.

• V1 is the velocity of flow at position A1.

• A2 is cross sectional of area of the exit of the pipe.

• V2 the velocity at position A2.

• Providing that three of the terms in the equation are known, the

fourth can be derived.

• The equation is used, for example, to determine the valve area in

aortic stenosis:

• Area of the left ventricular outflow tract (ALVOT) is taken as the

entrance to the tube (assumed to be circular and calculated from

diameter as π rLVOT2)

• Entrance flow being pulsatile is replaced with velocity time integral

measured with pulsed wave Doppler in the left ventricular outflow

tract (VTILVOT).

• Exit flow is measured as the velocity time integral across the aortic

valve (VTIAV) with continuous wave Doppler, i.e.:

ALVOT x VTILVOT = AAV x VTIAV

BASIC FLUID DYNAMICS

Cross-sectional area

e.g. = 2 cm²

Velocity

e.g. = 1cm/s

Volume = cross-sectional area × velocity × time

e.g. 2 × 1 × 1 = 2cm³

2 × 1 × 2 = 4cm³

After 1 second

After 2 seconds

Velocity

Actual velocity profile

Time

Volume during time period 1 =

Mean velocity during 1 × Time period 1 × Cross-sectional area

Total volume = Volume during 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8

Velocity

Actual velocity profile

Area under the curve

= velocity time integral

Time

Total volume =

Velocity time integral × Cross sectional area

Volume of blood that passes through pipe 1 in fixed time period

must equal volume that passes through pipe 2 in same time period

Area 1 × Velocity 1 = Area 2 × Velocity 2

Area 1

Velocity 1

Area 2

Velocity 2

Pipe 1

Pipe 2

Fig. 1.34 Continuity equation.

CHAPTER 1 Ultrasound

Bernoulli equation (Fig. 1.35)

• The Bernoulli equation describes the relationship between pressure

and velocity of a flow within a tube of fixed diameter.

• Liquid only flows along a pipe if there is a pressure difference between

its ends.

• For a fixed pipe diameter, and steady-state flow, only a small pressure

difference is required to overcome frictional losses.

• If the pipe becomes narrower in order to increase flow velocity

(necessary to maintain flow) a higher pressure difference is required

across the pipe. Again this is observed when putting your thumb on

the end of a hose pipe, the pressure against your thumb increases as

the velocity of water coming out of the narrowed end increases to

maintain a steady state of flow through the pipe.

Neglecting the frictional losses, the relationship between pressure and

velocity is:

- V12)

Where:

• V1 is the velocity upstream to the narrowing.

• P1 is the pressure at that point upstream to the narrowing.

• V2 is the velocity after the narrowing.

• P2 is the pressure after the narrowing.

• ρ is the density of the liquid.

• In most clinical cases of obstructed blood flow (e.g. aortic stenosis)

the velocity before the narrowing (V1) is small compared to that after

the narrowing (V2), for example 1m/s in the left ventricular outflow

tract versus 4m/s across the aortic valve, and the difference is further

magnified when the values are squared (i.e. V1 = 1 and V2 = 16) The

equation simplifies by removing V1 with little change in the pressure

results and becomes:

• In echocardiography the pressure difference relates to blood (for

which ρ is constant), the pressure is measured in mmHg and velocity

in m/s. The equation can then be simplified further to:

• If the upstream velocity is not small compared to the downstream for

example in combined hypertrophic cardiomyopathy and aortic stenosis

where a muscular subvalvular restriction can be combined with a valve

stenosis then is not possible to omit V1 from the Bernoulli equation.

• It is always worth remembering that a velocity of 2m/s across an aortic

valve does not represent a pressure gradient of 16mmHg across the

valve if the velocity in the outflow tract is 1.5m/s. In these cases (and

for BSE exams) the full equation is:

- V12)

CHAPTER 1 Ultrasound

Is ultrasound safe?

• No case of harm to a patient from diagnostic ultrasound has ever

been documented in adult echocardiography. By any standards, the

risk:benefit ratio of echocardiography is negligibly low, but there is

no such thing as zero risk and to minimize it the user should always

employ the ‘ALARA’ principle (As Low As Reasonably Achievable) for

machine power levels and patient exposure times.

• Ultrasound at high power levels can be used to coagulate tissues,

heat deep muscles, or clean dirty surgical instruments; however,

commercially available ultrasound machines do not allow the

transmission of power which may have potentially adverse bio-

effects. Potential harmful effects are related to the beam intensity and

ultrasound frequency.

Thermal index

• The energy lost through attenuation as the beam passes through

tissues is largely converted to heat. The peak intensity as the

ultrasound pulse passes may be quite high, but there are large gaps

between pulses (pulse duration 2μs, interval between pulses 200μs) so

the average heating is quite low.

• The term used to express this is thermal index and is the ratio of the

actual beam power to that required to raise the temperature of a

specific tissue by 1ºC.

Temperature and transoesophageal echocardiography

A particular issue arises with transoesophageal scanning, where the

transducer face is in contact with the oesophagus and local heating

could, in the event of a fault within the transducer, cause tissue necrosis.

For this reason, the probe tip temperature is monitored and there is an

automatic thermal cut-out if it becomes too high.

Mechanical index

• Increasing transmitted power causes higher pressure fluctuations as

the ultrasound waves travel through tissues.

• The potential for harm is quantified by the mechanical index (MI), a

parameter derived by dividing the peak negative wave pressure by the

square root of the ultrasound frequency. Most commercial cardiac

scanners limit the maximum power to MI 1.1.

Contrast echocardiography

In contrast, echocardiography safety issues relate to the contrast itself and

how it is broken down. Tissue bio-effects are negligible at the diagnosti-

cally recommended scanner settings. However, allergic or pseudo allergic

reactions are possible but very rare (see b p.570).

Chapter 2

Transthoracic

examination

Patient information 56

Patient preparation

Preparing machine and probe 58

Probe handling and image quality 58

2D image acquisition 60

3D image acquisition 62

Multiplane image acquisition 64

Data acquisition

Parasternal long axis view

Parasternal right ventricle inflow view

Parasternal right ventricle outflow view

Parasternal short axis (aortic) view

Parasternal short axis (mitral) view

Parasternal short axis (ventricle) views

Parasternal 3D views 76

Apical four chamber view 78

Apical five chamber view 80

Apical two chamber view 82

Apical three chamber view 84

Apical 3D views 86

Subcostal views 88

Inferior vena cava view 90

Abdominal aorta view 90

Suprasternal view 92

Right parasternal view 94

Standard examination 96

CHAPTER 2 Transthoracic examination

Patient information

• Transthoracic echocardiography is a simple, non-invasive investigation.

The patient can be given simple information on what is intended and

how the pictures are created with sound waves.

• They should be aware that they will need to undress to the waist and

lie on a bed on their side for around half an hour. If there is a sex

discrepancy between echocardiographer and patient there should be

the option of a chaperone.

• The operator should be alert to the fact that the patient may find lying

in a fixed position on one side for a period of time uncomfortable

(e.g. hip or knee problems) and give opportunities for the patient to

move or consider alternative imaging positions. Furthermore the patient

may find having the probe pressed against the chest uncomfortable.

• The operator should be aware of any complicating medical problems

such as increased body mass index, chest deformities, lung disease,

breast disease, or heart failure that may make imaging difficulty.

Patient preparation

• Ask the patient to undress to the waist and explain that this is ‘so you

can image the whole of the heart’. A woman may appreciate a sheet or

gown to cover them while preparations are in progress.

• Ask them to sit on the couch. The ideal position is with the patient

sitting up at 45º supported by the raised head of the couch but rolled

over onto their left side. Patients can find the concept of lying on their

left side while sitting up confusing. They tend to slide down the bed

on rolling over and end up lying down. Demonstrate the position if

necessary and explain that they need to lie on their left side to ‘bring

the heart close to the chest wall’. If the patient is more comfortable lying

flat this is an acceptable alternative position.

• Ask them to raise their left arm and place their hand behind their head

(some couches have a handle to hold onto). Explain that this is to

‘make it easier to get to the heart’.

• Make sure the patient is comfortable as they will need to stay in

position for sometime.

• Attach ECG electrodes between patient and ultrasound machine

and check there is a clear trace on the screen both to time images

and trigger loop capture. Aim to have a large QRS complex without

artefact. Usually the red electrode is placed by the right shoulder,

yellow by left shoulder, and green on the lower chest (usually away

from the apex to avoid the imaging window). Alternative positions are

with the yellow electrode on the back and/or red in the centre of the

chest. Consider more careful skin preparation or changing electrode

stickers if the trace is not clear. Some machines allow you to rotate

through lead combinations (e.g. I, II, III) to find the best trace. ECG

gain can be changed to increase the size of the QRS complexes.

• Enter patient demographic details (and, ideally, details of body size)

onto the machine.

CHAPTER 2 Transthoracic examination

Preparing machine and probe

• Set up an ergonomic orientation of machine, patient, and operator.

This will depend on your preferred operator position. A standard way

is to have the operator sitting behind the patient on the edge of the

couch with their right arm holding the probe and wrapped over the

patient. The machine is then operated with the left hand. Another

standard method is to sit facing the patient holding the probe against

the chest wall with the left hand (arm rested on the couch) and with

machine operated by the right hand.

• Check transthoracic image settings on machine, with harmonic imaging

(if available) and your preferred image post-processing options

selected. Set overall gain, compress and transverse or lateral gain

controls to standard positions.

• Make sure there is an ECG tracing on the echo machine and patient

details are entered.

• Make sure image storage is possible (to magneto-optical disc,

download to image server or videotape).

• Take the appropriate transthoracic probe, apply gel to transducer and

start imaging.

Probe handling and image quality

• The probe should be held in one hand and pressed firmly against

the chest wall. Varying the pressure will alter image quality. Ensure

sufficient pressure to optimize the image but not too much to make it

uncomfortable for the patient. The usual problem while learning is not

to apply enough pressure to get good image quality.

• A layer of gel ensures good contact between probe and chest wall.

It excludes any air (that would degrade image quality). However, too

much gel makes it difficult to keep a stable position so, once a layer

is established, try not to apply more gel as image quality will not

improve.

• The probe has a dot on one side to orientate the probe in your hand

with the image on the screen.

• The probe can be moved in multiple directions but the four key

movements are (1) rotation around a point, (2) rocking back and

forwards, (3) rocking side to side, and (4) sliding across the chest.

Movements needed to improve image quality are usually quite small

and with experience hand movements are almost subconscious.

• Remember that image quality may be improved by different patient or

heart positions. These can be altered by physically rolling the patient,

a little, one way or the other, readjusting the patient to ensure they

are sitting up, or asking the patient to breathe in or out to move the

diaphragm (and heart) up or down.

• Imaging well is hard work and requires concentration. If it is proving

difficult to find, keep, or return to an image during a study remember

a short break can help. Remove the probe from the chest, re-apply gel

and start again.

PROBE HANDLING AND IMAGE QUALITY

2D image optimization

There are four things that can be altered to improve image quality.

Check each when you change a view to ensure you have the optimal

image. In certain situations a completely different approach is needed,

e.g. contrast imaging.

• Contact between probe and chest—this minimizes acoustic loss

between probe and heart. Ensure there is a sufficient layer of gel and

that you are applying enough pressure on the probe (more pressure

might be needed if there is significant fat or tissue under probe).

• Patient position—this can move the heart closer to the probe.

Ensure the patient has not slipped out of position. See if rolling the

patient slightly, one way or the other, improves the image.

• Cardiac and lung position—these two factors are altered by asking

the patient to breath in or out. The heart moves up and down with

the diaphragm and any lung tissue between the probe and heart

(which contains air and therefore degrades the image) may also

move out of the way. Ask the patient to breath in and out slowly.

Watch the image. The best image may be at end inspiration or end

expiration, or somewhere in between! Ask the patient to hold their

breath when the image is at its best.

• Machine settings.

• Machines usually have tissue harmonic imaging, which should routinely

be selected.

• Overall, as well as, transverse and lateral gains should be adjusted

along with contrast controls (e.g. compress) to optimize contrast

between blood and myocardium. Newer machines perform all these

image optimization procedures automatically just by pressing an

optimization button.

Maximize the frame rate (which determines resolution) while filling the

screen with all required information. This can be done by adjusting depth

to just behind the heart (or area of interest) and reducing sector width to

the area being studied (particularly important for colour flow mapping

and tissue Doppler, which reduce frame rate when switched on but,

perversely, require relatively high frame rates to be useful.)

CHAPTER 2 Transthoracic examination

2D image acquisition

Standard acquisition

Images are acquired in a standard way—with a set sequence of views.

The standard views should always be collected to ensure comprehensive

data collection, with additional views when necessary. Even when there

is a specific question a full dataset should be acquired to ensure nothing

is missed.

Windows

There are 3 key areas or ‘windows’ on the chest and abdomen to collect

standard images (with additional windows available if needed) (Fig. 2.1). It

is normal to image through each window in turn starting with parasternal

windows. However, it may be necessary to go back to windows as pathol-

ogy is found that needs more detailed study.

1. Parasternal window

This window is usually just to the left of the sternum around the 3rd or 4th

intercostal space. However, the best position for parasternal views varies

with each patient. To find the best window move the probe up or down

an intercostal space, and away from or towards the sternum.

2. Apical window

As the name suggests this is at the cardiac apex so normally will be at the

bottom, left, lateral point of the chest. The apex beat may be felt under

the probe. The window should, ideally, be from the true apex to avoid

foreshortening. To optimize, ensure probe is lateral enough and move up

or down an intercostal space.

3. Subcostal window

This lies below the xiphisternum in the epigastrium. Lie the patient on

their back with stomach relaxed (may be easier if the patient bends their

legs). Place probe on the abdomen, press it in and point it back up into the

chest so that the image plane tucks under the ribs.

Additional windows

Suprasternal window

This is the suprasternal notch. Lie the patient on their back and raise the

chin. Rest the probe in the notch and point it down into the chest.

Right parasternal window

This is often used to look at flow in the ascending aorta. A normal or a

stand alone probe can be used. The patient should roll all the way over to

lie on their right side. The window is on the right of the sternum usually

slightly higher than the equivalent left parasternal window.

Supraclavicular window

This is rarely needed but can be used to look at vascular structures and

the aorta. It lies above the clavicles.

2D IMAGE ACQUISITION

Suprasternal

Parasternal

Right

parasternal

Apical

Subcostal

Fig. 2.1 Standard windows for transthoracic echocardiography.

Standard sequence of views

Parasternal windows

• Parasternal long axis view

• (Optional—parasternal right ventricle inflow)

• (Optional—parasternal right ventricle outflow)

• Parasternal short axis view (apex)

• Parasternal short axis view (papillary level)

• Parasternal short axis view (aortic level)

• (Optional—right parasternal window).

Apical window

• Apical four chamber

• Apical five chamber

• Apical two chamber

• Apical three chamber.

Subcostal window

• Subcostal long and short axis

• Inferior vena cava

• (Optional—aorta view).

Suprasternal window

• (Optional—aorta view).

CHAPTER 2 Transthoracic examination

3D image acquisition

3D acquisition differs in that it is used to supplement data collection to

answer questions raised by 2D imaging. The windows selected are chosen

to optimize data collection for a particular area of the heart. The probe is

placed in the same positions on the chest as for 2D acquisition.

Windows

Apical window

The apical window is the main window used for 3D left and right ventricu-

lar acquisition. The setup of the image is nearly always the same as for 2D

imaging with a need to identify the true apex. The probe can be altered to

focus either on the right or left ventricle.

The apical window can also be used to evaluate the aortic, mitral, and

tricuspid valves (Fig. 2.2).

Parasternal window

This is used in 3D echocardiography to acquire 3D datasets of the left ven-

tricle, mitral, aortic, and tricuspid valves (Fig. 2.3). The window is found the

same way as for 2D imaging as the 3D dataset is set up based on biplane

2D imaging. However, often modified parasternal windows are required in

order to focus on a particular area of the heart, e.g. the tricuspid valve.

3D image optimization

When acquiring real-time 3D full volume datasets the following steps

will help to optimize the final image:

• A good ECG signal with clear R wave is necessary to allow 3D full

volume triggering.

• Adjust the scanner settings (as you would do for 2D imaging) to get

the best 3D resolution:

• Adjust gain setting.

• Ensure the region of interest is within the 3D volume sector.

• Minimize the sector (angle and depth) to focus on region of

interest.

• Maximize the number of subvolumes according to patient breath

holding capability.

• Select appropriate line density—the higher densities allow better

resolution although at the expense of a narrower angle sector.

• Optimize the volume size. All commercial scanners allow the final

volume size to be adjusted slightly which may be beneficial in

certain circumstances (e.g. dilated cardiomyopathy).

• Acquire images with the probe maintained in a steady position

and at end expiration.

Following acquisition, review image to look for any stitch artefacts.

When happy with the image then accept the acquisition.

CHAPTER 2 Transthoracic examination

Multiplane image acquisition

Biplane imaging

• Commercial scanners allow the ability to view the image which is being

acquired in two planes. Classically this has been used to assess left

ventricular volumes and ejection fraction.

• Initially an optimal 4 chamber view of the left ventricle is acquired.

When in biplane mode the orthogonal view (i.e. 2 chamber is shown in

a split screen).

• Biplane has the advantage of maintaining the same probe position

for the acquisition of both the 4 chamber and 2 chamber views thus

reducing errors which may occur due to the use of different probe

positions.

• Biplane echocardiography also has the advantage of viewing the target

from 2 planes and so ensuring that foreshortening can be minimized.

Triplane imaging

• Recently, triplane imaging has allowed the target volume to be

acquired and simultaneously viewed from 3 different orthogonal

planes.

• When acquiring a 4 chamber view of the LV in triplane mode, the LV

2 chamber and 3 chamber views are simultaneously displayed (Fig. 2.4).

xPlane and iRotate

These modes available on Phillips echocardiography systems allow differ-

ent planes selected by the operator to be imaged simultaneously from one

acoustic window with a fixed probe position.

• X-plane: This has the advantage of being able to compare directly two

individual planes side-by-side with the primary image displayed on

the left and the secondary image selected by the operator (Fig. 2.5)

displayed next to it.

• iRotate: In this technique the operator can alter the angle of the plane

being viewed without moving the probe, using the controls on the

machine, similar to changing the plane in TOE imaging.

CHAPTER 2 Transthoracic examination

Data acquisition

Techniques for each view

In each view, start the study with 2D imaging and then consider whether

further echocardiography techniques are required to document the find-

ings. Although a standard minimal dataset acquisition (b p.96) is vital, it is

equally important that you analyse and interpret the images as you do the

study. It is easy to save a standard set of images for later analysis but if you

only notice pathology after the study you will not have acquired the right

images. The preliminary analysis needed to search and identify pathology

should be done during the study with detailed confirmation during later

reporting. Consider in each view:

• Colour flow mapping

• M-mode

• CW Doppler

• PW Doppler

• Tissue Doppler imaging

• Speckle tracking imaging

• 3D imaging

• Contrast imaging.

In all views 2D and colour flow mapping are used. Most views also use

CW and PW Doppler as well as occasional M-mode. In some views 3D,

contrast and tissue Doppler imaging may be needed.

Image storage

• All images and data must be stored for future reference. With

the current ease of storage it is no longer acceptable to perform

an echocardiogram and only keep handwritten notes, even in

emergencies.

• Images are usually stored and commonly then transferred directly to a

main server. Digital storage is usually based on storing a single cardiac

cycle loop, triggered off the ECG trace. If the patient has an arrhythmia

with variable cardiac cycle length then it may be better to store 3-5

beats.

• It is desirable to have a digital laboratory to store all acquired views.

Storage on digital media enables better post-processing and follow-up

comparisons.

Formats

• The current preferred means of storage of studies is Digital Imaging

and Communications in Medicine (DICOM). DICOM defines the way

in which patient data is stored, transported, and retrieved.

• For movie storage image acquisitions can be stored commonly as AVI

or MPEG formats.

• Widely used formats for still screen/non-movie storage for use in

presentations include BMP, TIF, and JPEG.

CHAPTER 2 Transthoracic examination

Parasternal long axis view

The first view. Gives an immediate over all impression of the major valves,

left and right ventricle, aorta, and pericardium (Fig. 2.6).

Finding the view

• In the parasternal window hold the probe with the dot pointing to the

right shoulder. Adjust probe with slight rotation and rocking.

• The optimal image cuts through the middle of mitral and aortic valves

to display left ventricular inflow and outflow. Left ventricular walls lie

parallel and straight across screen (anterior border of septum should

be same distance from transducer as anterior wall of ascending aorta).

Ascending aorta should be a tube with parallel walls.

• Sometimes not all structures can be aligned in a single view, in this

situation record several views focused on each detail.

What to record?

• 2D images.

• Colour flow: aortic valve, left ventricle outflow tract, mitral valve.

• M-mode: aortic valve/left atrium, mitral valve, left ventricle.

What do you see?

Left ventricle: septum (anteroseptal portion), inferolateral (also some-

times called posterior) wall and cavity are seen. Use 2D (and M-mode)

to assess left ventricle size, function, and hypertrophy. Also excellent for

LV outflow tract size measurements and evidence of flow acceleration on

colour flow. Septal defects may be seen with colour flow.

Aortic valve: right coronary cusp is at top and non-coronary cusp at bot-

tom. 2D and M-mode can assess movement. Colour flow demonstrates

regurgitation.

Aortic root: entire aortic root, including sinuses, sinotubular junction, and

ascending aorta should be visible for measurement with 2D or M-mode.

Ascending aorta: slight adjustment by rocking the probe to one side can

bring the proximal portion of the ascending aorta into view.

Descending aorta: seen in cross-section as a circle behind mitral valve. Use

as landmark for studying pericardial and pleural fluid.

Mitral valve: A2 and P2 segments usually seen. 2D will pick up move-

ment (prolapse, stenosis, etc.) and tip movement can be documented with

M-mode. Use colour flow to identify regurgitation. Vena contracta or flow

convergence may be evident.

Left atrium: left atrial size can be judged and measured with M-mode.

Right ventricle: the right ventricle lies near the probe and can be measured.

Pericardium: seen anteriorly in front of right heart and posteriorly behind

heart. Good view to identify an effusion and measure size.

CHAPTER 2 Transthoracic examination

Parasternal right ventricular inflow view

A useful extra view to look at tricuspid valve and right ventricular inflow

(Fig. 2.7).

Finding the view

• From parasternal long axis view, rock probe slowly to point

downwards. The tricuspid valve should come in to view. There usually

needs to be some slight rotation to optimize the image.

• Optimal images demonstrate the tricuspid valve with right atrium

behind and sometimes vena caval inflow.

What to record?

• 2D image.

• Colour flow across the tricuspid valve.

• CW and PW Doppler across the tricuspid valve.

What do you see?

• Tricuspid valve: main feature. Two leaflets seen in centre of screen. Use

colour flow to document regurgitation. Jet may be aligned for Doppler

measures of inflow and right ventricular systolic pressure.

• Right atrium: lies behind tricuspid valve and slight rotation may

demonstrate right atrial appendage, Eustachian valve and inflow from

vena cavae.

• Right ventricle: portion of right ventricle close to tricuspid valve seen.

Parasternal right ventricular outflow view

A useful extra view to look at pulmonary valve and artery (Fig. 2.7).

Finding the view

• From parasternal long axis view, rock probe slowly to point upwards.

Pulmonary valve should come into view. Slight rotation will optimize

image to include pulmonary artery.

• Optimal image demonstrates the pulmonary valve with pulmonary

arterial trunk to bifurcation.

What to record?

• 2D image.

• Colour flow pulmonary valve.

• Continuous and pulsed wave Doppler across pulmonary valve.

What do you see?

• Pulmonary valve: main feature. Two leaflets seen in centre of screen.

Use colour flow to document regurgitation. Jet normally aligned for

Doppler measures of outflow and regurgitation.

• Pulmonary artery: in the far field. With slight adjustments can usually be

followed to bifurcation. Can measure size and look for abnormal jets

(patent ductus) or thrombus (pulmonary embolus).

CHAPTER 2 Transthoracic examination

Parasternal short axis (aortic) view

A series of parasternal short axis views are gathered in order to scan

through the heart in cross-section. Together they give an impression

of left ventricular function, aortic and mitral structure, and the right heart

(Fig. 2.8).

Finding the view

• From the parasternal long axis view, rotate the probe around 90º so

that the dot points to the left shoulder. Try and rotate from a long axis

view with the aortic valve in the centre. Focus on keeping the valve

in the centre and you should end up with the classic cross-section

through the aortic valve.

• It can be difficult to get a true on-axis cut. To optimize the image try

slight rotation around the point until the aortic valve appears circular

with the right ventricle wrapped around the valve. Then rock the

probe back and forward until the cut is straight.

• Optimal image should have a round aortic valve with 3 cusps evident.

The tricuspid valve should be visible on the left and pulmonary valve

on the right.

• If all structures are not seen remember to record several views

focused on each detail.

What to record?

• 2D images.

• Colour flow: aortic, tricuspid, and pulmonary valve (also sometimes

atrial septum).

• Doppler: pulmonary and tricuspid valve.

What do you see?

• Aortic valve: lies in centre with classic Y-shape: left coronary cusp on

right, right towards the top, and non-coronary on the left. Use colour

flow to identify regurgitation. Left main stem sometimes seen by left

cusp.

• Right ventricle: basal right ventricle lies near the probe wrapped around

aortic valve. Ventricle can be measured.

• Tricuspid valve: seen to left of aortic valve. Use colour flow to check

for regurgitation. May be aligned for CW Doppler.

• Pulmonary valve: to right of aortic valve. Colour flow demonstrates

regurgitation. CW and PW Doppler will document velocities.

• Left atrium: lies behind aortic valve.

• Interatrial septum: septum lies at 7 o’clock and view may be useful to

identify septal defects with colour flow.

• Pericardium: seen anteriorly, in front of right heart.

CHAPTER 2 Transthoracic examination

Parasternal short axis (mitral) view

The classic en face or ‘fish-mouth’ view of the mitral valve (Fig. 2.9).

Finding the view

• From the parasternal short axis aortic view, rock the probe slightly

towards the cardiac apex. By starting the parasternal cuts from the

aortic valve the views tend to stay ‘on-axis’.

• Optimal image should have a left ventricle with the ‘fish mouth’ mitral

valve clearly seen.

What to record?

• 2D images. Consider 2D planimetry if stenosis.

• Consider colour flow across mitral valve, if regurgitation.

What do you see?

• Mitral valve: a classic en face view of the mitral valve to look at valve

morphology (including the separate scallops) and movement. Consider

colour flow or 3D imaging if abnormalities. Can also be used to

measure valve opening with planimetry.

Parasternal short axis (ventricle) views

The classic short axis views of the left ventricle (Fig. 2.9).

Finding the view

• From the parasternal short axis mitral view, rock probe slightly more

towards apex until left ventricle is in cross-section. The papillary level

has the bodies of both papillary muscles evident.

• Further rocking towards apex creates an apical view distal to papillary

muscles.

• Usually important to avoid off-axis images so that true assessment of

left ventricle function is possible. Slight rotation helps bring out the

circular ventricular shape. If it is proving very difficult to get a clear

image consider moving the probe position slightly within the window.

• Optimal images should have a cross-section of the left ventricle.

What to record?

• 2D images at papillary level for measures: left ventricle size and mass.

• Consider a view recorded at apical level.

• Consider M-mode measures: left ventricle.

• Tissue Doppler imaging sometimes used in short axis.

• Speckle tracking imaging.

What do you see?

• Left ventricle: the short axis demonstrates septum, anterior, lateral, and

inferior walls (in order clockwise). Use for measures of left ventricle size

and thickness and to assess regional function of mid segments of walls.

• Right ventricle: right ventricle is seen as a crescent around the

left ventricle. Use to judge right ventricle size, function, and

haemodynamics.

CHAPTER 2 Transthoracic examination

Parasternal 3D views

Finding the view

• The initial window is located in a similar fashion as for 2D acquisition

with the probe marker pointing towards the right shoulder and the

probe positioned in the 3rd or 4th intercostal space.

• Slight probe adjustment either laterally or medially to the sternum

or manoeuvring the probe to an adjacent intercostal space will help

identify the optimal position for acquisition.

What to record?

• Left ventricle full volume acquisition.

• Mitral valve full volume or live 3D acquisition.

• Mitral valve colour Doppler acquisition.

• Aortic valve full volume and/or live 3D acquisition.

• Aortic valve colour Doppler acquisition.

What do you see?

Similar anatomical landmarks can be appreciated as in the

2D view

(Figs. 2.10 and 2.11). The advantage of 3D acquisition is appreciated fol-

lowing data collection when the dataset can be rotated to see anatomy

(Fig. 2.12) and the spatial associations of different pathologies, e.g. mitral

valve prolapse and the insertion of chordae.

Fig. 2.10

3D live zoom acquisition of the aortic valve (AV) taken from the

parasternal view. The anterior mitral valve leaflet is also seen (AMVL).

See W Video 2.10.

CHAPTER 2 Transthoracic examination

Apical four chamber view

Finding the view

• In the apical window, hold the probe with the dot pointing towards

the couch.

• Probe needs to be as close to the left ventricular apex as possible

so alter the image, focusing on obtaining the optimal Ieft ventricular

size and shape. The identifying characteristics of the apex are that it

moves less than the other walls and is thinner. In a true apical view

the left ventricle will be at its longest. Once you have identified the

apex optimize the view with rotation and rocking to bring in the right

ventricle, left and right atrium, as well as, mitral and tricuspid valves.

Exclude the left ventricular outflow and aortic valve by tilting the probe.

• Optimal image should be at apex with both ventricles, both atria and

both mitral and tricuspid valves visible. Septa should be straight down

the centre of the image.

What to record?

• 2D images.

• Colour flow mapping: mitral and tricuspid valves.

• CW and PW Doppler: mitral and tricuspid valve.

• Consider Doppler of right upper pulmonary vein.

• Consider tissue Doppler imaging of right and left ventricle.

• Speckle tracking.

• 3D datasets.

• When appropriate use contrast.

What do you see ? (Fig. 2.13)

• Mitral valve: A2 and P2 segments of mitral valve are seen. 2D for

movement. Colour flow mapping will show regurgitation (vena

contracta, flow convergence, etc.) Doppler well aligned for stenosis

and valve inflow. Tissue Doppler of lateral and septal sides of mitral

ring may be possible.

• Tricuspid valve: lateral and septal leaflets displayed. As for mitral valve,

colour flow, Doppler and tissue Doppler are possible.

• Left and right atrium: both atria and the interatrial septum can be

seen. Pulmonary veins as well as vena cavae may be seen in far field.

Use to measure atrial volumes.

• Left ventricle: key view to study global and regional left ventricle

function. Septum, apex, and lateral wall are displayed. Good for

2D volume measures if endocardial border is clear. If assessing

left ventricle function consider contrast and/or 3D to improve left

ventricle data collection. Tissue Doppler of different wall segments is

also possible.

• Right ventricle: a key view to look at right ventricle size and function.

Usually compared relative to left but also tissue Doppler or M-mode

of tricuspid free wall annulus can be considered.

• Pericardium: important view to see size and location of pericardial

fluid. May also be used for ultrasound-guided pericardiocentesis.

CHAPTER 2 Transthoracic examination

Apical five chamber view

Used to look at left ventricular outflow and aortic valve (Fig. 2.14).

Finding the view

• From the apical four chamber view tilt the probe to bring the aortic

valve and outflow tract into view.

• Sometimes a better alignment through aortic valve and ascending aorta

is obtained by moving probe laterally on chest wall (more into axilla).

• This foreshortens left ventricle and alters alignment for other valves so

use only to study the aortic valve.

• Optimal image looks similar to apical four chamber but with the aortic

valve evident and ascending aorta in far field.

What to record?

• 2D images.

• Colour flow mapping: aortic valve.

• CW and PW Doppler: aortic valve and left ventricle outflow tract.

What do you see?

• Aortic valve: right and non-coronary cusps (although may not be easy

to see). Colour flow demonstrates regurgitation. CW for stenosis and

regurgitation.

• Left ventricular outflow tract: use colour flow mapping for aortic

regurgitation or flow turbulence due to obstruction. Best view to place

PW Doppler to assess outflow and obstruction.

CHAPTER 2 Transthoracic examination

Apical two chamber view

An important view for global and regional left ventricular assessment

(Fig. 2.15).

Finding the view

• From the apical four chamber view, rotate the probe around 90º

anticlockwise. Watch the picture and try and keep the mitral valve in

place. If the apex of the ventricle changes you were probably not at

the apex and are foreshortening.

• Keep rotating until right ventricle disappears completely but before left

ventricular outflow tract comes into view.

• Optimal image contains left ventricle (no right ventricle) from apex,

centred in the image. Mitral valve is cut through the commissure. Left

atrium is in far field and left atrial appendage may be visible.

What to record?

• 2D images.

• Consider Colour flow and Doppler measures across mitral valve.

• Consider tissue Doppler imaging of ventricle.

What do you see?

• Left ventricle: inferior wall on left, and anterior wall on right. Good

for regional assessment. Use plane for ventricle volume measures and

tissue Doppler of wall segments.

• Mitral valve: ideal image is of a commissural view with P3, A2, and P1

segments visible from left to right. Colour flow and Doppler measures

are possible as well as assessment of the long axis of the mitral valve

ring.

• Left atrial appendage: sometimes visible as a curved finger pointing

towards probe around right side of mitral valve.

• Coronary sinus: the coronary sinus is usually seen in cross-section on

the left of the mitral valve.

Adaptation of view

• Right ventricle: slight tilting of probe to point forwards can scan into a

two chamber view of right ventricle (not a standard view).

CHAPTER 2 Transthoracic examination

Apical three chamber view

Similar to the parasternal long axis view but includes left ventricular apex

(Fig. 2.16).

Finding the view

• From the apical two chamber view continue rotating the probe

anticlockwise to around 135º from the four chamber view.

• Watch the picture and keep the mitral valve in place, rotating until

the left ventricle outflow and aortic valve come into view. As for the

translation from four to two chamber.

• Optimal image contains left ventricle from apex straight down the

screen with mitral valve, left atrium, left ventricle outflow, and aortic

valve in far field.

What to record?

• 2D images.

• Consider tissue Doppler and speckle tracking imaging of ventricle.

• Consider colour flow and Doppler measurements across aortic valve

as may be well aligned.

• Consider colour flow and Doppler measures across mitral valve.

What do you see?

• Left ventricle: good view to assess septum on right of image, apex and

inferolateral (posterior) wall on left of image.

• Aortic valve: right coronary cusp is on right and non-coronary cusp on

left. Colour flow will demonstrate regurgitation and valve is usually

aligned for Doppler measurements.

• Mitral valve: A2 and P2 segments of valve seen and can consider

colour flow and other Doppler measures if not enough detail from

other views.

• Left atrium: atrium lies behind mitral valve.

CHAPTER 2 Transthoracic examination

Apical 3D views

Finding the view

• The initial window is located in a similar fashion as for 2D acquisition

of the apical four chamber view (see b p. 78).

What to record?

• Left ventricle full volume acquisition.

• Right ventricle full volume acquisition.

• Mitral valve full volume and live 3D acquisition.

• Mitral valve colour Doppler acquisition.

• Aortic valve full volume and live 3D acquisition.

• Aortic valve colour Doppler acquisition.

• Tricuspid valve full volume and live 3D acquisition.

• Tricuspid valve colour Doppler acquisition.

What do you see?

Similar anatomical landmarks can be appreciated as in the

2D view

(Fig. 2.17). Following data acquisition, the 3D image can be rotated to

make it easier to understand how any pathology relates to the different

parts of the heart.

CHAPTER 2 Transthoracic examination

Subcostal views

Very useful views to study pericardial effusions, assess right ventricular

inflow, and screen for septal defects (Fig. 2.18). Also, alternative window

for equivalent of parasternal views if parasternal window not possible.

Finding the view

• In the subcostal window have the probe flat and pressed into the

stomach so that the imaging plane is directed upwards under the ribs.

• With slight rotation and tilting back and forward you will find the

heart. You will need to increase the depth. If it is difficult to get an

image, ask the patient to take a breath in. This drops the diaphragm

and often brings the heart into view. Once you have found the heart

optimize the image with gentle movements of the probe.

• Optimal image will look like a four chamber view but from the side.

Both ventricles and both atria should be seen with the atrial and

ventricular septa aligned horizontally across the screen. Both mitral

and aortic valves should be evident.

• The probe can also be rotated 90º in this view to create a short axis

subcostal view. By tilting back and forward this can be used to look at

left and right ventricle and pulmonary valve.

What to record?

• 2D images.

• Colour flow mapping: tricuspid valve and septa (atrial and ventricular).

What do you see?

• Right ventricle: close to probe and both free wall and septum are seen.

Wall thickness can be measured. The septum is flat across the screen

so good alignment for colour flow mapping of septal defects.

• Right atrium: good view to look at right ventricle inflow as close

to probe. May see Eustachian valve and entry of inferior vena cava.

Because of horizontal alignment of interatrial septum an ideal view for

colour flow mapping of atrial septal defects and Doppler alignment to

quantify flow across defects.

• Tricuspid valve: close to probe and can be used for colour flow

mapping of regurgitation.

• Pericardium: excellent view to assess size and depth of effusion when

planning pericardiocentesis as probe in position of a subxiphisternum

approach.

• Left ventricle: in far field. Septum and lateral wall are seen.

• Mitral valve: in far field and little extra information provided.

• Left atrium: little extra information provided about left atrium.

CHAPTER 2 Transthoracic examination

Inferior vena cava view

Essential to assess right atrial pressure (Fig. 2.19).

Finding the view

• From the subcostal view rotate the probe anti-clockwise.

• Keep the right atrium in the centre of the image and focus on the

atrium as you rotate the probe. The opening of the inferior vena cava

should become more obvious. As you rotate the probe the vena cava

should open out into a long tubular structure horizontally across the

screen. If you are worried it may be the aorta, not the vena cava, use

pulsed wave Doppler to demonstrate continuous, low velocity venous

flow rather than pulsatile, high velocity aortic flow.

• Optimal image is of the vena cava like a railway track across the screen

perhaps seen opening into right atrium. Hepatic veins emptying into

vena cava may also be seen.

What to record?

• 2D images with inspiration and expiration (a 5-beat loop may be

required).

• M-mode measures with respiration.

• Consider pulsed wave Doppler in aligned hepatic veins.

What do you see?

• Inferior vena cava: use to measure diameter and whether it reduces in

size with inspiration (normally should do).

• Liver and hepatic veins: these can be seen draining into the vena cava

and may be aligned for Doppler measures. If right atrial pressures are

high they may be dilated.

Abdominal aorta view

Not an essential view but interesting (Fig. 2.19)! A simple screening test

for aortic aneurysm.

Finding the view

• From the subcostal inferior vena cava view tilt the probe out of the

plane of the inferior vena cava. The aorta should come into view and

look very similar to the vena cava. It usually lies to the left of the vena

cava and slightly deeper. Confirm it is aorta with PW Doppler to

demonstrate arterial flow.

• Optimal image is of the aorta like a ‘railway track’ across the screen.

What to record?

• 2D images.

What do you see?

• Aorta: may see wall thickening, aneurysm or even gross mobile

thrombus and plaque.

CHAPTER 2 Transthoracic examination

Suprasternal view

A view to look at size of aorta and aortic flow for coarctation or aortic

regurgitation (Fig. 2.20).

Finding the view

• In the suprasternal window have the probe pointing, slightly rotated,

into the chest behind the sternum. The dot on the probe should

be towards the left shoulder. Use light pressure (with extra gel to

maintain contact between probe and skin if necessary) as it can be

uncomfortable.

• Tilt probe back and forward until the arch comes into view then rotate

to maximize the curve of the arch. Colour flow may help identify flow

in the aorta.

• Optimal image has distal ascending aorta, arch, and proximal

descending aorta with origin of the left subclavian on the right, and

potentially origin of left carotid and brachiocephalic.

What to record?

• 2D images.

• Doppler of flow in ascending and descending aorta.

• Consider colour flow mapping around arch and subclavian artery

(looking for jets associated with patent ductus arteriosus, coarctation

or obstruction).

What do you see?

• Aortic arch: curves through picture and can be measured.

• Ascending aorta: can be difficult to see clearly but can provide

alignment for CW Doppler measures in aortic stenosis.

• Descending aorta: usually better seen than ascending aorta. Size can

be measured and is aligned for Doppler studies of aortic flow to grade

aortic regurgitation or coarctations.

• Left subclavian artery: easiest branch to see and important landmark

for isthmus (common site of dissection and coarctation).

CHAPTER 2 Transthoracic examination

Right parasternal view

An extra view to look at ascending aorta and judge severity of aortic

stenosis but can be difficult to find (Fig. 2.21).

Finding the view

• Roll patient over onto right side. Place probe on right side of sternum

pointing down and under sternum (both stand alone and 2D probes

can be used).

• Adjust probe in all directions looking for Doppler across aortic valve

and up ascending aorta. If using stand alone Doppler probe look for

the aortic spectral pattern and if using a 2D probe use colour flow

mapping to identify ascending aorta. Once a signal has been found

keep adjusting probe position until maximal Doppler signal.

• Optimal image has ascending aortic flow aligned with probe.

What to record?

• 2D images with colour flow to demonstrate aorta.

• CW Doppler of flow through aortic valve.

What do you see?

• Ascending aorta: often little to see but can be very useful for a second

measure of an aortic gradient if there is concern that it is being

underestimated. The alignment of flow through the aortic valve for

Doppler measures is often better in the right parasternal view than the

apical or suprasternal views.

CHAPTER 2 Transthoracic examination

Standard examination

The minimal sequence of views and measurements needed to perform

a study can be standardized to ensure collection of a minimal dataset.

Minimal datasets are published by bodies of experts as a guide to what

information should be collected.

A graphic description of a standard examination in the order of data col-

lection is given in Figs. 2.22–2.29.

Quality of echocardiographic recordings

The quality of echocardiographic recordings is based on:

• Is the dataset complete i.e. a full standard examination and minimal

dataset?

• Are all the recordings obtained from the appropriate imaging points,

i.e. correct apical position etc.?

• Is image quality good, i.e. are the views appropriately recorded,

correct gain and depth, etc.?

Image quality

2D/3D imaging is best judged on endocardial border definition. Look at

the proportion of the border that is clearly seen in the 3 apical views.

Judge image quality as:

• Good if >80% of the border is seen in the 3 apical views.

• Poor if the endocardium is not visible.

• Image quality is moderate if endocardial border is visible but <80%.

For stress echocardiography good image quality is required and

there should be a maximum of 2 segments not seen in any view.

Spectral Doppler should be judged as:

• Good if the cursor position is displayed, there is good alignment

(with the angle between flow and beam <30º) and the spectrum has

a clear envelope.

• Poor if the angle between flow and beam is >30º or the spectrum is

incomplete.

• Only good spectral Doppler tracing should be used for quantitative

analysis.

Colour flow mapping should be judged as:

• Good if the flow of interest is aligned with the probe and gain

settings are correct (just below the level that produces background

noise). If for flow convergence, the baseline has been shifted.

• Poor if the flow is not aligned or gain settings are incorrect.

• For assessment of regurgitation colour flow mapping must be good.

When used to align spectral Doppler then suboptimal settings may be

sufficient.

105

Chapter 3

Transthoracic anatomy

and pathology: valves

Mitral valve

106

Mitral stenosis

110

Mitral regurgitation

116

PISA (proximal isovelocity surface area) 126

Mitral valve prolapse

128

Aortic valve

132

Aortic stenosis

134

Aortic regurgitation

142

Bicuspid and quadricuspid valves 152

Lambl’s excresences 152

Tricuspid valve

154

Tricuspid regurgitation

156

Right heart haemodynamics 162

Tricuspid stenosis

164

Tricuspid valve surgery

166

Carcinoid syndrome 166

Infective endocarditis

166

Ebstein anomaly 166

Pulmonary valve 168

Pulmonary regurgitation 170

Pulmonary stenosis 174

Mechanical prosthetic valves 176

Bioprosthetic valves

180

Prosthetic valve abnormalities

182

Prosthestic valve stenosis

184

Prosthetic valve regurgitation

186

Endocarditis 188

106

CHAPTER 3 Transthoracic valves

Mitral valve

Normal anatomy

The mitral valve has two leaflets (anterior and posterior). The posterior

is long and thin, and forms a crescent around the wider anterior leaflet.

The surface area of both leaflets is approximately equal but the distance

between mitral ring and coaption line is shorter on the posterior leaflet.

Each leaflet has 3 scallops which meet each other along the coaption line.

They are named: A1, A2, A3 (anterior) and P1, P2, P3 (posterior). P1 and

A1 are adjacent to the anterolateral commissure and A3 and P3 nearest

the right heart. Below the valve are two papillary muscles: a larger ante-

rolateral (usually a single trunk) and a smaller posteromedial (often 2-3

distinct trunks). These support chordae tendinae: 1st order attached to

leaflet tips, 2nd order to undersurface of leaflets, and 3rd order run directly

from ventricular wall to leaflet undersurface. Chordae from both papillary

muscle attach to both leaflets. The valve leaflets are supported by the

mitral valve annulus, which divides the left atrium and ventricle, and is a

fibrous elliptical structure.

Normal findings

2D views

• The mitral valve can be seen in most views (Fig. 3.1). Parasternal long

axis and parasternal short axis (mitral valve level) are particularly

useful to look at valve motion and structure.

• The 3 apical views offer the ability to scan through the mitral valve in

multiple planes and do Doppler measurements.

2D findings

• Parasternal long axis: segments of the anterior leaflet (A2—nearest

the left ventricular outflow tract) and posterior leaflet (P2) are seen

as thin structures uniform in echogenicity. The posteromedial papillary

muscle may be seen attached to the posterior wall.

• Parasternal short axis: at the mitral valve level, all three segments of

each leaflet are seen and the 2 commissures. This creates the classic

‘fish mouth’ appearance. At the mid level of the left ventricle the

bodies of the two papillary muscles can be seen.

• Apical 4-chamber view: the A2 and A1 segments of the anterior leaflet

are shown on the left and the P1 segment of the posterior leaflet on

the right. The mitral valve annulus is usually slightly out of line with the

tricuspid valve annulus (the tricuspid annulus is normally up to 1cm

closer to the right ventricular apex).

• Apical 2-chamber view: the P1 and P3 segments are seen either side of

the A2 segment of the anterior mitral valve leaflet.

• Apical 3-chamber view: the A2 and P2 segments are visualized similar

to the parasternal long axis view.

108

CHAPTER 3 Transthoracic valves

3D views

• Real-time 3D transthoracic imaging is now available and is an excellent

tool in assessment of the mitral valve. Biplane 2D live images are

optimized to ensure accurate probe position to assess the lesion in

question before full volume acquisition.

• The parasternal long axis, parasternal short axis basal ventricular level

and apical 4-chamber views are the most suitable for imaging the mitral

valve in 3D.

• All the 3D acquisitions modes (b p.34) can be used: full volume

datasets/live 3D imaging (Fig. 3.2)/live 3D zoom and 3D colour

Doppler imaging.

• 3D echocardiography findings are enhanced by rotation and cropping

of the 3D volume either after acquisition or during live monitoring.

• This rotation allows the mitral valve to be viewed from multiple

angles and allows for the generation of specialized views such as the

‘surgeons view’. i.e. a view of the mitral valve from the left atrium with

the left atrial appendage on the left and the aorta at the top of the

image.

3D findings

• Use the surgeon’s view to assess all 3 scallops of the anterior and

posterior leaflets.

• 3D mitral valve reconstruction and post-processing also allows the

unique shaped curvature of the mitral valve to be modelled for precise

measures of annulus size, extent of prolapse, etc.

110

CHAPTER 3 Transthoracic valves

Mitral stenosis

General

The commonest cause of mitral stenosis is still rheumatic disease. Systemic

lupus erythematosus is a rare cause and congenital mitral stenosis is very

rare. Clinically, atrial myxoma and cor triatriatum may mimic mitral ste-

nosis. Mitral annular calcification is common in the elderly and can involve

the entire posterior part of the annulus. Occasionally annular calcification

can extend to the base of the leaflets leading to stenosis but more com-

monly leads to regurgitation.

Assessment

• Echocardiography should be used to diagnose stenosis and describe

probable aetiology based on appearance.

• Severity should be graded according to: valve area; pressure gradient

across the valve; changes to left atrium, left ventricle, and right heart.

• The examination should also be used to look for associated valvular

lesions (in particular rheumatic aortic disease) and complications such

as endocarditis.

Appearance

Comment on the valve:

• Mobility of base of leaflet compared to tips. In rheumatic disease the

tips tend to be restricted so the valve appears to ‘dome’. This may also

be referred to as a ‘hockey stick’ or’elbowing’ appearance (Fig. 3.3).

• Thickening or calcification of leaflets, annulus and subvalvular apparatus.

• Evidence of fusion of the commissures. Use a short axis view.

• Chordae—thickening, shortening, calcification.

Comment on associated features:

• Associated valvular lesions (aortic rheumatic disease).

• Left atrium:

• Usually grossly enlarged. Give measurement.

• Spontaneous left atrial contrast (associated with significant stenosis

and suggests very slow atrial blood flow or stasis).

• Right heart:

• Tricuspid regurgitation and right ventricular pressure.

• Right ventricle and atrial size.

• Left ventricular function.

Differentiation of rheumatic mitral stenosis from

calcification

In rheumatic disease (in contrast to degenerative mitral valve disease):

• Thickening comes first with calcification later.

• Leaflet thickening affects the commissures and leaflet edges whereas

mitral annular calcification tends to spare the leaflet tips.

• There is subvalvular involvement with shortening of chordae.

• Combination of loss of leaflet mobility due to commissural fusion

and chordal shortening and tethering leads to ‘doming’ or ’hockey-

stick’ appearance of, in particular, the anterior leaflet.

112

CHAPTER 3 Transthoracic valves

Grading of mitral stenosis

• Grade stenosis as mild, moderate, or severe based on valve area

(Table 3.1). Use planimetered measurements and pressure half-time

across the valve. Also, report the actual measures.

• Back this up with assessment of pressure gradient across the valve.

• Comment on associated changes that support your assessment.

Include changes to the left atrium and right-sided pressures.

Planimetry: 2D

• In parasternal short axis view, angle the probe to the mitral valve level.

• Move the probe back and forth until you are sure you are at the

level of the leaflet tips. If the plane is too basal, stenosis will be

underestimated.

• Record a loop and scroll through to find the maximum opening in

diastole (Fig. 3.4).

• Trace along the inner edge of the leaflets. This may be difficult in

heavily calcified valves so comment if there is a lot of calcification.

• Report the surface area of the orifice.

3D in assessment of mitral stenosis

3D transthoracic echocardiography (Fig. 3.5) is more accurate, quicker

and reproducible than 2D for planimetered measures because it is easier

to be confident you have the smallest area. To planimeter mitral valve

area in 3D:

• Optimize a 3D view from the parasternal short axis mitral valve

level. Using this view reduces distance between probe and valve, so

will improve resolution.

• Ensure the volume includes the ‘mouth’ of the mitral valve to ensure

planimetry of the stenosis is possible.

• Acquire a volume dataset and then use postprocessing software

such as QLAB (Philips) to identify the 2D plane that cuts through the

mitral leaflet tips. Then trace around the inner edge of the leaflets as

for 2D imaging.

• Report the surface area of the orifice.

Problems with planimetry

• Planimetered mitral area methods are useful as they are not affected

by haemodynamic changes but can overestimate size if the tips of the

leaflets are not identified.

• It is important when estimating the planimetered area that the

optimal plane is used to ensure that the smallest area from the

leaflets free edge is traced.

114

CHAPTER 3 Transthoracic valves

Pressure half-time

• In the apical 4-chamber view get a good view of the mitral valve.

• Align continuous wave Doppler with the inflow jet through the

stenosis. Try and minimize any angle between the beam and the jet.

• Record a spectral trace and measure the slope of the diastolic flow

across the valve (Fig. 3.6).

• Use the E-wave if both E-wave (diastolic filling) and A-wave

(atrial systole) are present (often there is no A-wave because the

patient is in atrial fibrillation). If the trace is slightly curved with a

steep start (a ’ski-slope’). Ignore the start and use the flatter portion.

• The machine automatically reports pressure half-time and mitral valve

area. The relation between these measures is simple:

Mitral valve area in cm

220/pressure half-time

in ms

Mean transmitral valve diastolic pressure gradient

• Use the same technique/recording as used for pressure half-time.

• Trace the Doppler profile of the transmitral diastolic flow. The

machine automatically reports the mean pressure gradient.

• Pressure gradient varies significantly with the filling time. If the patient

is in atrial fibrillation this will vary so report the mean of 2-3 beats.

Problems with pressure half-time and pressure gradient

• Quantification based on pressure half-time assumes normal left

ventricle pathophysiology. Significant changes in left ventricular

compliance (e.g. left ventricular hypertrophy) or pathology that

increases left ventricular pressure during diastole (e.g. aortic

regurgitation) shorten the pressure half time. Valve area is

overestimated.

• Normal atrial pathophysiology is also assumed. An atrial septal

defect with left-to-right shunt shortens the pressure half time

(as blood also leaves from left to right atrium) and valve area is

overestimated. Conversely a right-to-left shunt will lengthen the

pressure half time.

116

CHAPTER 3 Transthoracic valves

Mitral regurgitation

General

Mitral regurgitation is common. A trace of ‘physiological’ mitral regur-

gitation is seen in up to 50% of people with normal cardiac anatomy.

Pathological mitral regurgitation can be caused by changes in the leaflets

(e.g. endocarditis, myxomatous change), subvalvular apparatus (e.g. papil-

lary muscle rupture) or mitral annulus (e.g. left ventricular dilatation).

Assessment

• Mitral regurgitation is easily identified with colour flow placed over the

mitral valve and left atrium in parasternal long axis and apical views.

• Once identified a wider study of the appearance of the valve,

subvalvular apparatus, and left ventricle should be used to determine

aetiology and impact on cardiac function.

• Severity should be judged by combining measurements from all main

Doppler modalities (colour flow, continuous and pulsed wave) and 2D

echocardiography.

Appearance

• Map the regurgitant jet with colour flow in parasternal and apical views

(Fig. 3.7). Establish the shape and pattern. Comment on:

• Where the regurgitation passes through the valve, e.g. central, by a

commissure, or through a perforation.

• The direction of eccentric jets (anterior or posterior). Anteriorly-

directed suggests a posterior leaflet problem and posteriorly-

directed suggests an anterior leaflet problem. Note which left atrial

wall the jet entrains against and how far back it goes.

• If there are several jets, comment on each one.

• Spectral Doppler and colour M-mode can define the timing of

regurgitation e.g. confined to a short period after valve closure

(closing volume) or to late systole (often found in mitral valve

prolapse).

• In parasternal and apical views use M-mode and 2D to look at both

valve leaflets. Comment on:

• Movement, evidence of prolapse, calcification, masses, vegetations.

• Look at subvalvular apparatus. Comment on:

• Papillary muscle and chordae with reference to shortening, rupture.

• Report associated features:

• Left atrial size, left ventricular size and function—important when

considering surgery, any changes to right heart and right ventricular

systolic pressure.

MITRAL REGURGITATION

117

Physiological, mild, or trace (trivial) regurgitation

It is reasonable to decide mitral regurgitation is mild if:

• Jet is small (jet area <4 cm2 or <20% left atrial area) and central.

• No flow convergence zone is displayed.

• Trace regurgitation is a qualitative description that implies ‘not as

severe as mild.’

To call mitral regurgitation physiological make sure:

• Valve morphology is normal.

• The regurgitation has a short duration (typically post valve closure).

• It is mild or trivial.

APICAL FOUR CHAMBER

Anteriorly directed mild

mitral regurgitation

APICAL FOUR CHAMBER

Posteriorly directed moderate

mitral regurgitation

Severe central mitral regurgitation

PARASTERNAL LONG AXIS

Fig. 3.7 Colour flow mapping of mitral regurgitation with eccentric and central jets.

See W Video 3.4, W Video 3.5, W Video 3.6.

118

CHAPTER 3 Transthoracic valves

Grading severity

• Gauge severity as mild, moderate or severe based on the combination

of jet area, vena contracta, flow convergence (PISA) and changes in

systolic pulmonary vein flow (if technically possible) (Table 3.2).

• Gross pathology, e.g. a flail leaflet, points to severe regurgitation.

• Once you have an impression of severity use CW Doppler waveform

density, changes in left ventricular mitral inflow, and left ventricular

function to support your assessment.

• You can provide further quantification of regurgitation with

measurement of effective regurgitant orifice area (EROA), regurgitant

volume, and regurgitant fraction.

Colour Doppler jet area

• Establish an apical image that includes the whole left atrium.

• Using colour flow mapping, optimize the image to include the whole

regurgitant jet. Set Nyquist limit at 50-60cm/s.

• Record a loop and scroll through to reach the frame with the

maximum jet size.

• Trace the regurgitant jet. Trace the border of the left atrium (Fig. 3.8).

If there are multiple jets add the separate jet areas together.

• Report the absolute size of the jet and the size relative to the size of

the left atrium (percentage).

• Grade the severity but bear in mind:

• If the jet area relative to left atrium suggests the regurgitation is

mild or moderate but the left atrium is very large (>70mm2) then

grade it as moderate or severe respectively.

• If the jet area suggests the regurgitation is severe but the

regurgitation is not pansystolic then overall regurgitation may be

moderate.

Problems with jet area to gauge severity

Correlation between jet area and severity of mitral regurgitation is poor

and the measurement should be used only in combination with the

other methods. This is because:

• The regurgitant jet area includes turbulent (aliased) flow signals

as well as laminar velocities in the same direction as the mitral

regurgitation jet. Movement of blood already in the left atrium that

moves with the regurgitant jet (entrainment) is therefore included.

• Jet area can be artificially changed. Reducing the scale increases

the area because the lower filter setting means lower velocities

are displayed. Try and use average scale settings (50-60 cm/s) and

ensure the same setting on follow up scans.

• Eccentric jets are underestimated as they flatten out against walls

and go out of plane.

MITRAL REGURGITATION

119

Table 3.2 Assessment of severity of mitral regurgitation

Specific signs of severity

Mild

Severe

Jet

<4cm2 or <20% left

40% or 10cm2

(Nyquist 50-60cm/s)

atrium; small & central large & central or wall

impinging and swirling

Vena contracta

<0.3cm

>0.7cm

PISA r (Nyquist

None/minimal

Large (>1cm)

40cm/s)

(<0.4cm)

Pulmonary vein flow

Systolic reversal

Valve structure

Flail or rupture

Supportive signs of severity

Mild

Severe

Pulmonary vein flow

Systolic dominant

Mitral inflow

A-wave dominant

E-wave dominant (>1.2 m/s)

CW trace

Soft & parabolic

Dense & triangular

LV and LA

Normal size LV if

Enlarged LV & LA if no

chronic MR

other cause

Report as moderate if signs of regurgitation are greater than mild but there are no features

of severe regurgitation.

Jet area

Left atrium area

Fig. 3.8 Colour jet area and area of left atrium as marker of severity.

120

CHAPTER 3 Transthoracic valves

Vena contracta

• Obtain a clear view of the colour flow through the mitral valve in

parasternal long axis or apical 4-chamber views.

• If necessary, scan along the commissural line to ensure you have the

point of regurgitation through the valve.

• Zoom in on the colour flow through the mitral valve.

• Record a loop and scroll through to identify the image with maximal

flow through the valve.

• The vena contracta is the narrowest region of the regurgitant jet

(usually just below the valve in the left atrium).

• Report the diameter. >0.7cm suggests severe regurgitation.

• A parasternal short axis view just below the mitral valve level can be

used and cross-sectional area of the regurgitant jet recorded. The

cross sectional area is one way of measuring the EROA.

Problems with vena contracta as marker of severity

This method is simple and thought to be independent of haemodynam-

ics, driving pressure, and flow rate. However, low colour gain, poor

acoustic windows, or failure to assess multiple jets can underestimate

the vena contracta. A high colour gain, irregular shape of jet, or atrial

fibrillation can lead to overestimation.

Flow convergence (PISA—proximal isovelocity surface area) (see b p.126)

Pulmonary venous flow

Normally blood flows from the pulmonary veins throughout the cardiac

cycle. As mitral regurgitation becomes more severe left atrial pressure

increases more rapidly during systole and reduces the amount of blood

that can flow from the pulmonary vein (blunted systolic pulmonary vein

flow). With severe regurgitation atrial pressures are high and blood starts

to be forced back into the veins (reversed systolic pulmonary flow).

• Obtain an apical 4-chamber view with enough depth to see the back of

the left atrium.

• Try to identify the pulmonary vein orifices on the back of the left

atrium. With transthoracic echocardiography, often only the right

upper pulmonary vein (by the atrial septum) is seen and can be aligned.

• Place the PW sample volume 71cm into the ostium of the vein

(Fig. 3.9).

• A good spectral tracing confirms you are in the right place.

• Look at the systolic and diastolic components.

• If they are in opposite directions with the systolic component going

away from the probe report reversed systolic flow.

• If in the same direction, measure the height of the two waves and

comment if the systolic wave is blunted relative to diastolic or the

relation is normal (systolic slightly larger—systolic dominant).

122

CHAPTER 3 Transthoracic valves

Supportive measures

Mitral inflow

As regurgitation becomes more severe the amount of blood forced into

the left atrium during systole increases. This increased volume of blood

increases left atrial pressure. Therefore, blood leaves the atrium more

quickly at the start of diastole i.e. peak early diastolic velocity increases.

• In an apical 4-chamber view place the PW Doppler cursor at the mitral

valve tips.

• E wave >1.2m/s is indicative of severe mitral regurgitation (Fig. 3.10).

• However, a hyperdynamic circulation or even minor degrees of mitral

stenosis can also increase E wave amplitude. If the A wave is dominant,

severe mitral regurgitation is virtually ruled out.

Continuous wave Doppler intensity/shape

• In an apical 4-chamber view place the CW Doppler through the mitral

valve orifice and record a spectral trace (Fig. 3.11).

• Make a qualitative judgement about the density of the systolic regurgitant

waveform relative to the mitral inflow density. If they are the same this

suggests there is as much blood flow into the atrium during systole as

back into the ventricle during diastole and regurgitation is severe. (Peak

velocity allows calculation of regurgitant orifice area (b p.126).)

Regurgitant volume/regurgitant fraction

The principle behind the regurgitant volume is that the amount of blood

that flows through the mitral valve into the left ventricle during diastole

(assuming there is no aortic regurgitation to fill the ventricle as well)

should equal the amount of blood that leaves the left ventricle during sys-

tole. The amount of blood leaving through the aortic valve in systole can

be calculated and subtracted from the amount flowing across the mitral

valve in diastole. The difference is the volume flowing back through the

incompetent mitral valve. Regurgitant volume is not usually calculated as

accuracy depends on accurate measures of the outflow tract and mitral

valve area. The mitral ring is difficult to assess because it is not circular and

changes throughout the cardiac cycle. To measure:

• In apical 4-chamber view record PW at the mitral valve (it is controversial

whether the sample volume should be at annulus or valve tip level). Trace

the vti. Estimate mitral valve cross-sectional area (CSA). Use annulus

width and assume a circular orifice (alternatively measure the annulus in

two perpendicular planes and calculate area as an oval).

Mitral inflow volume = vti CSA mitral valve

• In apical 5-chamber view record PW in left ventricular outflow and

measure vti. Measure outflow tract diameter in parasternal long axis

and estimate CSA (assuming it is circular).

Left ventrication outflow = vti CSA left ventricular outflow

• Mitral regurgitant volume is:

Mitral inflow volume left ventricular outflow volume

• Regurgitant fraction is: (<20% mild, >50% severe regurgitation)

Mitral regurgitant volume mitral inflow volume

124

CHAPTER 3 Transthoracic valves

3D in assessment of mitral regurgitation?

3D colour flow imaging may be useful for:

Qualitative assessment of regurgitant jet

• 3D colour flow mapping of mitral regurgitation allows the mitral

regurgitation to be assessed in all planes, proving useful in the

analysis of eccentric mitral regurgitation or visualization of multiple

jets (Fig. 3.12).

Quantitative assessment of regurgitant jet

3D can also be used to measure the same parameters that have been

measured by 2D. There is no unique, additional 3D parameter but 3D

can be particularly useful to ensure accuracy of measures. For example:

• Estimation of the PISA value by the operator assumes that flow

acceleration is symmetrical towards the regurgitant orifice. This

geometric assumption is not always true and can be evaluated in 3D

as the entire flow convergence area can be displayed and viewed

from the left atrium. Thus 3D allows for a better judgement of the

likely accuracy of 2D PISA values. Theoretically, it would be possible

to measure the area in 3 dimensions to obtain a very accurate PISA.

• 3D echocardiography also allows the anatomic regurgitant orifice

area to be measured directly using planimetry of the regurgitant

orifice or regurgitant jet where it passes through the valve. This

has been shown to correlate well with the EROA calculated by the

proximal convergence method.

Remember that acquisition of 3D colour flow often requires more cycles

to be captured than for anatomical images. Therefore reconstruction

can be difficult as there may be problems with artefacts, especially with

atrial fibrillation. However, advancing technology is heading towards

clinically useful real-time 3D colour flow mapping.

126

CHAPTER 3 Transthoracic valves

PISA (proximal isovelocity surface area)

PISA or flow convergence zone is a measurement of how much blood trav-

els through a valve. It has been applied in several situations (e.g. aortic

regurgitation, mitral stenosis) but is validated for assessment of mitral

regurgitation. If regurgitation is mild, only blood near the valve moves

towards the atrium. With severe regurgitation blood further away in the

ventricle moves backwards. An impression of how far this flow convergence

zone extends into the ventricle is obtained by looking at the velocity of

blood flow in the ventricle with colour flow mapping. To quantify the

distance you use the principle that at a certain velocity the colour flow

will alias (change colour). The further away this change in colour, the more

blood is being funnelled back through the mitral valve, and the more se-

vere the regurgitation. In 3D the aliasing layer is a coloured hemisphere

sitting on the mitral valve. The PISA refers to the surface area of the hemi-

sphere (Fig. 3.11) and correlates to the regurgitant flow.

Assessment

• Get a good image of the mitral valve (usually the apical 4-chamber

view is best) and ensure you are in the plane of the regurgitant jet.

You

can use this velocity if the flow convergence is obvious but to optimize

the colour contrast at the boundary layer it is normal to shift the zero

of the baseline so that the aliasing velocity is 40cm/s.

• Acquire a loop of the cardiac cycle and scroll through to identify the

mid-systolic hemisphere shell. (Fig. 3.13).

• Measure the radius (r) from valve orifice to point of colour change.

If the colour flow is obscuring the valve orifice on your loop, place a

caliper at the aliasing zone then suppress the colour flow and position

the second cursor on the valve.

• Report severity based on the parameters listed in b ‘Grading

severity’, p. 126.

Grading severity

Radius (r):

A simple approach is just to record r with the aliasing velocity set at 40cm/s.

Severe mitral regurgitation is present if r >1cm and mild if <0.4cm.

Regurgitant flow:

and has been validated

against angiographic grades of regurgitation. Clinically it is normally used

with the continuous wave Doppler velocity to measure orifice area.

Effective regurgitant orifice area:

Regurgitant flow can be combined with the peak continuous wave velocity

(b p.122) to calculate effective regurgitant orifice area (EROA).

regurgitant flow

EROA

peak velocity on CW

0-20 mm2: mild; 20-40 mm2: moderate; >40 mm2: severe.

128

CHAPTER 3 Transthoracic valves

Mitral valve prolapse

Early studies suggested a high prevalence of up to 20% for mitral valve

prolapse but revised criteria for diagnosis have lead to more conservative

estimates of around 2%. The key to the change is the differentiation of an

anatomically normal valve that bows more than normal from a thickened

valve, classically with myxomatous degeneration, that truly prolapses. This

is important because it is only the latter patients who have clinical com-

plications. Prolapse can be seen with M-mode but 2D is usually preferred

to identify the condition. 3D echocardiography allows detailed anatomical

assessment of all mitral valve scallops, the geometry of the mitral valve

annulus, and the anatomy of the subvalvular apparatus. Studies have shown

that when image quality is adequate, 3D transthoracic echocardiography

has a similar accuracy for identifying segmental prolapse as transoesopha-

geal 2D echocardiography.

Assessment

• Study the valve in the parasternal long axis view.

• Comment on leaflet thickening or abnormal appearance.

• Report mitral valve prolapse if one or both leaflets entirely crosses

the plane of the mitral valve annulus back into the left atrium during

systole and the tip is >2mm into the left atrium. If the tip is within the

plane of the annulus and there is no more than trivial regurgitation

then this can be reported as bowing, without prolapse (Fig. 3.14).

• The leaflet position relative to the valve plane is determined precisely

by drawing a line between each side of the annulus.

• Comment on which leaflets (and scallops if possible) prolapse and

check if any part of the prolapsing leaflet is flail (see b p. 130).

• Report any associated changes in the subvalvular apparatus (papillary

muscle or chordae rupture).

• Report degree of regurgitation (remember anterior leaflet prolapse

will be related with posteriorly-directed regurgitation and vice versa).

3D in assessment of mitral prolapse?

3D echocardiography allows the mitral valve anatomy to be viewed from

multiple planes from different directions, thus increasing the operator’s

understanding of the mechanism of the mitral valve prolapse.

• Obtain a 3D view from the parasternal rather than apical windows as

this improves imaging with the probe closer to the valve.

• Rotate the image to obtain an en face or ‘surgeon’s view’ looking

from the left atrium.

• Report prolapsed position and extent.

• Use the reconstructed full volume dataset to demonstrate and

measure the maximal position of prolapse (Fig. 3.15).

• Use 3D colour flow to confirm the direction, number and extent of

eccentric jets.

130

CHAPTER 3 Transthoracic valves

Flail leaflets

Flail leaflets (Fig. 3.16) usually occur due to damage to the subvalvular appa-

ratus. This can be secondary to degeneration, destruction by endocarditis,

or ischaemia associated with myocardial infarction. The extent of the flail

can vary from just the leaflet tip (due to chordae failure) through to the

whole valve (usually papillary muscle rupture). The degree of flail associates

with the severity of the associated regurgitation. This can vary from mild to

severe and clinically from asymptomatic to haemodynamically unstable.

• Report a flail leaflet/leaflet scallop/leaflet tip if part of the leaflet points

back into the left atrium in systole rather than towards the ventricle.

• Comment on which leaflet is affected. If you can see, mention how

extensive and which scallop.

• There will be regurgitation so report severity.

• Assess both papillary muscles and the chordae to look for ruptures.

To look at the subvalvular apparatus use a combination of views—

parasternal long and short axis, all the apical views (2-chamber view

can be good to see both papillary muscles) and subcostal views.

• Report related findings according to suspected clinical aetiology,

e.g. regional wall motion abnormalities and left ventricle function in

myocardial infarction, vegetations in endocarditis.

Transthoracic assessment for mitral valve repair

When assessing the echocardiographic suitability for mitral valve repair,

note:

Leaflet motion and structure

• Record whether the leaflet motion appears normal, excessive due to

prolapse, or restricted.

• The anatomy of each leaflet and its integrity should be noted.

Normal leaflet thickness is <5mm.

Annulus size

• Accurate annulus size measurement should be performed and

documented.

Calcification

• The presence and degree of calcification should be accurately

documented at the annulus, leaflets, and subvalvar apparatus.

Mitral regurgitation severity and mechanism

• The MR jet direction, severity and mechanism should be reported.

If there is a question over the MR severity/mechanism or the quality of

transthoracic images obtained then TOE is indicated.

132

CHAPTER 3 Transthoracic valves

Aortic valve

Normal anatomy

The aortic valve has 3 cusps of similar size, which close to form a Y shape.

Each cusp tip has a small thickened nodule (nodule of Arantius). The cusp

edges usually overlap by 2-3mm and the lines where they meet are called

commissures. Closure of the cusps is referred to as coaption and opening

as excursion. Around each cusp are outpouchings of the aortic root called

the sinuses of Valsalva. The sinuses create a pool of blood above the valve

in diastole that improves blood flow down the coronaries and ensures a

tight seal. Cusps and associated sinuses are named according to the coro-

nary artery that originates from the sinus (right, left, and non). Above the

valves the bulging sinuses merge into the tubular ascending aorta at the

sinotubular junction. Below the valve is the left ventricular outflow tract made

up of the membranous interventricular septum, anterior mitral valve leaflet,

and anterior left ventricular wall.

Normal findings (Fig. 3.17)

2D views

• The minimal views are: parasternal long axis, parasternal short axis

(aortic valve level), and apical 5-chamber.

• Aortic valve velocities are also obtained from the right parasternal

view, which can be used for detailed assessment of aortic stenosis.

• Apical 3-chamber and subcostal views can also be used.

• Suprasternal view allows measurement of flow in the aorta for

assessment of aortic regurgitation.

2D findings

Aortic valve

• Parasternal long axis: 2 cusps are seen (usually right coronary by

septum and non-coronary by mitral valve). The leaflets open to lie

parallel to the aorta and close to form 2 curved lines.

• Parasternal short axis (aortic valve level): all 3 cusps are seen (left

cusp on the right, right cusp at the top, and non-coronary cusp on the

right). This is the classic Y-shape view. The left main coronary artery

may be seen and helps identify the left coronary cusp.

• Apical 5- and 3-chamber: the valve is aligned for Doppler measures

and 2 cusps are seen (usually non-coronary cusp next to atrium and

right coronary cusp next to septum).

Sinuses of Valsalva and sinotubular junction

• Parasternal long axis: the sinuses bulge to the right of the valve and the

sinotubular junction is the point where the ascending aorta starts.

• Parasternal short axis (aortic valve level): sinuses surround each cusp.

Left ventricular outflow tract

• Best seen in parasternal long axis. Formed by septum and anterior

mitral valve leaflet. Usually around 2cm wide and roughly circular.

134

CHAPTER 3 Transthoracic valves

Aortic stenosis

General

Aortic stenosis is common. Aortic valve thickening occurs in 25% of peo-

ple aged >65 and severe stenosis occurs in 3% aged >75. In the West, the

predominant cause is calcific degenerative disease. A bicuspid valve occurs

in 2% of the population. Rheumatic disease is now uncommon.

Assessment

The echocardiographic study is aimed at determining the appearance of

the valve, the grade of stenosis, the effect on the left ventricle, and the

presence of associated disease.

Appearance

Comment on:

• Degree and distribution of thickening. The term aortic sclerosis

describes valve leaflet thickening (>2mm) without significant stenosis

(Vmax < 2.5m/s).

• How many functional cusps (2 in a bicuspid valve, 3 in rheumatic or

calcific degenerative disease)? (Fig. 3.18)

• Is the closure line central (calcific degenerative or rheumatic disease)

or eccentric (bicuspid valve)?

• Motion: normal or reduced? Systolic bowing (bicuspid or rheumatic)?

• Commissural fusion (rheumatic disease).

• Associated rheumatic mitral stenosis suggests a rheumatic aetiology.

Grading severity

Grade stenosis from peak velocity across the valve, mean pressure gradient,

and effective orifice area (calculated from the continuity equation) (Table 3.3).

Sometimes further supportive measures can be used such as direct

planimetry of the aortic valve area using 2D or 3D.

Aortic peak velocity

• In apical 5-chamber view (or 3-chamber) align the continuous wave

Doppler, from the apex, through the aortic valve into the aorta. Spend

some time looking for the maximum velocity. Always repeat this

measurement with the stand alone CW probe from the apex.

• Record several beats and measure the peak velocity on the spectral

trace with the greatest velocity. This can be affected by the filling time

so ignore ectopic or post-ectopic beats and in atrial fibrillation average

2 or 3 beats. (Fig. 3.19).

• Repeat the measurement in at least one other approach

(e.g. suprasternal or right parasternal) and report the maximum

velocity found from all measures.

136

CHAPTER 3 Transthoracic valves

Peak pressure gradient

The peak gradient is usually automatically calculated by the machine from

the peak velocity. The relation between the two is very simple (the simpli-

fied Bernouli equation).

gradient =

× peak velocity

The equation is less accurate if the peak velocity is <3.0m/s and the long

form of the Bernoulli equation can be used:

Peak gradient =

× (V V )

where v2 = peak aortic velocity and v1 = peak left ventricular outflow

tract velocity.

Mean pressure gradient

To obtain the mean pressure gradient trace the continuous wave spectral

trace of flow through the aortic valve (Fig. 3.19) and the machine will

automatically calculate the vti (velocity time integral) and mean pressure

gradient (mean pressure across the valve during systole).

Effective orifice area/valve area

The continuity equation is based on the principle that the volume of blood

that flows through the left ventricle outflow tract during 1sec must equal

the blood through the aortic valve during 1sec.

• Obtain the continuous wave Doppler trace through the aortic valve

(Fig. 3.19) and record the peak velocity and vti(VALVE).

• In an apical view, record PW Doppler in the left ventricle outflow

tract (LVOT). Trace the waveform and record peak velocity and

vti(LVOT). (Fig. 3.20).

• In the parasternal long axis view zoom in on the LVOT and measure

the diameter. Record the maximum edge-to-edge diameter just below

the insertion of the aortic valve leaflets.

• Calculate the CSA of the LVOT:

Area LVOT =

×(LVOT diameter

)

• Put the figures into the rearranged continuity equation:

Valve area = Area LVOT × vti

vti

(LVOT

)

(VALVE)

The equation can be calculated with peak velocity substituted for vti.

138

CHAPTER 3 Transthoracic valves

3D in assessment of aortic stenosis?

Planimetry of the aortic valve area can be undertaken on 2D images

although this can be inaccurate. As with 3D transthoracic imaging of

mitral stenosis, a combination of live 3D and full volume acquisitions

has been employed to estimate aortic valve area by planimetry using

3D. Recent papers suggest assessment of aortic stenosis by planimetry

of transthoracic 3D images has good agreement with standard 2D tran-

soesophageal imaging. However, planimetry is limited due to limited

spatial resolution and to be accurate requires excellent image quality.

Valvular calcification related to the aortic stenosis can be problematic

as it causes drop-out artefacts distal to the probe. Sometimes, apical

windows (Fig. 3.21) may provide a more effective window as drop-out

from the calcification extends into the aorta rather than across the

posterior part of the valve. However, resolution may be reduced

because of the increased distance between probe and valve. If you want

to use 3D to support suspicions of severity gathered by 2D imaging then

do the following:

• Obtain a 3D volume of the aortic valve, ideally from a parasternal

window as this is closest to the valve.

• Use post-processing analysis software to align a 2D plane accurately

through the tips of the aortic valve.

• Trace around the inner edge of the valve and calcifications and

report planimetered valve area.

Effect of other diseases on diagnosing and grading stenosis

• Moderate or severe aortic regurgitation will increase transaortic

flow and may lead to overestimation of the grade of stenosis if using

gradient alone. The continuity equation remains valid and should be

used.

• Left ventricular dysfunction can be associated with lower transaortic

and LVOT velocities and therefore underestimation of gradient. The

continuity equation remains valid and should be used.

• A subaortic membrane or septal hypertrophy may occasionally be

mistaken for valvular stenosis. Use PW Doppler in different positions

in the LVOT to identify whether the blood starts to accelerate

below or at the level of the valve.

• Examine the aorta for dilatation of the ascending aorta (commonly

associated with bicuspid aortic valve, but also with calcific

degenerative disease). If a bicuspid valve is suspected, use the

suprasternal window to look for associated aortic coarctation.

• Pulmonary hypertension is common in severe aortic stenosis and

is associated with a high operative risk. Estimate pulmonary artery

pressure and assess the right ventricle.

140

CHAPTER 3 Transthoracic valves

Effect on the left ventricle

Left ventricular hypertrophy or concentric remodelling (relative wall thick-

ness >0.45 without hypertrophy (see b p.218) are usual in compensated

severe aortic stenosis. The left ventricle can also dilate if there is high wall

stress as a result of severe pressure load, excessive fibrosis, or another

cause of left ventricle dysfunction (e.g. myocardial infarction).

• During assessment of aortic stenosis also report a full evaluation of the

left ventricle (for function, see b p.226 and for hypertrophy, see b

p.218).

A common dilemma in the relation between the left ventricle and aortic

stenosis is whether any left ventricular dysfunction is secondary to the

stenosis or another pathology (e.g. ischaemia). Also, an apparently small

gradient or a decline in gradient may be secondary to impaired left ventri-

cle function. The continuity equation remains accurate and should be used

to assess valve area.

• If the mean gradient is <30mmHg (suggesting mild to moderate

stenosis) but the valve area calculated by the continuity equation

is <1.0cm2 (suggesting severe stenosis) then a dobutamine stress

echocardiogram can be considered to differentiate:

• End-stage severe aortic stenosis.

• Moderate aortic stenosis associated with left ventricle dysfunction

from another cause (e.g. myocardial infarction or myocarditis).

Dobutamine stress echocardiography

Give low-dose dobutamine intravenously (5 then 10, if necessary 20 mi-

crograms/kg/min in 5-min stages). Aim for a 10% increase in heart rate or

20% increase in LVOT or aortic valve vti (Fig. 3.22). If the patient also has

coronary artery disease, ischaemia may occur at very low levels of stress

in the presence of aortic stenosis.Therefore carefully monitor wall motion

and left ventricle size to look for evidence of ischaemia during the study

(see Chapter 10).

There are two things to look for during the study. The first is to deter-

mine whether severe aortic stenosis is present or not. The second is to

determine whether the impaired left ventricle is able to increase output

(ventricular reserve is present). This is important because the risk of

mortality following aortic valve replacement for severe aortic stenosis is

approximately 5% if contractile reserve is present and 35% if absent.

• Severe aortic stenosis is defined by:

• Mean gradient >30 mmHg at any time during dobutamine stress.

• Valve area <1.2 cm2 throughout the infusion.

• Ventricular reserve is present if there is:

• A rise in LVOT vti by >20% during the study.

142

CHAPTER 3 Transthoracic valves

Aortic regurgitation

General

Aortic regurgitation (AR) is usually seen easily with colour flow Doppler

imaging over the aortic valve, which has 95% sensitivity and 100% spe-

cificity. Traces of central regurgitation are seen more frequently with

increasing age (<1% below 40 years; 10-20% at 60 years; and in the major-

ity >80 years), but are not clinically significant.

Causes of AR are listed in Box 3.1; changes in either the aortic root or the

valve itself can be the underlying pathology.

Assessment

Use colour flow mapping to identify and describe any AR (Fig. 3.23). The

study should then look for probable aetiology, grade severity, and check

for associated problems.

Appearance

• Map the regurgitation with colour flow. Use colour flow mapping to

identify and describe any AR. The study should then look for probable

aetiology, grade severity, and check for associated problems.

• Visualize the regurgitation with colour flow.

• Look at the jet in all views and establish the shape and pattern of

the regurgitation.

• Comment on whether it is central, eccentric, along a commissure,

or even through a perforation (often easiest to see in parasternal

short axis views).

• Use a systematic approach to establish cause based on the clinical

situation:

• Aortic root: in the parasternal long axis, measure aortic root

dimension, look for a dissection flap. In parasternal short axis look

at the aortic root for evidence of thickening or abscess.

• Aortic valve: parasternal long axis—abnormal valve motion/

prolapse, vegetations, calcification/rheumatic changes. Parasternal

short axis—number of cusps.

• Look at the rest of heart: Evidence of congenital abnormalities that

may relate to AR, e.g. ventricular septal defect?

• For prosthetic valve regurgitation, comment on whether the

regurgitation is through the valve (valvular) or around the side

(paravalvular), and document any degree of valve motion relative to

the annulus (‘rocking’).

AORTIC REGURGITATION

143

Box 3.1 Causes of aortic regurgitation

Aortic valve

• Degeneration: calcific

• Infectious: endocarditis, post rheumatic fever

• Congenital:

• Bicuspid valve

• Associated with other congenital abnormalities.

Aortic root dilatation

• Hypertension

• Dissection/aneurysm

• Trauma

• Congenital (e.g. Marfan’s, Ehlers-Danlos)

• Osteogenesis imperfecta

• Inflammatory:

• Rheumatoid arthritis

• Systemic lupus erythematosus

• Syphilis, Reiter’s syndrome

• Giant cell arteritis, ankylosing spondylitis.

Aortic regurgitation

Fig. 3.23 Examples of colour flow Doppler of aortic regurgitation. Top: apical

5-chamber view demonstrating severe regurgitation with a long, broad jet. Bottom:

parasternal long axis view showing mild regurgitation. See W Video 3.14.

144

CHAPTER 3 Transthoracic valves

Grading severity

Assess the severity of AR using jet width, vena contracta and descending

aortic flow (Table 3.4). Once you have an impression of the severity use

pressure half-time and LV function to further your assessment.

Vena contracta

• The vena contracta is the narrowest part of the colour Doppler jet,

where flow convergence occurs. Best seen in parasternal long axis

view.

• Measure the vena contracta width perpendicular to the jet direction

with calipers and report the absolute measurement. Severe

regurgitation is associated with width >0.6cm (Fig. 3.24).

• The same measurement can be done in cross-section in the

parasternal short axis view, though it is difficult to be sure you are at

the correct level (at the narrowest point).

Jet width as proportion of outflow tract

• Measure the vena contracta (jet width).

• Suppress the colour and measure the width of the LVOT at the same

point.

• Report the jet width as a percentage of LVOT. Severe regurgitation is

suggested by a jet that is >65% of outflow tract.

• Jet size assessed in parasternal short axis can also be used (although

technically more difficult and does not supply more information).

Report area relative to left ventricle outflow tract area in the same

view.

Problems using jet width to assess AR

• Eccentric jets tend to ‘flatten out’ along the outflow tract wall and

are no longer circular in cross-section, so will have different widths

depending on the orientation of the image plane.

• Changes in gain and colour scale will affect jet width, so control

settings should be kept constant (50-60cm/s), especially for F/U.

Descending aorta flow

• In the suprasternal view, obtain a view of the aortic arch and

descending aorta (Fig. 3.25).

• Place the PW Doppler cursor in the centre of the descending aorta

and look at the spectral trace.

• Flow down the descending aorta is normally away from the probe

(below the line) for virtually all of the cardiac cycle.

• Examine diastolic flow—a small amount of flow reversal (above

the line) may be seen at the start of diastole. However, in severe

regurgitation, all flow during diastole is reversed (back towards the

heart) as a large volume of blood flows back into the ventricle. If this is

seen, report holodiastolic aortic flow reversal (Fig. 3.25).

AORTIC REGURGITATION

145

Table 3.4 Parameters to determine severity of aortic regurgitation

Mild

Severe

Specific signs of severity

Vena contracta

<0.3cm

>0.6cm

Jet (Nyquist

central, <25% of LVOT central, >65% of LVOT

50-60cm/s)

Descending aorta

No or brief early-

Holodiastolic flow reversal

diastolic flow reversal

Supportive signs of severity

Pressure half time

>500ms

<200ms

Left ventricle (only for

Normal LV size

Moderate or greater LV

chronic lesions)

enlargement (no other cause)

Report as moderate if signs of regurgitation are greater than mild but there are no features

of severe regurgitation.

LVOT

Vena contracta

Jet width as

proportion of LVOT

Fig. 3.24 Parasternal long axis with vena contracta and left ventricular outflow tract

diameter marked. See W Video 3.15.

146

CHAPTER 3 Transthoracic valves

Supportive signs

Pressure half time

Obtaining the spectral Doppler trace

• In the apical 5-chamber (or 3-chamber) view, align the CW Doppler

through the AR jet (identified with colour flow mapping). Try and

ensure the Doppler passes through the regurgitant orifice of the valve

and is in line with the jet direction (for eccentric jets the view may

need to be adjusted).

• On the spectral trace, the regurgitant jet will be seen as a broad trace

with a flat, sloped top, above the baseline that coincides with diastole

on the ECG (Fig. 3.26).

• Measure the slope of the flat part of the curve. The deceleration slope

(the slope of the curve) and pressure half-time (time for pressure to fall

by a half) are usually calculated automatically. The two measures are

generally correlated.

Parameters to assess

• Density of the waveform compared to the systolic waveform. Similar

density suggests severe regurgitation.

• Peak diastolic velocity (usually 4-6m/s).

• The pressure half-time: <200ms indicates the pressure between the

aorta and left ventricle equalizes very quickly in diastole (usually due to

a large regurgitant volume) and suggests severe regurgitation. See also

b p.150.

• The deceleration slope: >400cm/s2 indicates severe AR (the larger the

number, the steeper the slope).

Left ventricle

• Serial studies of changes in left ventricular size are useful in monitoring

progression of AR and help decide the timing for intervention.

• Assessment can be based on standard measures of LV size (b p.196).

• A LV end-diastolic dimension of >7cm and/or LV end-systolic

dimension of >4.5 cm are markers of severe LV dilation ± dysfunction

2° to chronic AR.

148

CHAPTER 3 Transthoracic valves

Other possible measures of AR severity

Length of the jet

A rough estimation of the severity of AR can be made on the length of the

jet: if the jet reaches the end of the anterior mitral valve leaflet (moder-

ate) or extends into the body of the LV (severe); Fig. 3.27. Originally this

was performed using PW Doppler to identify the jet, but this has been

extrapolated to colour flow jets which are highly dependent on control

settings due to the low velocities at the boundary layers.

Jet area

Judging the severity of AR by the size (area) of the regurgitant jet is

inaccurate—it is susceptible to loading conditions, angles of the jet and

image plane, and colour flow settings, and should not be relied upon. In

addition, eccentric jets may be long and thin as they track along structures

and the severity is easily underestimated.

Colour M-mode

If the M-mode cursor is placed below the valve in a parasternal long axis

view with colour flow (Fig. 3.27), the position of the regurgitation within

the outflow tract and timing during diastole can be studied (e.g. late dias-

tole due to aortic leaflet prolapse or mild regurgitation in early diastole).

Measurements of jet width and left ventricular outflow tract can also theo-

retically be done with the same tracing.

3D assessment of aortic regurgitation?

3D echocardiography modes (full volume datasets, live 3D or colour

Doppler imaging) can be used to aid quantification of the severity of aor-

tic regurgitation. The same parameters as developed in 2D are used but

the 3D datasets allow better alignment for assessment. This is because

the pyramidal datasets can be cropped in any plane so even eccentric

jets can have accurate plane alignment. Studies have demonstrated that

the measurement of vena contracta width and vena contracta area show

good correlation with the angiographic grading of the aortic regurgita-

tion severity.

• To measure vena contracta use the parasternal window to obtain a

3D dataset.

• To measure vena contracta area use postprocessing to create an en

face 2D view of the regurgitation jet as it passes through the aortic

valve and LVOT. Then scan up and down the jet to identify the

narrowest past and trace around the vena contracta. Report the area

relative to the outflow tract area at that level.

• For the vena contracta width postprocess the 3D dataset as for

area but this time create an imaging plane that lies parallel to the

regurgitant jet. Then scan through the jet to identify the plane that

cuts through the narrowest point. Measure the jet width and report

the value relative to the outflow tract width.

150

CHAPTER 3 Transthoracic valves

Quantifying regurgitant volume

This can be calculated because blood flow across the aortic valve in sys-

tole should be the same as the blood flow into the LV during diastole.

The diastolic component comprises blood flow across the mitral valve

plus any AR. Both flow across the aortic valve in systole and mitral inflow

can be calculated and the aortic regurgitant flow will be the difference

between the two:

gurgitant volume

mitral valve inflow

The principle is the same as that used for determining regurgitant volume

in mitral regurgitation, and the same measures (mitral valve inflow and LV

outflow tract flow) are used (see b p.122 for how to measure these).

Interestingly, the stroke volume should be the same at any valve in the heart

if it is competent and there is no shunt, so if measurements are difficult at

the mitral valve, the pulmonary or tricuspid could be used. Theoretically,

the proximal isovelocity surface area (PISA) method (b p.126) can be used

at any regurgitant valve, although it is usually only practical and validated

for the mitral valve.

However, the calculation has several potential areas of inaccuracy:

• Measuring LVOT flow and mitral inflow involves significant

assumptions and calculations, and these may be inaccurate. Calculating

a third measurement from these 2 derived parameters carries a high

risk of further inaccuracy.

Significant mitral regurgitation reduces systole aortic flow and distorts the

measurement.

Acute or chronic regurgitation?

• In acute severe AR, the LV is usually of normal dimension and

thickness, with vigorous function. In chronic severe AR there has

been time for dilatation and possibly eccentric hypertrophy.

• Acute severe AR is usually poorly tolerated by patients, due to the

lack of time for LV compensation, and they are very symptomatic,

often in heart failure.

• Cause: dissection and endocarditis are likely causes of acute AR.

• Pressure half-time is particularly useful as a marker of severity in

acute regurgitation. With chronic regurgitation left ventricular

function and aortic compliance change to accommodate larger

regurgitant volumes. This slows down the equalization in pressure

and leads to a longer pressure half-time.

152

CHAPTER 3 Transthoracic valves

Bicuspid and quadricuspid valves

The aortic valve can occur with fewer or more than 3 cusps. Bicuspid

valves are seen in 2% of the population and quadricuspid valves in 0.04% of

the population (Fig. 3.28). 5 cusps have also been reported although this

may often be secondary to endocarditis. Sometimes valves have 3 cusps

but are functionally bicuspid because of fusion of 2 cusps along a commis-

sure. Bicuspid valves are often associated with aortic stenosis and multiple

cusps with aortic regurgitation.

It is very easy to make a tricuspid valve appear bicuspid in a parasternal

short axis view if the plane is slightly off axis. If you suspect a bicuspid valve

make sure this is consistent in several views. Clues to a valve being truly

bicuspid include:

• Leaflets of unequal size. True congenital bicuspid valves occur because

of failure of separation of the right and non-coronary cusp or failure of

separation of the right and left coronary cusps.

• An atypical orientation of the commissure in the parasternal short axis.

This will either lie roughly horizontal (between 10 and 4 o’clock) or

roughly vertical.

• Abnormal valve motion (best seen in a parasternal long axis view). The

valve typically domes with the valve opening off centre.

When assessing a bicuspid valve report the suspected cause, e.g. true

congenital or due to valve fusion, degree of calcification (they are more

prone to degeneration), associated functional problems (regurgitation and

stenosis), associated congenital problems (they are linked with coarcta-

tion of the aorta), and associated changes to the aorta (e.g. dilatation or

dissection).

Lambl’s excresences

These are thin strands attached to the aortic cusps several millimetres

long. They are also seen on the mitral valve. They are not clinically signifi-

cant although their relevance will depend on the clinical situation as it is

important not to miss endocarditis vegetations.

154

CHAPTER 3 Transthoracic valves

Tricuspid valve

Normal anatomy

The tricuspid valve has 3 cusps of unequal size: anterior (largest) extends

from infundibulum anteriorly to the inferolateral wall posteriorly. The pos-

terior leaflet arises along the posterior margin of the annulus from the

septum to the inferolateral wall and the septal (smallest) leaflet extends

from the interventricular septum to the posterior ventricular border

(Fig. 3.29). Their anatomy is very variable. The free margins of the cusps

are attached to chordae tendinae which are, in turn, attached in groups to

three papillary muscles (anterior, posterior, and septal) that project from

the septum and right ventricular free wall. Chordae from each papillary

muscle attach to all leaflets. The valve has an annulus and valve ring with a

normal area of 5-8cm2. The valve allows free flow of blood from the right

atrium during diastole but closes as systole increases the intraventricular

pressure. Abnormalities of the tricuspid valve must not be overlooked,

especially in mitral valve disease.

Normal findings

2D views

• The best views are: parasternal short-axis (aortic valve level), right

ventricular inflow, apical 4-chamber, and subcostal views.

2D findings

• Parasternal short axis (aortic valve level): the tricuspid valve lies to

the right of the aorta. The anterior leaflet is seen on the left and

septal is closest to the atrial septum. In all views the tricuspid leaflets

demonstrate wide diastolic opening and a normal coaptation in systole.

• Right ventricular inflow: this gives a very good view of the posterior

(on the left) and anterior (on the right) leaflets as well as the right

atrium, right ventricle and, sometimes, the inferior vena cava, coronary

sinus and Eustachian valve.

• Apical 4-chamber: the anterior and septal leaflets are seen (septal

nearest the septum). In this view the tricuspid annulus (normal adult

28 ± 5mm) should lie closer to the apex (up to 1cm) than the mitral

annulus. This plane also provides a good view of the right heart.

• Subcostal 4-chamber: this view allows good access to images of the

right atrium, atrial septum and inferior vena cava. The tricuspid valve

(anterior and septal leaflets) is usually clearly seen similar to the apical

4-chamber view.

3D views and findings

• 3D datasets are best obtained from the apical position. However, it is

possible to use a modified position within the parasternal window that

lies close to the tricuspid valve, or sometimes a subcostal window.

• The tricuspid valve and apparatus has a complex geometrical shape

and 3D views can be used for a more detailed quantitative assessment

of the anatomy prior to surgical intervention.

156

CHAPTER 3 Transthoracic valves

Tricuspid regurgitation

General

Tricuspid regurgitation is common. Because the leaflets are irregular a

small amount of central, physiological regurgitation is seen in up to 70%

of normal individuals. Physiological regurgitation is associated with normal

valvular anatomy and no dilatation of the RV. Pathological regurgitation

is usually secondary to right ventricular and tricuspid annular dilatation.

Primary causes of tricuspid regurgitation are due to changes to the valve

or subvalvular apparatus (Box 3.2).

Tricuspid regurgitation is usually seen in patients with multiple valve

lesions, including aortic and mitral.

Assessment

‘Physiological’ regurgitation should be commented upon (<1cm adjacent

to valve closure). Transthoracic echocardiography should aim to establish

the aetiology of pathological tricuspid regurgitation and provide a quanti-

tative estimate of severity. The assessment must also include evaluation of

the right-sided chambers (Table 3.5).

Appearance

• Anatomy: assess for prolapsing (usually septal and anterior), flail,

or billowing valve. An apical 3D full-volume set enables detailed

assessment of tricuspid valve apparatus from multiple views and

commissural fusion/leaflet coaptation can be assessed using the

‘en face’ view.

• Look at the regurgitant jet with colour flow Doppler in several views

and comment on the direction and size of the jet.

• Report abnormal valve appearance (restricted motion and thickening

of carcinoid, vegetations of endocarditis or valve rupture).

• Report tricuspid valve annulus size.

• Report right heart size and function (b p.264) and assess right

ventricular systolic pressure (b p.162).

Pacemakers and tricuspid regurgitation

Tricuspid regurgitation is more common with a pacemaker lead (both

temporary and permanent) because it disrupts leaflet coaption. Tricuspid

valve velocity however will not be affected as this is determined by right

ventricular systolic pressure.

TRICUSPID REGURGITATION

157

Box 3.2 Causes of tricuspid regurgitation

Valve and apparatus

• Infection

• Endocarditis

• Rheumatic heart disease

• Congenital: Ebstein’s anomoly

• Metabolic: carcinoid

• Connective tissue disease

• Subvalvular

• Chordal rupture

• Papillary muscle dysfunction

• Infiltration

• Malignancy

• Non-penetrating trauma.

Right heart

• Pulmonary hypertension

• Right heart failure with lung pathology

• Ischaemic heart disease

• Pulmonary valve disease

• Cardiomyopathy

• Volume overload

• Pacing lead

Table 3.5 Parameters to assess severity of tricuspid regurgitation

Mild

Severe

Qualitative

Valve structure

Normal

Abnormal

Jet (Nyquist 50-60cm/s)

<5cm2

>10cm2

CW trace

Soft & parabolic Dense & triangular

Semi-quantitative

Vena contracta

>0.7cm

PISA r (Nyquist 40cm/s)

<0.5cm

>0.9cm

Tricuspid inflow

Normal

E wave dominant >1m/s

Hepatic vein flow

Normal

Systolic reversal

Quantitative

EROA

Not defined

40mm2

R vol

Not defined

>45mL

RV/RA/IVC

Normal size

Usually dilated

Report as moderate if signs of regurgitation are greater than mild but there are few

features of severe regurgitation.

158

CHAPTER 3 Transthoracic valves

Grading severity

• The methods to grade severity are borrowed directly from those used

for mitral regurgitation. Assessment of tricuspid regurgitation tends to

be more subjective with less clinical need for accuracy. Colour flow

imaging should be used to diagnose TR. Quantitative assessment is

performed using vena contracta, flow convergence (PISA), continuous

wave density, and contour. There are also changes in hepatic vein flow

which are equivalent to changes in pulmonary vein flow seen in mitral

regurgitation (see Table 3.5). It is essential to use multiple views to

assess severity.

Vena contracta

• In the apical 4-chamber view place colour flow over the tricuspid valve

and obtain a plane that demonstrates the regurgitant orifice.

• Zoom in on the valve and measure the vena contracta (narrowest

diameter of the colour flow jet as it passes through the valve)—>7mm

suggests severe regurgitation, see Fig. 3.30.

Continuous wave Doppler waveform

• In the apical 4-chamber, parasternal short axis or right ventricular

inflow views drop the continuous wave through the tricuspid valve

aligned with the regurgitant jet.

• Report the signal intensity relative to the antegrade flow and comment

on the waveform (parabolic or triangular). Triangular and dense

suggests severe regurgitation, see Fig. 3.31.

• Use TR jet to determine RV or pulmonary artery systolic pressure

(b p.162)

Jet area

• In the apical 4-chamber view obtain an image that includes the entire

right atrium and the main plane of the regurgitant jet.

• Record a loop and scroll through to a frame with the largest jet.

Trace around the jet and report the area. >10cm2 suggests severe

regurgitation.

Right ventricular inflow

• Flow of blood into the right ventricle can be used as a guide to

severity (equivalent to measurement of E wave velocity in mitral

regurgitation). Peak E velocity at the tricuspid valve of ≥1m/s

suggests severe tricuspid regurgitation.

Hepatic vein flow

• In a subcostal view place the PW Doppler cursor in a hepatic vein that

aligns with the probe and record a spectral tracing of flow. Normally

flow through both systole and diastole is towards the right atrium. In

severe tricuspid regurgitation the rise in right atrial pressure leads to

flow away from the right heart during systole. Report systolic flow

reversal if seen.

160

CHAPTER 3 Transthoracic valves

3D for assessment of tricuspid regurgitation?

3D echocardiography can be used to help quantify tricuspid regurgitation

severity and also the mechanism, in particular the annulus size (Fig. 3.33).

Colour flow mapping

• As with 3D the assessment of mitral regurgitation, full volume

colour Doppler imaging permits the regurgitant jet to be rotated and

cropped to ensure that the vena contracta is being measured in a

plane that is parallel to the jet and also at the narrowest point during

maximal flow (Fig. 3.32).

• 3D echocardiography allows the valve to be assessed from the ‘en

face’ view to help identify prolapsing valve segments accurately.

Tricuspid annulus

• Real-time 3D transthoracic echocardiography is routinely available

and allows simultaneous assessment of the morphology, movement

of the three leaflets and attachment to the tricuspid annulus.

• It has been shown that 3D echocardiography allows visualization

and measurement of the entire oval-shaped annulus in patients

with dilated or normal sized annuluss, something which was

underestimated by 2D echocardiography.

Mild and severe tricuspid regurgitation

Fig. 3.32 Colour flow mapping of tricuspid regurgitation in apical 4-chamber views

with examples of mild (top) and severe (bottom) regurgitation. See W Video 3.21.

162

CHAPTER 3 Transthoracic valves

Right heart haemodynamics

The most widely reported haemodynamic measure in echocardiography is

right ventricular systolic pressure. This is partly because it has a broad clini-

cal relevance and partly because it is easy to measure as it uses tricuspid

regurgitation—found in 70% of individuals.

Measurement is based on velocity of regurgitation across the tricuspid valve.

This is used to calculate pressure across the valve—the higher the pressure

in the right ventricle relative to the right atrium, the higher the velocity

of regurgitant blood. To calculate right ventricular systolic pressure right

atrial pressure must be added to this pressure. Fortunately, there are clinical

(jugular venous pressure [JVP]) and echocardiographic methods (inferior

vena cava [IVC] and right atrial size) to estimate right atrial pressure.

Right atrial pressure

• JVP can be used but requires accurate clinical assessment with the

patient lying at 45°. The measure lacks accuracy if very low or very high

and is directly affected by moderate to severe tricuspid regurgitation.

• A floating constant of 5, 10, or 15 mmHg can be used based on the

pattern of changes in right atrial size, inferior vena cava, and tricuspid

regurgitation severity (Table 3.6).

• Assess right atrial size from an apical four chamber view (b p.284).

Report as normal, dilated, or very dilated. Measure IVC diameter

from a subcostal view (<1.7 cm is normal, except in athletes when

diameter can be 2-3cm) and check for respiratory variation (ask the

patient to sniff). IVC should reduce in size by around 50% (Fig. 3.34).

Tricuspid regurgitation severity is assessed routinely (b p.158).

• If accurate assessment of right atrial pressure is not possible then

a constant of 10mmHg (or 14mmHg) can be used but this will

systematically overestimate right systolic ventricular pressures (RSVP) at

low levels and underestimate it at high levels.

• Recently, an alternative approach has been suggested based on IVC

diameter and response to sniff. If IVC <2.1cm and collapses >50% then

RA pressure is 3mmHg. If IVC >2.1cm and collapses <50% then RA

pressure is 15mmHg. Otherwise assume pressure is 8mmHg.

Tricuspid velocity and right ventricular systolic pressure

• In apical four chamber, parasternal short axis or right ventricular inflow

view, align continuous wave through the tricuspid valve regurgitation.

• Record a spectral trace and measure the peak velocity (Fig. 3.35).

Based on the simplified Bernoulli equation:

Pressure gradient

u peak velocity²

• Report right ventricular systolic pressure as the tricuspid pressure

gradient plus the estimate of right atrial pressure.

Pulmonary artery systolic pressure

• By subtracting the pressure gradient across the pulmonary valve

(b p.174) from right ventricular systolic pressure you can calculate

pulmonary artery systolic pressure. Because the gradient is usually small

and right atrial pressure is estimated, right ventricular systolic pressure

is often reported as pulmonary artery systolic pressure.

RIGHT HEART HAEMODYNAMICS

163

Table 3.6 Parameters to help identify fluid status

Suggests

Normal range

Suggests volume

hypovolaemia

overload

IVC diameter

<1cm and collapsing 1-2.5cm, collapsing

>2.5cm, no response

and response

25-75%

to respiration

LVIDd/BSA (cm/m2) <2.4 women

2.4-3.2

>3.2

<2.2 men

2.2-3.1

>3.1

LVEDAI (short axis) <5.5

5.5-10

>10

End point septal

<0.5m

>0.5cm

separation

LVESD

Papillary apposition 2.0-4.0cm

RV internal dimensions

See below

RVIDd >LVIDd

Interventricular

No flattening

Diastolic flattening

septum

Right atrium

<20cm2

>30cm2

NO RESPIRATORY

VARIATION

AT REST

ON INSPIRATION

NORMAL

ABNORMAL

Fig. 3.34 The 2D images demonstrate normal respiratory variation of the inferior

vena cava and the M-mode trace lack of variation.

Fig. 3.35 The tricuspid valve has been focused on from the apical 4-chamber view

to obtain a continuous wave Doppler trace across the tricuspid valve to measure

peak velocity and derive a pressure gradient.

164

CHAPTER 3 Transthoracic valves

Tricuspid stenosis

General

Tricuspid stenosis is rare. The commonest cause is rheumatic heart disease

with coexistent mitral stenosis. Other causes include: carcinoid (Fig. 3.36),

lupus valvulitis, pacemaker or valvular endocarditis, right atrial tumour,

and obstruction of right ventricle inflow tract (large atrial thrombus or

large vegetations). It is usually associated with tricuspid regurgitation.

Appearance

Comment on:

• Leaflet thickening or calcification.

• Leaflet motion: classically restricted with diastolic doming of 1 or more

leaflets (especially the anterior leaflet).

• Right atrial enlargement.

• Dilated IVC.

• 3D echocardiography provides anatomical detail of leaflets and orifice

area.

Grading severity

• Determine severity on the transvalvular gradient (Table 3.7):

• Use CW Doppler aligned across the tricuspid valve in an apical

4-chamber view (averaged throughout the respiratory cycle).

• Measure peak velocity (Fig. 3.37) and calculate peak gradient using

the Bernoulli equation.

• Severe tricuspid stenosis is associated with a valve area of <1cm2 or

a peak gradient of >7mmHg (mean >5mmHg) and an inflow time-

velocity integral >60cm.

• Pressure half time can not be used to measure valve area as the

appropriate constant for the tricuspid valve has not been determined.

• Severity can also be assessed from valve area. This can be calculated

using the continuity equation. A PW Doppler vti can be taken at

the level of the valve annulus and the CSA of the tricuspid annulus

calculated based on the annulus diameter and the assumption that the

orifice is circular. These measurements can then be combined with the

continuous wave vti across the valve.

Tricuspid valve area = (Annulus PW vti area of annulus)/valve CW vti

3D for assessment of tricuspid stenosis?

• In mitral stenosis it is possible to accurately planimeter the valve

orifice area in the short axis view with 2D imaging. Due to the

complex geometry of the tricuspid valve it is not possible to

accurately assess the valve orifice area with 2D short axis views.

• 3D echocardiography allows the tricuspid valve to be rotated

and cropped in any plane and to appreciate the morphology from

short axis views and to also see the valve en face and delineate the

individual leaflets. Both of these 3D tools can be used to planimeter

the orifice.

166

CHAPTER 3 Transthoracic valves

Tricuspid valve surgery

Tricuspid valve surgery—replacement or annuloplasty—is considered in

severe tricuspid regurgitation with haemodynamic consequences or when

associated with mitral valve disease.

Carcinoid syndrome

Characterized by the release of 5-hydroxytryptamine from a metastasizing

tumour resulting in thickened and shortened tricuspid leaflets with severe

tricuspid regurgitation. The pulmonary valve may also be involved and the

right atrium and right ventricle are frequently dilated.

Infective endocarditis

Right-sided endocarditis is uncommon except in intravenous drug users,

patients with indwelling catheters, or those with ventricular septal defects.

Vegetations usually occur on the tricuspid valve (Fig. 3.38) in intravenous

drug use, but many have associated left-sided lesions.

Ebstein anomaly

A congenital anomaly of the tricuspid valve with apical displacement of 1

or more leaflets. This diagnosis should be considered when the distance

between the mitral and tricuspid valve planes is >1cm. There is enlarge-

ment of the right atrium and tricuspid regurgitation.

3D transthoracic echocardiography provides detailed anatomical and func-

tional images prior to surgical intervention.

168

CHAPTER 3 Transthoracic valves

Pulmonary valve

Normal anatomy

The pulmonary valve consists of 3 leaflets: anterior, left, and right. It

develops alongside the aortic valve and then the right heart and pulmonary

artery twists around the left heart and aorta. The valve lies at the junction

of the right ventricular outflow tract and the pulmonary trunk. It is thinner

than the aortic valve as a result of the lower right heart pressures.

Normal findings

Views

• There are limited views of the pulmonary valve (Fig. 3.39). The best

views are the parasternal short axis (aortic valve level) and the right

ventricular outflow. Subcostal short-axis views (at the aortic valve

level) can also be used but are similar to the parasternal short axis

view.

Findings

• Parasternal short axis (aortic valve level): this provides a view of the

tricuspid valve, right ventricle, and pulmonary valve wrapped around

the aortic valve. The pulmonary valve lies on the right and this view

can be used to align Doppler through the right ventricle outflow,

pulmonary valve, and pulmonary artery.

• Right ventricular outflow: in some people this provides excellent views

of the pulmonary valve, pulmonary artery, and bifurcation. This view

can also be used for alignment of Doppler.

170

CHAPTER 3 Transthoracic valves

Pulmonary regurgitation

General

Colour flow mapping of the pulmonary valve identifies small regur-

gitant jets in most people (Fig. 3.40). These can often be quite eccentric.

Pathological causes of regurgitation are similar to those for tricuspid

regurgitation (Table 3.5, Box 3.2).

Primary valve problems include: rheumatic heart disease, infective endo-

carditis, carcinoid, iatrogenic

(post-valvuloplasty), congenital

(following

surgery for tetralogy of Fallot, leaflet absence). Secondary causes are

due to dilatation of the pulmonary artery (e.g. pulmonary hypertension,

Marfan’s).

Appearance

• Examine for anatomic abnormalities to identify mechanism of

regurgitation including anomalies of cusp number, structure or

movement. Comment on any visible valve pathology (e.g. thickening,

vegetation).

• Map the regurgitation with colour flow in the parasternal short

axis and right ventricular outflow views. Comment on size, site of

regurgitation, and direction.

• Pulmonary regurgitation is commonly at one edge of a commissure

and can appear to lie next to the aorta. This should not be confused

with an aorta-pulmonary communication which would have flow

throughout the cardiac cycle instead of just during diastole.

172

CHAPTER 3 Transthoracic valves

Grading severity

• Criteria for assessment are borrowed from aortic regurgitation but

assessment is more qualitative (Table 3.8).

• Grade severity as mild, moderate or severe based on:

• Jet length and width relative to outflow tract: Jet diameter is

measured at pulmonary valve leaflets level during early diastole:

jet diameter >0.98cm indicates significant regurgitation. Jet width

>65% of right ventricular outflow tract indicates severe pulmonary

regurgitation.

• Pulmonary regurgitation index (PR Index) is the ratio between

pulmonary regurgitation time and total diastole. An index <0.77

suggests severe PR. The lower the value, the more severe the

regurgitation.

• Vena contracta width lacks validation. 3D vena contracta provides

more quantitative assessment of PR. EROA values mild <20mm2,

moderate 21-115 mm2, and severe >115mm2 have been proposed.1

• Continuous wave regurgitation intensity and shape. Increased

intensity and slope of the Doppler signal (deceleration time)

suggests severe (Fig. 3.41).

•

(Abnormal pulmonary artery anatomy suggests more severe

regurgitation.)

• Flow across pulmonary valve relative to systemic circulation and

evidence of right ventricle dilatation.

• Holodiastolic flow reversal in the main pulmonary artery

(equivalent to aortic flow reversal) suggests severe regurgitation.

• Comment on changes to the right heart—with severe PR, patients

often develop RV dilatation from volume overload and tricuspid

annulus dilatation and tricuspid regurgitation.

Pulmonary artery diastolic pressure

• The velocity of the regurgitant jet can be used to quantify the pressure

gradient (using the Bernoulli equation) between the pulmonary artery

and right ventricle during diastole.

• Add right ventricular diastolic pressure (assumed to be right atrial

pressure, see Table 3.6) to the pulmonary valve pressure gradient to

calculate pulmonary artery end diastolic pressure.

• To calculate mean pulmonary artery end pressure use pulmonary artery

systolic pressure (b p.162) in the equation:

diatolic pressure+ systolic pressure

PULMONARY REGURGITATION

173

Table 3.8 Parameters to assess pulmonary regurgitation

Mild

Severe

Pulmonary valve anatomy

Normal

Abnormal

Jet size on colour flow

<10mm long

Large with wide origin

CW density and shape

Soft and slow

Dense and steep

PR Index

<0.77

Jet width of RVOT

>65%

Pulmonary artery flow

Increased

Greatly increased

compared to systemic

Right ventricle size

Normal

Dilated

If features suggest more than mild regurgitation but no features of severe grade as moderate.

Slope of Doppler is

guide to severity

Fig. 3.41 Doppler features to assess pulmonary regurgitation.

Reference

1 Pothineni KR et al. Live/real time three dimensional transthoracic echocardiographic

assessment of pulmonary regurgitation. Echocardiography 2008; 26(8):911–17.

174

CHAPTER 3 Transthoracic valves

Pulmonary stenosis

General

Pulmonary stenosis is usually valvular and congenital

(e.g. related to

rubella, Noonan’s, or tetralogy of Fallot). The valve usually has fusion of

several cusps to form a funnel. Pulmonary stenosis can also occur due to

stenosis of the main pulmonary artery (e.g. following rubella, post-surgical

banding of the pulmonary artery) or subvalvular problems (e.g. congenital

in association with valvular stenosis, tetralogy of Fallot, and transposition

of the great arteries).

Rheumatic pulmonary stenosis is rare. Carcinoid disease is the commonest

cause of acquired pulmonary stenosis. Functional pulmonary stenosis may

arise from RV outflow tract compression by tumours.

Appearance

• Comment on the valve:

• Number of leaflets.

• Thickened, dysplastic, calcified leaflets.

• Motion: doming of valve leaflets in systole and restricted motion.

• Measure size of pulmonary annulus.

• Comment on associated structures:

• Right ventricular outflow tract and evidence of narrowing, e.g.

infundibular/subvalvar stenosis.

• Post-stenotic dilatation of the pulmonary artery.

• Right ventricular hypertrophy.

• Functional tricuspid regurgitation secondary to pressure overload.

Grading severity

Grade severity based on the peak gradient. This can be supported by

calculating the valve effective orifice area (Table 3.9).

• In the parasternal short axis (aortic valve level) or right ventricular

outflow view measure the velocity across the pulmonary valve with

CW Doppler aligned through the right ventricular outflow tract,

pulmonary valve and common pulmonary artery.

• Report velocity and gradient across the valve (calculated with the

simplified Bernoulli equation). Mean gradient and pulmonary valve vti

can be obtained by tracing the spectral waveform (Fig. 3.42).

• Measure right ventricular systolic pressure.

• The continuity equation can be used to measure effective orifice area

of the pulmonary valve. In the parasternal short axis view record a

right ventricular outflow tract (RVOT) PW Doppler peak velocity or

vti (velocity(RVOT)). Measure the outflow tract diameter at this point

and calculate a CSA assuming it is circular (cross sectional area(RVOT)).

Then use the continuity equation including these measures and the

peak velocity or vti from CW across the valve (velocity _{(pulmonary valve)}).

Pulmonary valve CSA equals:

velocity

×cross-sectional area

⎤

velocity

⎣

(RVOT

)

(RVOT

)

⎦

(pulmo

nary value

)

176

CHAPTER 3 Transthoracic valves

Mechanical prosthetic valves (Fig. 3.43)

All mechanical valves consist of a mobile component (occluder), the

restraining system

(to restrict occluder motion), and the sewing ring

(attaches prosthesis to vessel). Blood flow is restricted through these and

normal pressure gradients are therefore higher across mechanical, com-

pared to native, valves. Valve components are metallic or plastic coated,

with a carbon layer. These cause shadows and reverberations so scanning

from different positions is required to assess the valve. In particular, mitral

prosthesis regurgitation is masked on transthoracic images and if valve

dysfunction is suspected transoesophageal imaging maybe required.

Ball and cage (Starr Edwards)

The ball and cage valve consists of a sewing ring attached to a cage made

of 3 or 4 struts. The blood flows on all sides around a Silastic ball occluder,

which moves within the cage. Blood flow is directed laterally within the

valve and converges downstream (Fig. 3.44, upper image).

Assessment

Use all standard imaging planes adjusted where necessary with slight rota-

tion or tilting to minimize shadows.

Normal appearances

Whether valve is open or closed there will be significant shadows from

the sewing ring and reverberation from the ball. Structures and flows

behind the valve are masked. Physiologic regurgitation is a trivial central jet.

Tilting disc (e.g. Medtronic-Hall, Omniscience)

A single circular disc suspended within a frame, with an off-centre hinge

point. Opening therefore creates 2 orifices, 1 large (major) and 1 small

(minor).

Assessment

Use standard imaging planes with slight rotation or tilting as necessary.

Images are usually best when through the central hinge point or perpen-

dicular to the closed disc. For mitral prostheses use apical windows for

assessment. For aortic prostheses use apical windows for Doppler and

parasternal to differentiate valvular from perivalvular regurgitation.

Normal appearances

There are shadows from the sewing ring and reverberations from the disc

throughout the cardiac cycle.

• Valve closed: structures and flow behind the valve are masked.

Physiologic regurgitation is 2 small jets between disc and ring. Some

may have a jet associated with the central strut and some a very long

central jet.

• Valve open: disc opens to 55-75°. The strut can be seen in a central

position underneath the sewing ring. 2 colour jets can be displayed.

CW Doppler velocities are similar through minor and major orifice.

MECHANICAL PROSTHETIC VALVES

177

BALL AND CAGE

BILEAFLET

TILTING DISC

STENTED

BIOPROSTHESIS

BLOOD FLOW

CLOSED

OPEN

THROUGH VALVE

Fig. 3.43 Diagram of mechanical prosthesis design and blood flow.

When to use transoesophageal echocardiography?

Transthoracic echocardiography usually provides good alignment with

the transprosthestic flow. Therefore detection of prosthesis stenosis is

not a problem. However, transthoracic assessment of regurgitation is

limited by shadowing and distance to the transducer. Haemodynamic

assessment or an aortic valve prothesis is usually better with a transtho-

racic study. Indications for transoesophageal imaging are:

• Transthoracic imaging is inconclusive or non-diagnostic.

• Transthoracic findings not in agreement with clinical findings.

• Suspected problems of mitral mechanical valve prosthesis.

• Suspected prosthetic valve endocarditis.

• Suspected prosthetic valve thrombosis.

• Intraoperative use (to guide repair, assess success, complications).

178

CHAPTER 3 Transthoracic valves

Bileaflet (e.g. Carbomedics, St. Jude)

These consist of 2 leaflets, separately hinged in the centre of the prosthe-

sis. 3 orifices are created in the open position: 2 large lateral orifices and

1 small central orifice (Fig. 3.44, lower image). If used in the aortic position

a supra-annular placement is often possible and may be used in double

valve replacement in order to achieve greater separation of the valves.

Assessment

As for single tilting disc, use standard imaging planes, mainly apical for

mitral prostheses and both apical and parasternal for aortic valves. Before

making diagnosis of impaired motion of one or both discs, ensure trans-

ducer has been rotated thoroughly to obtain a position in which the cur-

sor (ultrasound beam) is aligned perpendicularly to the central line of the

disc coaptation.

Normal appearances

There will be shadows from the sewing ring and reverberation from discs

throughout the cardiac cycle.

• Valve closed: discs close at about 25° and mask structures and flow

behind the valve. Physiologic regurgitation is up to 4 jets originating at

pivot points near the edge of the valve.

• Valve open: discs open to 55-75° and 2 separate discs are often seen.

There is more flow acceleration through the narrow central orifice.

Therefore CW measures through the centre may overestimate the

overall pressure gradient, especially for small aortic prosthetic valves.

Use mean rather than peak gradient.

Physiologic regurgitation

Physiologic regurgitation is normal with tilting disc and bileaflet proth-

eses. There are 2 components: (1) an initial backward flow during valve

closure (2) holosystolic flow designed to ‘wash’ the valves and reduce

risk of valve thrombosis. These are referred to as ‘wash’ or ‘closing’

jets.

Differentiation of closing and physiologic jets from pathological

regurgitation?

Physiologic jets:

• Flow is contained within the sewing ring.

• Colour flow pattern is usually thin and laminar.

• Jet length usually less <2-3cm.

Pathologic jets:

• Any perivalvular jets (outside the sewing ring).

• Different from the expected signature of the physiologic pattern for

the valve.

180

CHAPTER 3 Transthoracic valves

Bioprosthetic valves

Bioprosthetic valves are made from porcine aortic valve or bovine pericar-

dium. The leaflets are stiffer than native valve leaflets. Bioprostheses may

be stented or stentless. Stents or struts support the cusps and protrude

downstream (into the aorta with aortic bioprostheses or left ventricle

with mitral bioprostheses). Struts and the ring are metallic so cause shad-

owing (although less than mechanical prostheses). Some models can be

implanted in a supravalvular position. Although their flow profile is similar

to native valves, there is still an increased pressure gradient across the

prosthetic valves, particularly stented bioprostheses.

Stented bioprosthesis (Fig. 3.45)

Assessment

Use standard scan planes. Image prostheses through apical windows with

the beam perpendicular to the closed leaflets. Rotate transducer whilst

using colour flow mapping to assess perivalvular regurgitation.

Normal appearance

There will be shadows from the sewing ring and stents protruding down-

stream throughout the cardiac cycle. In the apical view usually 2 struts are

displayed and, in the short axis, the ring and 3 struts are visible. If the aortic

root is dilated there may be free space between sewing ring and root.

• Valve closed: leaflets appear thin like a native valve. Physiologic

regurgitation may be present as small central jet (usually early

postoperatively).

• Valve open: valve opens widely with leaflets parallel to the stent

(2-4mm distance).

Stentless bioprosthesis

Assessment

Use standard scan planes. Usually no shadowing.

Normal appearance

Usually very similar to native aortic valve. Leaflets may appear thickened

and junction between valve and annulus may be thickened due to sutures.

Pulmonary valve homografts may have supravalvular thickening and ste-

nosis. Ideally, no regurgitant jet but sometimes minor distortion during

implantation or due to mismatch of prosthesis causes mild central regurgi-

tation. Jet may be eccentric if due to distortion.

Homografts and autografts

May be used in endocarditis or as an autograft in young patients in aortic

valve disease (Ross procedure: native pulmonary valve is used for aortic

valve replacement and a bioprosthesis is implanted as pulmonary valve).

Scan planes and appearances are as for stentless bioprosthesis.

182

CHAPTER 3 Transthoracic valves

Prosthetic valve abnormalities

Vegetation, thrombus, pannus

Extended masses on a prosthesis. Pannus is excessive endothelial prolifer-

ation causing obstruction and/or failure in complete valve closure. Pannus

is sometimes difficult to distinguish from thrombus. Both may be present.

No specific texture differentiates masses so to differentiate use:

• Appearance: thrombi usually larger, protrude from the sewing ring and

less echocardiographically dense.

• Clinical information: suboptimal anticoagulation makes thrombus more

likely, bacteraemia makes vegetation more likely.

• Associated abnormalities: vegetations may be associated with

paravalvular abscesses, leaks.

Bioprosthetic valve degeneration

Observed in most prostheses after several years. Infrequent in first 3 years.

Leaflet calcification results in irregular thickening (usually >3mm in thick-

ness). Rigid leaflets have decreased cusp motion, cause stenoses and may

rupture resulting in prolapse (or flail cusp) and valvular regurgitation.

Prosthetic valve dehiscence—‘rocking’ valve (Fig. 3.46)

Exaggerated mobility of valve ring indicates dehiscence. Assess with 2D.

Usually associated with severe paravalvular regurgitation. Valve dehis-

cence is usually preceded by paravalvular leaks.

Valve prolapse In bioprostheses, prolapse of leaflet tissue is possible

and is seen in standard views. Usually leaflets are degenerated (irregular

thickening and calcification) and valvular regurgitation will be present.

Structural damage For example, broken occluder or restraining

system, will be combined with intravalvular regurgitation.

Sutures Seen as immobile, dense structures within the ring. Can

be difficult to differentiate from focal fibrosis. They will be mobile if

dehisced.

Strands Mobile, filamentous strands on normal and abnormal valves

(rarely seen adjacent to native valve). Thought to be fibrin strands

(they can disappear after thrombolysis of thrombosed prostheses).

Poor reproducibility in imaging these structures as visualization is highly

dependent on machine settings.

Pseudo-microbubbles (Fig. 3.47) Look like single contrast microbubbles.

Probably due to micro-cavitation. Found with normal valves but more

often if valve dysfunction. Appear as dots, moving away from prosthesis,

visible only shortly after valve closure (unless valvular or paravalvular leak).

In contrast, spontaneous echo contrast is seen only in areas of low blood

velocity (therefore not at orifices or leakages of prosthetic valves) and is

smoke-like in appearance with swirling patterns.

184

CHAPTER 3 Transthoracic valves

Prosthestic valve stenosis

Prosthetic valve stenosis suggests an acceleration of blood through the

prosthetic valve because of some pathology. Pressure gradients may go up

with thrombus/pannus and, rarely, vegetations or degeneration.

Assessment

General

If stenosis is suspected, initial assessment should be to look for pathology

that might explain stenosis (thrombus, vegetation, valve dysfunction) and

check the level of any obstruction (outflow tract, valve level). Then gather

supportive information about severity of any stenosis.

Grading severity

Pressure gradient and velocity (Fig. 3.48)

Techniques are as for native valves (CW Doppler) but mechanical pros-

theses can have 2 or 3 different-sized orifices so application of Bernoulli

equation is not straightforward and calculations can vary depending on

Doppler alignment. With cage-and-ball prostheses it is almost impossible

to get optimal Doppler alignment. In clinical practice, calculation of effec-

tive orifice area is useful.

Orifice area—aortic valve prostheses

Use same technique as for native valve (CW, PW, and LVOT diameter).

Reporting orifice area also avoids problems with variation in cardiac out-

put. For St. Jude bileaflet aortic prosthesis a Doppler velocity index has

been validated:

vti across LVOT/vti across aortic valve <0.23 suggests severe stenosis

Orifice area—mitral valve prostheses

Use techniques as for native valves. The pressure half-time tends to under-

estimate effective orifice area but can be used. Width of the forward flow

may be an alternative, if measured in 2 orthogonal planes.

What is abnormal for prosthetic valves?

Normal mechanical and stented bioprostheses have a pressure gradient

equivalent to mild or moderate stenosis. Normal ranges vary between

manufacturers and valves so refer to published information to give clini-

cal advice. Pressure gradients also vary with haemodynamics, such as

cardiac output, so there is considerable interpatient variability. General

principles about what might need investigation are best based on calcu-

lated orifice area:

• Aortic prostheses may be stenotic if calculated valve area is <1cm2

or there has been a >30% change from last follow-up.

• Mitral prostheses may be stenotic if pressure half-time >200ms

and peak diastolic velocity >2.5m/s (if only mild regurgitation).

• Tricuspid prostheses may be stenotic if peak diastolic velocity

>2.5ms (if only mild regurgitation).

Peak prosthetic aortic jet velocity > 3 m/s

DVI

≥ 0.30

0.25-0.29

< 0.25

Jet contour

AT (ms)

>100

<100

>100

<100

Consider PrAV stenosis with

Suggests PrAV

Consider improper

Normal PrAV

• Sub-valve narrowing

stenosis ^†

LVOT velocity**

• Underestimated gradient

• Improper LVOT velocity*

EOA

index

High flow

PPM

Fig 3.48 Algorithm for evaluation of elevated peak prosthetic aortic jet velocity incorporating DVI, jet contour, and acceleration time (AT). *Pulse wave (PW)

Doppler sample too close to the valve (particularly when jet velocity by continuous wave (CW) Doppler is

4m/s). ** PW Doppler sample too far (apical) from

Stenosis further substantiated by estimated orifice area (ERO) derivation compared with reference values if

valve type and size are known. Fluoroscopy and trans esophageal echocardi-ography (TEE) are helpful for further assessment, particularly in bileaf-let valves. Aortic

valve replacement (AVR). Doppler velocity index (DVI) is the ratio of the proximal velocity in the left ventricle out flow tract to that of flow velocity proximal to

the stenosis. Adapted from Figure 10, Recommendations for Evaluation of Prosthetic Valves With Echocardiography and Doppler Ultrasound. American Society of

Echocardiography 2009, 22(0):975-1014.

186

CHAPTER 3 Transthoracic valves

Prosthetic valve regurgitation

• Transvalvular regurgitation describes regurgitation within the sewing

ring. This can be caused by leaflet prolapse (bioprostheses),

incomplete disc closure due to clot, pannus (mechanical prostheses)

or structural damage (broken retainment system, dislodged disc).

• Paravalvular regurgitation has its origin outside the sewing ring. This

can occur immediately after surgery (usually trivial and resolves after

protamine or with endothelialization during first few postoperative

weeks), be due to dehiscence of the sewing ring, or secondary to

endocarditis.

Assessment

Decide if regurgitation is transvalvular or paravalvular (Fig. 3.48).

When jet is easily displayed it is often paravalvular, as physiologic and

transvalvular regurgitation is shadowed by valve.

Use multiple views and look at jet position with colour flow (use system-

atic approach similar to identification of mitral leaflet scallop prolapse).

Short axis views of rings are very useful to position jets. 3D echocardi-

ography may give further information. If paravalvular, report extent and

localization with figure or reference to ‘clock face’ in parasternal short axis

view (for mitral valve, area adjacent to aortic valve is 12 o’clock).

Transoesophageal echocardiography provides a comprehensive assess-

ment of severity and cause. It should always be performed if transthoracic

screening suggests there may be clinically significant regurgitation.

Grading severity

Pathological regurgitant jets are usually eccentric and often multiple.

Shadowing from sewing ring, struts or disc limit field of view. Therefore,

colour flow area, PISA and vena contracta are not reliable. Assessment

of severity is often qualitative, in which case indirect supportive measures

should also be provided and transoesophageal echocardiography advised.

Supportive measures

• Increase in cavity diameters compared to previous studies.

• If no prosthetic stenosis, an increase in forward flow velocity (due

to volume overload). For mitral prostheses moderate to severe

regurgitation is suggested by a peak velocity >1.9m/s and mean

gradient >5mmHg. If no aortic stenosis and only mild regurgitation

then a ratio of vti mitral prothesis/vti aortic valve >2.5 suggests

moderate to severe regurgitation.

• Pulmonary venous flow for mitral regurgitation (systolic flow reversal).

If left ventricle function is impaired a blunted pulmonary vein flow

pattern is ‘normal’ after mitral valve replacement.

• Aortic flow pattern for aortic regurgitation (diastolic flow reversal).

Other techniques

With transvalvular regurgitation (both mitral and aortic) one option is to

measure the proportional area of the sewing ring occupied by the jet in a

short axis view: <10% is mild, 10-25% is moderate, and >25% is severe.

188

CHAPTER 3 Transthoracic valves

Endocarditis

Diagnosis of endocarditis is based on clinical factors

(positive blood

cultures with appropriate organisms, predisposing factors, new valve

dysfunction, peripheral stigmata) supported by echocardiographic abnor-

malities (Duke’s criteria are widely used). A normal echocardiogram never

excludes endocarditis and, if clinical suspicion is high, transoesophageal

echocardiography should always be performed. If normal, repeat imaging

can be considered to monitor for developing pathology.

Assessment

For diagnosis use a full systematic examination with focus on valves (main

site). Bear in mind clinical situation: right-sided valves if intravenous infec-

tion (drugs, lines), known abnormal valves (prosthetic or degenerative),

previous endocarditis (old vegetations). For monitoring use full examina-

tion and make sure you comment on change from previous findings.

For all studies report on: vegetations (location, number, size), abscess

(particularly valve rings), fistulae (e.g. aorta to right heart), valve dysfunc-

tion (including severity, dehiscence, rupture), pericardial effusion.

Vegetation (Fig. 3.49)

Key features to help diagnose: (1) attachment to upstream-side valve;

(2) irregular shape; (3) oscillating motion distinct from valve; (3) related

valve dysfunction. Comment on number of vegetations, attachments, size

(measure in at least 2 directions and provide overall assessment—small,

moderate, large).

Abscess (Fig. 3.50)

Abscesses can be perivalvular or valvular. Appearances initially are often

of a thickening and ‘spongy’ appearance to valve ring (particularly aor-

tic root) or valve leaflet. An echo-free, fluid-filled centre may develop.

Abscesses may open into adjacent cardiac chambers (technically the space

is then no longer an abscess).

For each abscess comment on location with reference to position around

valve (e.g. annulus right coronary cusp). Measure size in different planes

and judge as small, moderate or large. Comment on functional effects of

abscess (e.g. outflow tract or valve distortion).

Fistula

Fistulae usually develop following an abscess and describe an abnormal

connection between 2 cardiac chambers. Use colour flow mapping to

track fistulae and identify jets in cardiac chambers. If aligned, use Doppler

to quantify flow direction and size.

Comment on physical size (length and width) and which chambers are

connected. Give an estimate of haemodynamic significance (e.g. size of

shunt left-to-right heart, change in ventricle size and function, degree of

regurgitation if fistula across valve).

Severity of valvular lesion (see individual valve sections)

Pericardial effusion (see b p.298)

191

Chapter 4

Transthoracic anatomy

and pathology: chambers

and vessels

Left ventricle

192

Left atrial size

280

Left ventricular

Left atrial function

282

assessment 194

Left and right atria: normal

Left ventricular size

196

ranges 283

Left ventricular size: 2D

Right atrium 284

normal ranges 208

Right atrial size

284

Left ventricular thickness and

Interatrial septum

286

mass 210

Atrial septal defects

288

Left ventricular thickness and

Patent foramen ovale 290

mass: normal ranges 216

Atrial septal aneurysm

290

Left ventricular

Ventricular septum 292

hypertrophy 218

Ventricular septal defects

294

Hypertrophic

Pericardium 296

cardiomyopathy 220

Pericardial effusion

298

Left ventricular non-

Cardiac tamponade 300

compaction 222

Constrictive pericarditis

302

Restrictive

Congenital pericardial

cardiomyopathy 224

disease

306

Dilated cardiomyopathy 224

Pericardial tumours

306

Myocarditis 224

Acute pericarditis

306

Left ventricular function

226

Pericardiocentesis

306

Global systolic function

228

Aorta 308

Regional systolic function

234

Aortic size

310

Left ventricular strain

238

Aortic dilatation

314

Diastolic function

246

Marfan syndrome 316

HFNEF 252

Aortic dissection

318

Left ventricular

Aortic coarctation

320

synchrony 254

Sinus of Valsalva

Optimization 260

aneurysm 322

Right ventricle

262

Aortic atherosclerosis

324

Right ventricular size

264

Cardiac tumours 326

Right ventricular wall

Congenital heart disease 330

thickness

270

Congenital defects 336

Right ventricular function

272

Surgical correction of

Right ventricular

congenital heart

overload 276

disease

340

Left atrium 278

192

CHAPTER 4 Transthoracic chambers and vessels

Left ventricle

Normal anatomy

The left ventricle is a cavity with muscular walls that contains the papillary

muscles and their chordal attachments. The anatomic characteristics of

the chamber size and thickness can vary significantly with pathology, and

many cardiac and systemic processes are associated with cardiac dilatation

or hypertrophy.

Normal findings

2D views

The left ventricle is seen in virtually all windows. The minimal views are

parasternal long and short axis and the apical 4-, 2-, and 3-chamber views

(Fig. 4.1).

2D findings

• Parasternal long axis: the basal and mid segments of the septum

and posterior wall (in some publications it is also referred to as the

inferolateral wall) are visible. This view is used for linear measures of

wall thickness and cavity dimensions. The left ventricular outflow tract

can also be assessed.

• Parasternal short axis: by angling the probe back and forth, the whole

of the left ventricle can be scanned in cross-section. The key ventricle

views are mid-ventricle (mid-papillary) and apical. The mid-ventricle

level is used for linear and area measures of walls and cavity. Regional

wall motion abnormalities can also be assessed in (in clockwise order)

septum, anterior, lateral, and inferior walls.

• Apical 4-chamber: provides best views of apex, septum (on left) and

lateral (on right) walls for regional assessment. Suitable for tracing

ventricle area and left ventricle length.

• Apical 2-chamber: focuses on inferior (on left) and anterior walls (on

right).

• Apical 3-chamber: the parasternal long axis view but from the apex.

Looks at posterior (inferolateral) wall and septum.

• Subcostal provides an alternative view of the left ventricle but is not

essential.

3D views and findings

• 3D acquisitions of the left ventricle can be obtained from either the

parasternal or apical window.

• 3D full volume acquisition mode is preferably used to ensure that the

entire left ventricle is imaged.

• Following acquisition, the 3D image can be rotated and cut through

any plane to examine any region of interest.

• Good 2D endocardial definition is important when deciding on

suitability for 3D LV assessment.

• See Chapter 2.

194

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular assessment

General

Accurate left ventricular assessment (diameters, volumes, wall thickness,

mass, and function) is critical in clinical practice. Measurements can be

altered by virtually all cardiovascular pathologies. The most common indi-

cation for echocardiography is evaluation of left ventricular function, with

ejection fraction being the most sought parameter. Assessments are fre-

quently visually estimated but there is significant interobserver variability

and dependence on interpreter skill. Quantitative measures are recom-

mended to ensure diagnostic accuracy.

Assessment

• Start with an overview of the ventricle in all views (parasternal and

apical) and gather an impression of appearance, size, and function.

• Comment on obvious structural changes:

• Ventricular shape, aneurysms, wall thinning, wall hypertrophy, wall

character (‘speckling’ etc.).

• Report quantitative measures of size (b p.196) and a general

summary: normal, mild, moderate, or severe dilatation; normal, mild,

moderate, or severe hypertrophy. If hypertrophy, give an idea of the

pattern based on appearance and relative wall thickness, i.e. eccentric,

concentric, asymmetric (septal, apical) (b p.218).

•

2D and M-mode quantification of left ventricular size and mass has

been well validated but both have advantages and disadvantages.

• M-mode measures in parasternal views are widely used. They

are very dependent on M-mode alignment and take no account

of left ventricle shape or regional wall motion abnormalities.

The alignment problem is reduced with 2D guided or direct 2D

measures.

• In general, left ventricle shape changes are best accounted for by

using the volumetric biplane Simpson’s method for volumes and the

truncated ellipsoid method for left ventricle mass. These methods

should therefore be used to provide accurate assessment of left

ventricle volume and mass respectively.

• Reference ranges are dependent on gender and body habitus.

Ideally, height and weight should be recorded and body surface

area used to correct left ventricular dimensions.

• Using the measures of left ventricular size, report a quantitative

assessment of systolic function (e.g. ejection fraction) and summarize

as normal systolic function or mild, moderate, or severe systolic

dysfunction (b p.226).

• From apical and parasternal views look at changes in regional wall

motion (normal, hypokinesis, akinesis, dyskinesis, aneurysmal). Report

abnormalities (b p.234).

• When relevant, assess and report left ventricular diastolic function from

changes in mitral valve inflow and tissue Doppler imaging (b p.246).

• Finally, ensure you have reported fully pathologies that might relate to

the changes you have identified in the left ventricle (e.g. valve disease).

196

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular size

Because it is difficult to quantify a 3D structure using 2D imaging, the

techniques that developed with 2D echocardiography rely on measuring

the ventricle in standard places. The measures are then reported directly

(linear methods) or used in mathematical equations to model an assumed

shape for the ventricle (volumetric measures). In principle, the more meas-

ures of the left ventricle in the more planes the more accurate the as-

sessment. Conversely, the fewer measures the more assumptions have

to be made and the more likely that regional pathology is overlooked.

Sometimes—such as in a normal heart—simple linear measures are ade-

quate. However, if there is pathology accuracy is required. More recently,

collection of 3D datasets has enabled much more accurate chamber size

quantification.

Linear measures

M-mode

This is based on change in size in a single plane at the mid ventricle level

in a parasternal view (Fig. 4.2). Recent guidelines suggest this should be a

parasternal short axis view.

• Optimize a parasternal long axis view with the septum and posterior

wall lying parallel (or a parasternal short axis mid-ventricle view).

• Drop the M-mode cursor through opposing walls so that it intersects

both at right angles. In the long axis view the cursor should lie at the

level of the mitral valve tips (some guidelines suggest chordal level).

• Look at the M-mode trace and identify the 2 walls. Measure from

edge-to-edge where the walls are closest together (peak systole) and

furthest apart (end diastole). Report the left ventricle systolic and end-

diastolic diameters.

• The M-mode trace from a parasternal long axis view can also be used

to measure septal and posterior wall thickness at end diastole.

2D-imaging

This follows the same principle as M-mode but relies on clear 2D images.

• Record a loop of an optimized parasternal long axis or short axis (mid

ventricle) view. Identify the end-diastolic frame (largest ventricle).

• Measure from endocardial border to border at right angles to each

wall (Fig. 4.3). In the long axis view the line should pass through the

mitral valve tips. Report the left ventricular end-diastolic diameter.

• Scroll through the loop to identify the end-systolic frame (smallest

ventricle) and using the same technique measure the left ventricular

end-systolic diameter.

2D vs. 3D volume measurements

• Volumes obtained from 3D measurements are significantly larger than

the volumes measured with 2D techniques, contrast enhanced 3D

volumes are larger than corresponding volumes in native 3D echo.

• 3D LV ejection fraction are lower than in 2D (lower limit 49%).

• For longitudinal studies, the same imaging software and postprocessing

units should ideally be used in order to maintain consistency.

198

CHAPTER 4 Transthoracic chambers and vessels

2D volumetric measures

Simpson’s method

Simpson’s method (Fig. 4.4) is based on the principle of slicing the left

ventricle from apex down to mitral valve annulus into a series of discs. The

volume of each disc is then calculated (using the diameter and thickness of

each slice). All the disc volumes are added together to provide the total

left ventricular volume. If done in a single plane (based on apical 4-cham-

ber view) it is assumed the left ventricle is circular at each level. Accuracy

is improved by using diameters in 2 perpendicular planes (biplane—apical

4- and 2-chamber) so that the disc surface area is more precisely defined.

Although this can be done ‘by hand’ by measuring the diameter at multiple

levels, in reality, you trace the outline of the ventricle and the machine or

off-line software automatically calculates the volume.

• In the apical 4-chamber view obtain a clear image of the left ventricular

cavity with a clear endocardial border.

• Record a loop and scroll through to find the end-diastolic image

(usually just before the aortic valve opens or on the R-wave of the

ECG). This image should have the largest left ventricular volume.

• Trace around the endocardial border going from one side of the mitral

valve annulus to the other and joining the 2 ends with a straight line.

Record the left ventricular end diastolic volume.

• Measure the length of the left ventricle from apex to middle of mitral

valve. Depending on the machine, identification of the apex may be

automatic after tracing the border. Record left ventricular long axis.

• Scroll through the loop again and find the smallest left ventricular

volume at end-systole (usually just before the mitral valve opens or

on the T-wave of the ECG). Trace around the endocardial border, as

before, and record left ventricular end systolic volume.

• The method described will provide single plane measures of left

ventricular volumes. For biplane measures repeat the process for

diastolic and systolic images using an optimized apical 2-chamber view.

Normal ranges depend on technique, sex and body size

Systematic differences between techniques mean ‘normal’ ranges vary.

For instance, direct 2D measures tend to produce slightly smaller meas-

ures than M-mode. Also, normal ranges depend on the sex and size

of the person. Always report the method you used and demographic

data.

200

CHAPTER 4 Transthoracic chambers and vessels

Area length equation (Fig. 4.5)

This method can be used if apical definition is poor and it is difficult to

trace the border. It is based on an equation that models a ‘bullet-shaped’

ventricle (and therefore does not take account of regional abnormalities).

For the equation you need the length of the ventricle and the cross-

sectional area at the mid papillary level.

• Obtain a clear parasternal short axis (mid ventricle level) view with

good endocardial border definition and record a loop.

• Trace around the endocardial border in the end diastolic frame to

obtain the end-diastolic cross sectional area.

• In an apical 4-chamber view record the distance from the middle of

the mitral valve annulus to the left ventricle apex at end-diastole and

record the end diastolic left ventricle long axis lengths.

• Ventricular volume at end-diastole is then:

cross-sectional area in parasternal short axis ventricle length

• Ventricular volume at end-systole can be measured in exactly the same

way but using parasternal and apical images frozen at end-systole.

Avoid foreshortening—ensure a clear endocardial border

• Accurate left ventricular volume measurements require an

unforeshortened ventricle. Foreshortening leads to underestimation

of volume and changes ventricle shape. Foreshortening can usually

be avoided by moving more lateral ± 1 intercostal space further

down. 3 pointers to be confident you have identified the true apex:

• Apex is fixed and does not move towards the base in systole.

• Apical myocardium is thinner than the rest of the ventricle.

• The view is the one with the longest ventricle (if apical view).

• If the endocardial border is not clear, volumes will be overestimated.

Clear definition is particularly important to see regional wall motion

abnormalities. Endocardial definition can be enhanced by machine

controls to improve grey levels (such as harmonic imaging, gain,

and contrast) or probe position (increased pressure, better contact,

slight changes in window). If these factors make no difference,

intravascular contrast agents provide excellent border definition.

202

CHAPTER 4 Transthoracic chambers and vessels

3D volumetric measures

3D echocardiography is an advance on Simpson’s method as it allows con-

touring of the cavity within the 3D space of the echocardiographic volume

acquisition. Therefore there is no need to assume that the short axis view

of the ventricle follows the shape of a circle (or oval) and sum together a

‘stack of discs’. Instead you can contour the actual shape of the ventricle

in all dimensions.

• In order to process full volume data sets, a 4D semi-automated

contour detection program with manual correction options written

specifically for the left ventricle is needed.

• Commercially available scanners contain software tools which allow

the assessment of left ventricular volumes and ejection fraction. An

alternative is off-line processing with a commercially available software

package (4D-LV Function, TomTec, Germany) that is able to process

3D datasets from different scanner systems.

• After acquisition of a 3D dataset, sliced planes are viewed in

4-chamber view, 2-chamber view, and one or more short axis views

(C-planes) (Figs. 4.6 and 4.7).

• The left ventricular volumes are calculated by summing the areas

for each slice through the complete volume data set (volumetric 3D

echo).

How to get optimal 3D volumes

• Good image quality on 2D echocardiography is important when

selecting patients to undergo 3D image acquisition.

• If the endocardial definition is poor then a left-sided contrast agent

can be used (b p.561).

• Full volume datasets are triggered from the ECG trace and so it is

important that the patient has a regular heart rhythm.

• To reduce the incidence of stitch artefacts the probe and patient

position should be maintained in a stable position.

• Acquisition with the patient holding their breath is advised if the full

volume dataset is going to be acquired over several heartbeats.

204

CHAPTER 4 Transthoracic chambers and vessels

Acquisition of 3D volume for assessment of LV

• Position the probe at the apex in the same position as for acquisition

of 2D 4-chamber view. Modified windows may be used if selected

parts of the left ventricle need to be assessed.

• A biplane preview screen is used so that the 4- and 2-chamber views

can be seen simultaneously to help avoid foreshortening, see Fig. 4.6.

• Depth, gain, and TGC are adjusted in 2D imaging in order to achieve

the best possible endocardial definition.

• For full volume datasets maximize the number of subvolumes (beats)

used to generate the 3D image according to patient breath holding

capabilities and the regularity of the heart rhythm. The greater the

number of subvolumes that can be acquired and effectively stitched

together without artefacts, the greater the temporal and spatial

resolution.

• Acquire a 3D dataset and then evaluate it for quality.

• Commercially available 3D scanners allow the acquired image to

be viewed on the machine in several short axis planes as well as

a rendered 3D volume. This is important in order to identify any

stitching artefacts which may have occurred.

• Assess endocardial visualization using the cropping tools of the

scanner.

• If not adequate, discard and acquire another. Keep doing this until you

are happy that you have a volume you will be able to post-process

effectively.

Preparing the dataset

Postprocessing systems will normally automatically display an apical

4-chamber view, 2-chamber view, and C-planes (short axis view). How

you then handle the images varies with the different software packages

but typically:

• The planes can then be adjusted by the operator to ensure the

4-chamber plane has been accurately identified and is unforeshortened.

Similarly the plane used to create the 2-chamber view can also be

adjusted.

• Once happy that the long axes of the heart have been identified the

ventricular volumes and ejection fraction can then be calculated. To do

this typically the operator is asked to:

• Identify the end-diastolic and end-systolic frame (some software

will require you to mark these frames).

• Identify anatomical points on the 4- and 2-chamber left ventricular

views (e.g. left ventricular walls, left ventricular apex, or mitral

valve, see Fig. 4.8) so that the semi automated programme can

delineate the left ventricular contour. The software then will

delineate the contours in the other slices and frames, see Fig. 4.9.

LEFT VENTRICULAR SIZE

205

Fig. 4.8 Setting anatomical landmarks for estimation of 3D end-diastolic volume

(Phillips QLAB). Once the appropriate frame for end diastole has been selected

and the image has been orientated to reduce foreshortening the post processing

programme prompts the operator to mark the basal septum (yellow dot), basal

lateral wall (red dot), basal anterior wall (purple dot), basal inferior wall (black dot),

and the apex (blue dot).

Fig. 4.9 Once the initial anatomical landmarks have been set, the post processing

programme will delineate the LV contour for view in the 4 chamber (top right),

2 chamber (top left) and short axis or C-Plane views (bottom left). In doing this a

17 segment model of the LV is created (bottom right). See W Video 4.3.

206

CHAPTER 4 Transthoracic chambers and vessels

Review of contouring and calculation of volumes

• Once the postprocessing package has completed contouring the left

ventricle (Fig. 4.10), check that it has accurately delineated the true

left ventricular border by slicing through the left ventricular cavity

in the short axis planes and make corrections if you observe major

deviations.

• The end-diastolic, end-systolic volumes, stroke volume, and ejection

fraction are judged as in 2D echocardiography.

• Visually assess the regional left ventricular wall motion in the standard

apical and serial short axis views to ensure that the calculated ejection

fraction is similar to what the operator would expect visually.

• The left ventricular volume can be subdivided into 16 or 17

subvolumes. These create a pyramid volume with the peak in the

centre of the left ventricle, which is often coloured in by the software

(Fig. 4.11).

• The end-diastolic, end-systolic volumes and ejection fraction can

be assessed for each of the subvolumes, but the generally accepted

normal values are not yet available. At present the display of the

subvolumes helps to visualize regional wall motion abnormalities in

conjunction to the findings in the 2D cut planes.

• The timing of peak contraction can be assessed using the subvolume

curves (Fig. 4.11).

• The 3D analysis software measures the time from end-diastole until

the smallest left ventricular volume is recorded (lowest point of the

curve) and calculates the mean and standard deviation.

Left ventricular size: 3D normal ranges

Upper normal values (mean + 2 standard deviations [SD])

• LV end-diastolic volume index (LVEDVI): 82mL/m2

• LV end-systolic volume index (LVESVI): 38mL/m2

Lower limit (mean – 2 SD)

• LVEF: 49%

For left ventricular subvolumes no generally approved normal values

have been established.

EF, ejection fraction; LVEDVI, LV end-diastolic volume index; LVESVI, LV end-

systolic volume index.

208

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular size:

2D normal ranges (Table 4.1)

Table 4.1 Ranges for measurement of left ventricular size. (Adapted

from Recommendations for Chamber Quantification: A Report

of the American Society of Echocardiography Guidelines and

Standards Committee and the Chamber Quantification Writing

Group, Developed in Conjunction with the European Association of

Echocardiography. J Am Soc Echocardiogr 2005; 18: 1440-1463.)

Part 1, Values for women

Women

Normal

Mild

Moderate

Severe

LV dimension

LV d diameter, cm

3.9-5.3

5.4-5.7 5.8-6.1

>6.1

LV d diameter/BSA, cm/m2 2.4-3.2

3.3-3.4 3.5-3.7

>3.7

LV d diam/height, cm/m

2.5-3.2

3.3-3.4 3.5-3.6

>3.7

LV volume

LV d vol, mL

56-104

105-117 118-130

>130

LV d vol/BSA, mL/m2

35-75

76-86 87-96

>96

LV s vol, mL

19-49

50-59 60-69

>69

LV s vol/BSA, mL/m2

12-30

31-36 37-42

>42

Linear method: fractional shortening

Endocardial, %

27-45

22-26 17-21

<17

Mid wall, %

15-23

13-14 11-12

<11

2D method

Ejection fraction, %

>54

45-54 30-44

<30

BSA, Body surface area; d, diastolic; s, systolic.

Bold rows identify best validated measures.

LEFT VENTRICULAR SIZE: 2D NORMAL RANGES

209

Table 4.1 (Contd.)

Part 2, Values for men

Men

Normal

Mild

Moderate

Severe

LV dimension

LV d diameter, cm

4.2-5.9

6.0-6.3 6.4-6.8

>6.8

LV d diameter/BSA, cm/m2 2.2-3.1

3.2-3.4 3.5-3.6

>3.6

LV d diameter/height, cm/m 2.4-3.3

3.4-3.5 3.6-3.7

>3.7

LV volume

LV d vol, mL

67-155

156-178 179-201

>201

LV d vol/BSA, mL/m2

35-75

76-86 87-96

>96

LV s vol, mL

22-58

59-70 71-82

>82

LV s vol/BSA, mL/m2

12-30

31-36 37-42

>42

Linear method: fractional shortening

Endocardial, %

25-43

20-24 15-19

<15

Mid wall, %

14-22

12-13 10-11

<10

2D method

Ejection fraction, %

>54

45-54 30-44

<30

BSA, Body surface area; d, diastolic; s, systolic.

Bold rows identify best validated measures.

210

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular thickness and mass

All measurements of left ventricular mass are based on the principle of

estimating the difference between the epicardial and endocardial left

ventricular volumes and then calculating the mass of this ‘shell’ using the

known myocardial density (i.e. multiplication of the volume by 1.05). The

measurement techniques are the same as for quantification of left ven-

tricular size (b p.196). However, they are applied to obtain both a cavity

volume and a total volume. Measurements are done at end-diastole.

Linear measures of wall thickness can be reported directly or used

to estimate mass based on simple formulae but do not take account of

changes in left ventricular geometry. Volume measures are preferred and

3D echocardiography can also be used to assess mass as long as there is

good epicardial border definition.

Linear measures

Interventricular septum and posterior wall thickness

The simplest and most widely used assessments of left ventricular thick-

ness are interventricular septum and posterior wall thickness from M-mode

or 2D images (Fig. 4.12).

• In a parasternal long axis or parasternal short axis (mid papillary level)

drop an M-mode cursor through the ventricle perpendicular to the

walls at the level of the mitral valve leaflet tips.

• Identify the lines that relate to the septum and posterior wall and

measure the thinnest part (end-diastole).

• Report wall thickness and if increased consider further characterization

of hypertrophy (b p.218)

• Measurements can also be done directly from parasternal 2D images,

frozen in end-diastole. Measure with calipers from edge to edge.

Volume measures from linear measures

Teichholz method or prolate ellipse of revolution

Left ventricular mass can be estimated from linear dimensions (see b

‘Linear Measures’, p.210) using a ‘prolate ellipse of revolution’ formula.

Traditionally, this was based on M-mode measures. The equation uses

cubed measurements so slightly off-axis views or small errors in diam-

eter are amplified into large differences in volume. The method takes no

account of abnormal left ventricular morphology and is rarely used now.

• In parasternal long or short axis (mid papillary level) views obtain

measures of left ventricular end-diastolic diameter (LVEDD),

interventricular septum thickness (IVS) and posterior wall thickness (PWT).

• In an apical 4-chamber view obtain a measure of end-diastolic left

ventricular length (from apex to middle of mitral valve annulus).

• Left ventricular mass is automatically calculated using the formula:

⎤

0 8× 1 05

0.6

⎦

(the constants (0.8 and 0.6) improve the accuracy of the basic equation

(in bold) in studies based on postmortem hearts).

212

CHAPTER 4 Transthoracic chambers and vessels

2D volume measures (Fig. 4.13)

Area-length and ellipsoid models

There are two validated methods available for estimating left ventricular

mass based on the area-length formula (b p.200) and the truncated

ellipsoid model. Both methods use the same set of measurements in end-

diastole—total and cavity myocardial area (short axis view, mid-papillary

level) and left ventricle length (apical 2 chamber view)—and only vary in the

equation they use to estimate volumes.

• Obtain a clear parasternal short axis view (mid ventricle level) with

good endocardial and epicardial border definition.

• Record a loop and scroll through to the end-diastolic frame.

• Trace around the endocardial border and record the endocardial or

left ventricular cavity cross sectional area. Do not include the papillary

muscles in the tracing.

• Trace around the epicardial border and record the epicardial or total

cross sectional area.

• Myocardial area is the difference between the total cross-sectional area

and the cavity cross sectional area.

• In a non-foreshortened apical 2-chamber view record a loop and

identify the end-diastolic frame (when the ventricle is largest). Measure

the distance from apex to the middle of the mitral valve annulus.

Record the left ventricular length.

• The machine or off-line software will automatically calculate left

ventricular mass from these measurements.

• The truncated ellipsoid equation for a volume is:

cross-sectional area in parasternal short axis 2 3

ventricle lenght

Biplane Simpson’s model

It is possible to use a biplane Simpson’s method (b p.198) to calculate

mass from 2D images as long as epicardial border definition is good. The

accuracy of the technique is dependent on obtaining a clear epicardial bor-

der in both planes but, unlike other methods, will take account of regional

wall motion abnormalities or asymmetric variation in wall thickness. The

principle behind this technique is also the basis for how mass is measured

in 3D echocardiography. To undertake this with 2D:

• Measure total end-diastolic left ventricular volume using Simpson’s

method by tracing the epicardial border in apical 4- and 2-chamber

views.

• Subtract left ventricular end-diastolic volume assessed with Simpson’s

method from this total volume. Multiply the difference by 1.05 to

obtain a left ventricular mass.

214

CHAPTER 4 Transthoracic chambers and vessels

3D volume measures

3D assessment of mass is an improvement on the 2D biplane Simpson’s

approach to assessment of mass but instead of just using 2 planes the

contours of the epicardial and endocardial ‘shells’ are identified in 3D

by automated software. This technique of measuring the volume in 3D

is a key reason why left ventricular mass can be measured so accurately

with cardiovascular magnetic resonance. With good image quality, 3D left

ventricular mass measures with echocardiography are now as good as gold

standard techniques. To measure left ventricular mass with 3D:

• Acquire a 3D apical full volume data set, see b p.202.

• Continue to discard and acquire full volumes until you are happy

you have the best quality 3D dataset without artefact and with good

border definition.

• Load the dataset into postprocessing software. This will display the left

ventricle in the standard views, typically, 4-chamber, 2-chamber, and

short axis stack.

• The exact approach to analysis depends on the software package.

However, typically (Fig. 4.14).

• In the 4-chamber view the operator will have to mark the mitral

valve hinge points and contour the end diastolic endocardial

border.

• The operator then identifies the contour of the outer ventricular

wall.

• This procedure is repeated for the 2-chamber view.

• The software package then automatically estimates the end-

diastolic volumes and, base to apical length to generate a measure

of left ventricular mass.

216

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular thickness and mass:

normal ranges (Table 4.2)

Table 4.2 Ranges for measurement of left ventricular mass.

(Adapted from Recommendations for Chamber Quantification:

A Report of the American Society of Echocardiography Guidelines

and Standards Committee and the Chamber Quantification Writing

Group, Developed in Conjunction with the European Association of

Echocardiography. J Am Soc Echocardiogr 2005; 18: 1440-1463.)

Part 1, Values for Women

Women

Normal Mild

Moderate Severe

Linear method

LV mass, g

67-162

163-186

187-210

>210

LV mass/BSA g/m2

43-95

96-108

109-121

>121

LV mass/height, g/m

41-99

100-115

116-128

>128

LV mass/height2, g/m2

18-44

45-51

52-58

>58

Relative wall thickness, cm

0.22-0.42 0.43-0.47 0.48-0.52

>0.52

Septal thickness, cm

0.6-0.9

1.0-1.2

1.3-1.5

>1.5

Posterior wall thickness, cm 0.6-0.9

1.0-1.2

1.3-1.5

>1.5

2D method

LV mass, g

66-150

151-171

172-182

>182

LV mass/BSA, g/m2

44-s88

89-100

101-112

>112

BSA, Body surface area.

Bold rows identify best validated measures.

218

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular hypertrophy

General

The clinical importance of left ventricular mass relates to identification of

pathological left ventricular hypertrophy. Left ventricular hypertrophy can

occur secondary to other pathology (e.g. aortic valve disease or hyperten-

sion), or be a primary problem with the myocardium (e.g. hypertrophic

cardiomyopathy, infiltrative cardiomyopathy). With hypertrophic cardio-

myopathy there may be asymmetric changes with septal or apical changes.

Physiological hypertrophy is also found (e.g. athletes or in pregnancy) that

is thought to be reversible. In the elderly there is sometimes septal angula-

tion and thickening which creates the impression of septal hypertrophy

but left ventricle mass is usually unchanged.

Assessment

If hypertrophy is present base further assessment on: (1) a description of

the pattern (global or asymmetric) (Fig. 4.15), (2) a description of severity

using overall mass and mass relative to ventricular size, (3) characteri-

zation of related pathology (e.g. valve disease or outflow tract obstruc-

tion) and unusual appearances (e.g. speckling texture of amyloid, localized

hypertrophy of tumour).

Appearance

• Using all views make a qualitative judgement of hypertrophy.

Parasternal short axis view is good for seeing concentric hypertrophy.

Parasternal long axis and apical 5-chamber views pick up septal

hypertrophy. Apical and subcostal views can look for apical

hypertrophy. Report the pattern and, if asymmetric, wall thickness

measures at different points.

• A common reported abnormal texture is amyloid ‘speckling’. This can

be influenced by contrast and gain settings. Localized hypertrophy with

abnormal echolucency might suggest malignant infiltration.

Grading severity

Left ventricular mass can be clinically graded into 4 categories: (1) normal,

(2) increased relative wall thickness with increased mass (concentric left

ventricular hypertrophy), (3) increased mass with normal relative wall

thickness (eccentric left ventricular hypertrophy) or (4) normal mass with

increased relative wall thickness

(concentric remodelling). Concentric

changes suggest pressure overload (e.g. due to aortic stenosis or hyper-

tension). Eccentric changes suggest volume overload (e.g. due to aortic

regurgitation). Grade severity by reporting overall mass and/or wall thick-

ness, and relative wall thickness.

• Overall severity: Fig. 4.15 provides a guide to grading hypertrophy

based on mass and wall thickness measures.

• Relative wall thickness: use left ventricular posterior wall thickness

(PWT) and left ventricular end diastolic diameter (LVEDD). Relative

wall thickness is calculated as: (2 × PWT)/LVEDD.

• If relative wall thickness is >0.42 report concentric hypertrophy.

• If relative wall thickness is <0.42 report eccentric hypertrophy.

220

CHAPTER 4 Transthoracic chambers and vessels

Hypertrophic cardiomyopathy

General

Hypertrophic cardiomyopathy describes marked left ventricular hyper-

trophy secondary to specific genetic abnormalities. There are multiple

gene defects that lead to hypertrophy and more are being identified. The

responsible genes commonly control muscle fibre function. The hypertro-

phy can be of many different patterns and towards the end of the disease

process left ventricular failure can develop (in 10% of cases). The classic

pattern is of marked septal hypertrophy (Fig. 4.16) associated with sig-

nificant outflow obstruction. LVOT obstruction occurs in about a quarter

of patients. Symptoms of breathlessness may be due to any or a com-

bination of: reduced diastolic or systolic left ventricular function, mitral

regurgitation, left LVOT obstruction or microvascular dysfunction.

Assessment

• If hypertrophic cardiomyopathy is suspected report the pattern and

measures of wall thickness, relative wall thickness and mass.

• Assess the LVOT at rest and consider exercise-induced gradients.

• Report left ventricular systolic and diastolic function and look at mitral

valve function and regurgitation.

• Assessment of strain or myocardial velocities using TDI or speckle

tracking may help identify impaired cardiac function prior to cardiac

hypertrophy.

Left ventricular outflow

Historically, M-mode has been used to demonstrate outflow obstruction.

• Systolic anterior motion of mitral valve is seen with M-mode placed

through the mitral leaflets. It is considered severe (i.e. obstructive)

if the leaflet touches the ventricular septum or the outflow tract is

narrowed by the anterior mitral valve leaflet for >40% of systole.

• Obstruction tends to be in mid to late systole leading to a drop in

flow through the aortic valve towards the end of systole. Therefore,

an M-mode trace through the aortic leaflets can demonstrate early

closure of the valve and the valve may appear to flutter as flow drops.

Doppler should be used as the main method to quantify obstruction.

• In an apical 5- or 3-chamber view place colour flow mapping over the

outflow tract. This may demonstrate turbulent, high velocity, flow (an

irregular scattering) in the outflow tract.

• In the apical 5-chamber view align the CW Doppler through the

outflow tract, aortic valve, and aorta. Record a spectral trace to obtain

peak and mean velocities. The trace may appear as a scimitar shape

demonstrating the classic, late, dynamic obstruction (Fig. 4.17).

• Place PW Doppler at the bottom of the outflow tract and move it

towards the valve. If the gradient is due to hypertrophy the peak

velocities will be present in the outflow tract below the valve and the

trace will start aliasing due to the high velocities.

• In a symptomatic patient—particularly if symptomatic on exercise—

without obstruction, an exercise stress protocol can be used and

outflow tract gradient measured at peak exercise.

222

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular non-compaction

• Left ventricular non-compaction is an inherited condition characterized

by marked left ventricular trabeculation (Fig. 4.18) within the left

ventricular apex and if more pronounced extending towards the

midventricular or even basal segments.

• The inferior and lateral segments are more commonly affected than

the septum.

• Left ventricular non-compaction may lead to impaired ventricular

function and can be a substrate for left-sided thrombi and arrhythmias.

To identify non-compaction left-sided contrast agents are helpful. In

apical views the trabeculation is seen as a partially contrast-filled layer.

Report the thickness of the trabeculation relative to the myocardium.

• A ratio of >2:1 of the non-compacted (trabeculations) myocardium

to compacted (normal) myocardium at end-systole suggests left

ventricular non-compaction. Colour Doppler often demonstrates

flow between the trabeculations. Cardiovascular magnetic resonance

imaging aids diagnosis.

224

CHAPTER 4 Transthoracic chambers and vessels

Restrictive cardiomyopathy

True restrictive cardiomyopathy is rare and tends to occur due to infiltra-

tive disease such as amyloidosis. Symptoms develop due to myocardial

thickening and stiffening leading to diastolic dysfunction. Late in the disease

systolic dysfunction can develop as contractile function diminishes.

• A full assessment of the left ventricle (size and mass, systolic

and diastolic function; b p.246) is needed for diagnosis. Classic

appearance is normal systolic function and cavity dimensions but

abnormal diastolic function with varying increases in wall thickness.

• The usual diagnostic conundrum is differentiation from constrictive

pericarditis. Techniques such as tissue Doppler imaging and mitral

inflow are useful and described in the pericardium section on b p.302.

Dilated cardiomyopathy

Dilated cardiomyopathy describes left ventricular dilatation and impaired

function and can be accompanied by right ventricular dilatation. There can

be many underlying causes, such as ischaemic heart disease, tachycardia-

induced, metabolic conditions (e.g. hyperthyroidism, phaeochromocytomas),

postpartum, or post-myocarditis. The term idiopathic dilated cardiomyop-

athy is used if no underlying cause is identified. Echocardiography should

provide information on ventricle size and function and, be used for follow-

up to gauge recovery or deterioration.

Myocarditis

Myocarditis occurs due to a viral infection either acutely or as a post-viral

phenomenon. It can affect left ventricular global systolic function with or

without left ventricular dilatation and can range from mild to severe. A peri-

cardial effusion may also develop. LV dysfunction can resolve, stabilize, or

deteriorate and myocarditis is a common cause for dilated cardiomyopathy.

Recovery is assessed by repeated echocardiography to determine changes

in left ventricular function. Cardiovascular magnetic resonance imaging may

be useful to determine the degree of myocardial damage.

MYOCARDITIS

225

3D echocardiography in cardiomyopathies?

Real-time 3D echocardiography has advantages over 2D echocardiog-

raphy which may be helpful in the assessment of patients with cardio-

myopathies:

• It permits more accurate assessment of ventricular volumes.

• 3D imaging allows detection of early changes in myocardial

mechanics prior to changes in conventional measures of ventricular

function with the use of 3D speckle tracking. This has been shown

to provide results similar to that for 2D speckle tracking although as

real-time 3D uses only one apical view rather than multiple views,

post-processing is less time consuming.

• For the assessment of cardiomyopathies with poor ventricular

function, real-time 3D has been used to quantify left ventricular

mechanical dyssynchrony to identify patients who may be suitable for

cardiac resynchronization therapy.

• In patients with hypertrophic cardiomyopathy, 3D echocardiography

has been shown to provide important insights into the mechanics

and deformational geometry of the left ventricular outflow tract.

3D echocardiography has helped to show that in patients with

hypertrophic cardiomyopathy and systolic anterior motion of the

mitral valve the anterior segment of the anterior mitral valve leaflet

causes the development of the left ventricular outflow tract gradient.

• In patients with apical hypertrophic cardiomyopathy, 3D

echocardiography allows cropping to visualize the left ventricular

apex in multiple directions planes to help assess for hypertrophy.

• The use of 3D echocardiography in the diagnosis of left ventricular

non-compaction has also been reported. By rotating and cropping

the dataset it allows the extent of non compaction to be determined

in a segmental approach.

226

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular function

Assessment of left ventricular function is one of the most frequently

requested echocardiography studies, with ejection fraction the most

sought after parameter. This is driven by several issues:

• The number of patients presenting with dyspnoea and possible

congestive heart failure is increasing, there is clear prognostic

significance to the parameter of ejection fraction.

• To help guide therapy (especially decisions for device therapy in heart

failure and surgery for valve disease). Remember that congestive

heart failure is a clinical diagnosis and even before clinical signs are

evident abnormalities of left ventricle function may be apparent. Early

detection is critical to prevent progression of heart failure.

Assessment

An assessment of left ventricle function should be comprehensive. Box 4.1

outlines the techniques for a complete examination. Not all will be felt nec-

essary for all patients and selection should be based on the clinical indication

for the study. However, the minimal requirements are an assessment of:

• Left ventricle size and shape.

• Systolic function, including regional differences.

• Diastolic function.

LEFT VENTRICULAR FUNCTION

227

Box 4.1 Assessment of left ventricular function

• Global systolic function:

• Subjective evaluation of size, shape, regional and global function.

• Measurement of left ventricle volumes/dimensions, ejection

fraction (Simpson’s or 3D).

• Doppler: volumetric measurements, dP/dt in patients with mitral

regurgitation.

• New techniques for myocardial function (strain, strain rate).

• LV response to exercise stress.

• Left ventricle shape and wall stress.

• Regional systolic function:

• Subjective evaluation of segmental function, wall motion score.

• Myocardial contrast enhancement.

• Diastolic function:

• Transmitral flow categorization.

• Strategies for recognition of pseudonormal filling.

• LA size (area or volume).

• Annular tissue Doppler (E/E’).

• Response to Valsalva manoeuvre.

• Others (pulmonary vein flow, mitral flow propagation).

• Synchrony:

• M-mode intraventricular delay.

• Doppler assessment of interventricular delay.

• Tissue Doppler imaging.

228

CHAPTER 4 Transthoracic chambers and vessels

Global systolic function

Left ventricular systolic evaluation is commonly performed by eye. Although

the eyeball of an experienced reader is equivalent to the trackball, the

desirability of visual assessment is dependent on the circumstances. Visual

assessment alone is appropriate in an emergency but inappropriate in

most circumstances when elective decisions are being made. Global systo-

lic function should be quantified. The standard approaches are detailed

here and the most accurate (and therefore the preferred methods) are

based on volumetric measures (b p.198).

2D measures

Ejection fraction

This represents the fraction of blood within the left ventricle which is eject-

ed in 1 cardiac cycle (Fig. 4.19). To calculate, use the end-diastolic (LVEDV)

and end-systolic (LVESV) volumes (b p.198). The ejection fraction is:

LVEDV LVESV

×100%

LVEDV

EF can be calculated from linear measures (b p.196) using Teicholz’ equa-

tion, but this is notoriously inaccurate, especially if regional function is

reduced. If apical images are suboptimal, use of LV opacification may per-

mit measurement using Simpson’s rule, and 3D imaging may be performed

from the parasternal window. Teicholtz equation:

LVEDD LVESD³

×100%

LVEDD

Fractional shortening (fractional area change)

Fractional shortening and fractional area change represent summary meas-

ures of changes in left ventricle size in mid cavity. Fractional shortening is

based on the standard linear measures (Fig. 4.20 and b p.196):

LVEDD LVESD

×100%

LVEDD

Fractional area change (Fig. 4.21) uses end-diastolic (LVEDA) and end-

systolic (LVESA) cavity cross-sectional area traced in parasternal short

axis (mid-ventricle level) view (to measure area see b p.199):

LVEDA LVESA

×100%

LVEDA

230

CHAPTER 4 Transthoracic chambers and vessels

3D measures

• Inaccuracy of the earlier described measurements is inherent in

the projection of the 3D structure of the heart in 1D or 2D, which

necessitates both geometric assumptions and appropriate plane

location.

• These considerations are especially important for repeat imaging,

for which exact plane duplication is almost impossible. A wealth of

evidence supports 3D to be a more accurate means of obtaining LV

volumes than standard imaging—although the benefit is less marked

for EF.

• Patients most likely to benefit are those with ischaemic cardiomyopathy

and those having repeat studies. There remains some underestimation

of LV volumes due to suboptimal resolution of trabeculations.

• Further technical developments are needed to improve imaging quality

and frame rate, but the technique is ready for routine use.

Doppler evaluation

Stroke volume and cardiac output

• Doppler measurements of stroke volume are more commonly written

about than performed.

• The volume of blood that forms the ejection fraction (LVEDV − LVESV)

represents the stroke volume. Normally this is around 75-100mL.

These measures vary with body size and should be divided by body

surface area (body surface area = sq root(height (m) × weight

(kg)/36)) to give a stroke volume index (normally 40-70mL/m2) and

cardiac index (normally 2.5-4L/min/m2) respectively.

• If the mitral valve is competent then this can be multiplied by heart

rate to calculate cardiac output. Normally this is around 4-8L/min.

• Stroke volume may be derived from EDV and ESV measures, but this

depends on good image orientation.

• Doppler may be useful for stroke volume assessment (Fig. 4.22), but

depends on accurate outflow tract measures (errors of which are

squared to calculate area).

• Measurement of dP/dt can be a useful extra measure in patients with

severe mitral regurgitation.

Calculating stroke volume

• In apical 5-chamber view record a PW Doppler in the outflow tract

and trace the shape. Record the velocity time integral (vti).

• In a parasternal long axis view, zoom the LVOT and measure the

width (edge to edge, just below aortic valve).

• Stroke volume is the area of the outflow tract (π x [LVOT

diameter/2]2) multiplied by the outflow tract vti.

• Cardiac output is stroke volume multiplied by heart rate.

232

CHAPTER 4 Transthoracic chambers and vessels

dP/dt

dP/dt describes the rise in intraventricular pressure during early systole

(Fig. 4.23). The change in pressure is determined by systolic contrac-

tion so the faster the rise the better the left ventricular systolic function.

Theoretically this should be less dependent than ejection fraction on the

loading condition of the heart. It can only be measured if there is signifi-

cant mitral regurgitation.

• In an apical 4-chamber view align the CW Doppler through the mitral

valve and the associated regurgitant jet.

• Record a spectral trace at a sweep speed of 100mm/s to broaden the

tracing. Set the scale to focus on the 0 to 4m/s range.

• Measure the time taken for the velocity of the regurgitant jet to rise

from 1 to 3m/s (the measure has been standardized for this pressure

rise from 4 to 36mmHg). The machine or software will normally

automatically calculate dP/dt if the 1m/s and 3m/s points are marked

although it can be calculated by hand.

• dP/dt >1200mmHg/s (roughly <27ms between points) relates to

normal function and <800mmHg/s (roughly >40ms) is severely

depressed function.

Left ventricular outflow vti

To gain an impression of whether cardiac output is normal, low, or high

measure vti in the left ventricular outflow tract using PW Doppler from

an apical 5-chamber view. In the general population if the heart rate is

between 60-100 then normal range is 18-22. This technique can also be

applied to assess right ventricular output using PW Doppler in the right

ventricular outflow tract in a parasternal short axis view. Normal values

should be 76% (or three-quarters) of left ventricle outflow vti.

234

CHAPTER 4 Transthoracic chambers and vessels

Regional systolic function

Although regional changes can occur in cardiomyopathies, the most com-

mon cause of regional left ventricle dysfunction is coronary artery disease.

Regional abnormalities are usually assessed by eye and are dependent on

operator experience. Basic assessment is of wall movement in coronary

artery territories. This should be refined to gauge movement of wall seg-

ments and can then be semi-quantified with wall motion scores. There are

fully quantitative methods although not yet in routine clinical practice.

Qualitative assessment

The key to reporting regional dysfunction is to use a standard system

to segment the heart. The standard 16-segment model of the American

Society of Echocardiography (septal, lateral, anterior, and inferior at the

apex, as well as anteroseptal and posterior segments at the base and mid-

papillary muscle level) is still widely used, although the American Heart

Association has moved to a 17-segment model (which includes a true

apical segment) to encourage similar segment models between imaging

techniques (Fig. 4.25).

Wall motion

• Record parasternal long and short axis and, apical 4-, 3-, and

2-chamber views. Avoid foreshortening and ensure a clear endocardial

border. Enhance the border with left-sided contrast agents if needed

(see b p.561).

• Generally: anterior wall, apex, and septum are supplied by the left

anterior descending artery; lateral and posterior (inferolateral) walls

by the circumflex artery; and inferior wall by the right coronary artery.

However, basal septum in an apical 4-chamber view is right coronary

artery territory and supply of the apex and posterior wall varies

slightly depending on which coronary system is dominant (left or right)

(Fig. 4.24).

• In each loop look at each segment and score as normal, hypokinetic

(endocardial excursion <5mm), akinetic (endocardial excursion

<2mm), or dyskinetic (endocardium moves out in systole).

• As movement may be passive, look for thickening in segments you are

unsure about. Normal segments will thicken by >50% between diastole

and systole. If present, report as normal or hypokinetic.

• Present the findings as a diagram.

Wall motion scores

Wall motion scoring permits semi-quantitative evaluation of the regional

function assessment.

• Score normal regions as 1; hypokinestic as 2; akinetic as 3; and

dyskinetic as 4. Score aneurysms as 5; and thinning with akinesis as 6;

or thinning with dyskinesis as 7.

• Calculate (or let the software calculate) a wall motion score index by

averaging scores of all individual segments. This is a semi-quantitative

index of global systolic function analogous to ejection fraction.

236

CHAPTER 4 Transthoracic chambers and vessels

Quantitative assessment

Concordance of wall motion assessment between centres may be improved

with the use of standard reading criteria, but remains imperfect. The benefit

of a suitable objective measure would be to supplement wall motion scoring

and help less expert readers.

Quantitation of regional function has been performed with a number of

echocardiographic and Doppler modalities (Table 4.3). Although some are

encouraging, none have entered mainstream practice.

Table 4.3 Assessment techniques for regional function

Radial

Longitudinal

Displacement and

Centre-line (from 2D)

Annular M-mode

thickening

Color kinesis

Tissue tracking

Anatomical M-mode

Speckle

Speckle or TDI

Velocity

Speckle

TDI or speckle

Deformation

Speckle

TDI or speckle

Timing

TDI (time to peak systole

or onset of diastole)

APICAL CAP

APICAL INFERIOR

APICAL ANTERIOR

APICAL SEPTUM

APICAL LATERAL

(ANTEROSEPTUM)

MID SEPTUM

MID LATERAL

MID INFERIOR

MID ANTERIOR

(INFEROSEPTUM)

(ANTEROLATERAL)

BASAL SEPTUM

BASAL LATERAL

BASAL INFERIOR

BASAL ANTERIOR

(INFEROSEPTUM)

(ANTEROLATERAL)

Apical Two Chamber

Apical Four Chamber

APICAL CAP

ANTEROSEPTUM

APICAL LATERAL

APICAL SEPTUM

(ANTEROSEPTUM)

ANTEROLATERAL

MID INFEROLATERAL

MID SEPTUM

(POSTERIOR)

(ANTEROSEPTUM)

INFEROSEPTUM

BASAL INFEROLATERAL

BASAL SEPTUM

(POSTERIOR)

(ANTEROSEPTUM)

INFERIOR

INFEROLATERAL

Parasternal Short Axis

Apical Three Chamber or

(all MID Segments)

Parasternal Long Axis

X marks the distinct seventeen segments (some are seen in multiple views)

Fig. 4.25 17-segment model (16-segment is the same without the apical cap). Note that some segments are seen in multiple views. The posterior wall can also

be referred to as the inferolateral wall. ‘X’s mark the 17 different segments of the ventricle, some of which are seen in the other views (unmarked segments).

238

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular strain

Background

Strain is a fundamental physical property of myocardium that reflects its

deformation under an applied force. Two methods are used: (1) tissue

Doppler—which derives strain from strain rate, a gradient of adjacent

velocities over a sampling distance, and

(2) speckle tracking—which

derives strain from excursion of the speckles.

Complete assessment of strain—radial, longitudinal, circumferential, and

the shear stress—may be achievable but is likely to be too much informa-

tion for routine clinical use. The most robust and reproducible measure is

longitudinal strain, for which there is the most clinical data. Circumferential

strain (Figs. 4.26 and 4.27) can be assessed with speckle tracking but radial

strain is difficult to measure by any method.

Which technique?

• Speckle strain is simpler and provides strain in multiple dimensions—

potentially in 3D. Speckle strain is the preferred option apart

from when high frame-rate is needed (e.g. for strain rate or stress

imaging), in which case tissue velocity is likely superior.

• Neither tissue velocity nor speckle techniques are perfect and

require further development—for example, studies suggest strain

values in the same myocardium differ depending on the machine.

Global strain

• Although ejection fraction is simple and intuitive, as well as being

supported by a wealth of prognostic information, it has important

limitations including image quality dependence, geometric assumptions,

load dependence, and insensitivity to early disease (which is

characterized by disturbances of longitudinal function).

• Global strain avoids inaccuracy due to inaccurate border tracing, but is

dependent on both loading conditions and image quality.

• Global strain is an analogue of ejection fraction, and can be measured

as either longitudinal (GLS) or circumferential strain (GCS), derived

as the mean of interpretable regional strains. These parameters have

predicted outcome in two studies.

• Global strain is likely to be of value for sequential studies (e.g. left

ventricular response to therapy), and the detection of early disease

(e.g. infiltration, cardiotoxicity).

• Global strain is the average of the strain measurements in all 16 or 17

myocardial segments (or the segments where strain measurements are

available).

LEFT VENTRICULAR STRAIN

239

Normal values for strain measurements

By convention, shortening is described by a negative value and lengthening

by positive strain. If the myocardium did not contract then strain would

be 0. Longitudinal strain is the most robust clinically and normal regional

peak systolic strain in the longitudinal direction is approximately −18%.

Longitudinal strain values of −14% or even closer to 0 are probably

abnormal and a global longitudinal strain of −12% corresponds to an EF

<35%. So far there is only very limited data available on normal ranges

for all the parameters but the values given here have been published as

normal ranges (mean ± SD) for the different types of strain (modified

from Saito K et al.1). Note longitudinal and circumferential strain are

negatives as the left ventricle reduces in size during systole, whereas,

because radial strain describes thickening of the myocardium in systole,

it is positive.

3D speckle tracking*

2D speckle tracking

Longitudinal, %

−17.0±5.5

−19.9±5.3

Circumferential, %

−31.6±8.0

−27.8±6.9

Radial, %

34.4±11.4

35.1±11.8

3DT=3D speckle tracking; 2DT=2D speckle tracking, *Artida (Toshiba)

Reference

1 Saito K et al. Comprehensive evaluation of left ventricular strain using speckle tracking

echocardiography in normal adults: comparison of three dimensional and two dimensional

approaches. Am Soc Echocardiogr 2009; 22(9): 1025–30.

240

CHAPTER 4 Transthoracic chambers and vessels

Regional strain

• The most important application of regional strain is to the recognition

of ischaemic heart disease. The recognition of scar (resting imaging),

viability (low-dose response), and ischaemia (peak dose imaging) is

subjective and depends on image quality and observer expertise. Strain

may offer a sensitive and reproducible alternative.

• The use of strain to recognize resting wall motion abnormalities may

improve the detection of coronary disease in the ICU, operating room,

and Chest Pain Unit (cut-offs of −0.83/s for strain rate and −17.4% for

strain have been proposed).

• Diastolic strain disturbance may persist for hours and represent a

potential ‘ischaemic memory’ signal. Strain has also been used to

anticipate the transmural extent of scar.

• The augmentation of viable segments in response to dobutamine may

also be quantified with strain. Speckle strain appears to be inferior to

Doppler-based strain, especially in the basal segments, possibly due to

image quality.

• The assessment of strain during ischaemia remains extremely difficult.

A human study has shown an increment of both sensitivity and

specificity by combination of strain rate with wall motion. However,

Doppler-based strain rate is onerous and subject to artefact, and

speckle-based imaging is limited by image quality and frame-rate.

• The application of strain to the timing of regional contraction

(mechanical dispersion) has potential applications in cardiac

resynchronization therapy and possibly in the prediction of ventricular

arrhythmias.

• Other strain applications that will likely assume importance are RV and

atrial strain.

Advantages and disadvantages of strain imaging

The advantages of strain include:

• A sensitive and automated marker of regional and global function.

• It is relatively homogeneous in different LV segments.

• It is a marker of contractility.

• It is independent of tethering.

The disadvantages of strain include:

• Methods are time-consuming, complex, and require a knowledgeable

user to avoid misleading results due to artefact.

• Speckle strain is dependent on good image quality.

• Tissue velocity requires imaging of the structure as close as possible

to the ultrasound beam.

242

CHAPTER 4 Transthoracic chambers and vessels

Strain assessment by 2D speckle tracking

Image acquisition

• Good 2D image quality is necessary to ensure clear visualization of the

endocardium.

• For complete 2D strain analysis all of the standard views for

assessment of left ventricular regional wall motion will need to be

acquired: left ventricular parasternal view; left ventricular short axis

view (basal, mid and apical level) and left ventricular apical 4-, 3-, and

2-chamber views.

• Optimize the 2D image, adjusting the sector size, and depth to focus

on the left ventricle.

• Ensure the frame rate is between 50-90 frames/s.

• Acquire images at end expiration.

Postprocessing

• A number of postprocessing software packages exist.

• After loading the appropriate view of the left ventricle the software

package will ask the operator to confirm which view it is.

• Some software packages allow the gain of the image to be altered

again if necessary.

• The operator will be prompted to identify specific points on the image

to mark (usually up to 3 points). From this the software automatically

will delineate the endocardial and epicardial borders (Fig. 4.26).

• The image can then be played. It is important that the operator

visually assesses how well the automated borders are tracking the true

endocardium/epicardium through the cardiac cycle.

• If the tracking is poor it will be necessary to adjust the automated

border as required.

• When happy, the operator can then select which type of strain is to be

analysed (Fig. 4.27).

• A colour overlay which corresponds to the colour bar on the left of

the screen will be seen (see Fig. 4.28).

Each image of the left ventricle which is being assessed will be displayed

segmentally and also displayed on a segmental strain graph.

244

CHAPTER 4 Transthoracic chambers and vessels

Strain assessment by 3D speckle tracking

Image acquisition

• For adequate 3D speckle tracking analysis it is important that the 2D

windows are good so that the endocardial border can be seen.

• Once the optimal 2D left ventricular apical 4-chamber view has been

obtained, select 3D view.

• 3D full volume acquisition mode should be used.

• In the biplane view, adjust the depth and sector width to ensure you

focus on the left ventricle.

• For 3D speckle tracking the image resolution should be optimized so

that an adequate frame rate is achieved. Adjust the line density and

use the maximal number of subvolumes (beats) possible depending on

patient breath-holding capabilities.

• Acquire a full volume at end expiration.

• Check for the presence of stitching artefacts in the 4-chamber view

and also by slicing the left ventricle to view in several short axis planes.

• If adequate, accept the image or else delete and start acquisition again.

Postprocessing

• Several different postprocessing software packages exist and whilst

there may be some variation in individual algorithms, the general

principles of estimating 3D strain are similar.

• Select the 3D full volume left ventricular acquisition to be used.

• The left ventricle will then be displayed in a number of planes—usually

an apical 4-chamber view, apical 2-chamber view, and 3 short axis

slices (Fig. 4.29).

• The left ventricular orientation in the biplane view can be adjusted to

correct for foreshortening.

• The level of the 3 short axis planes can also be adjusted to ensure that

the left ventricular apex, mid left ventricle (papillary muscle view), and

basal left ventricle are being displayed.

• The software package will then prompt the operator to identify

and mark anatomical landmarks (usually between 3-5) on the left

ventricular biplane view. The automated software will then delineate

the endocardium and epicardium in all of the on-screen left ventricular

views.

• The operator can then play the loop of the cardiac cycle to see

whether the epicardial and endocardial borders are being tracked

appropriately.

• In addition to end-diastolic volume, end-systolic volume, and ejection

fraction, the software calculates left ventricular mass. The left

ventricular mass is measured during the cardiac cycle and a flat curve

is an indicator for good tracking of the endocardium and epicardium

as it is consistent with mass being constant. The following values are

available within 30 seconds after initiating the analysis:

• Global and segmental displacement.

• Global and segmental strain strain rate, displacement.

• A special feature is 3D strain which probably comes closest to the

real movement of speckles.

• Rotation and twist.

246

CHAPTER 4 Transthoracic chambers and vessels

Diastolic function

Diastolic dysfunction is increasingly recognized as an important influence

on symptoms and haemodynamic status. Diastole extends from aortic

valve closure to mitral valve closure and has 4 distinct phases:

• Isovolumetric relaxation—before the mitral valve opens.

• Early filling—accounting for up to 80% of ventricular filling.

• Diastasis—as left atria and left ventricle pressures equalize.

• Atrial systole—accounting for the remainder of ventricular filling.

Diastolic dysfunction during the early phases is due to problems with

active myocardial relaxation. This is usually present early in disease devel-

opment (e.g. ischaemia, aortic stenosis, hypertension, hypertrophy) and

is termed abnormal relaxation. With disease progression, fibrosis devel-

ops and chamber compliance reduces (also seen with infiltrative disease).

These changes affect later diastole and lead to restrictive filling. During the

transition there is a period of apparently pseudonormal filling on some

echocardiographic parameters at the mitral valve although diastolic func-

tion remains impaired.

Assessment

Measurement of transmitral flow (left ventricular filling) is the cornerstone

of diastolic function evaluation (i.e. E/A ratio). This measure is refined with:

(1) pulmonary vein flow and left atrial size (to understand left atrial pres-

sure) and (2) tissue Doppler imaging of the mitral annulus (to study changes

in myocardial movement) (see Fig. 4.16). Colour M-mode propagation has

also been used. The report should comment on the presence and pat-

tern of diastolic dysfunction (abnormal relaxation, pseudonormal filling or

restrictive filling). Also comment on likely underlying pathology, if identified,

during the examination.

Mitral valve inflow

• In the apical 4-chamber view position the PW Doppler sample volume

at the mitral leaflet tips (Fig. 4.30). Use colour Doppler if necessary to

optimize beam alignment with mitral inflow. Record a tracing.

• E/A ratio: measure peak E-wave velocity and peak A-wave velocity.

Normal filling is generally characterized by an E/A ratio of 0.75-1.5.

• Other measures:

• Deceleration time: measure the distance from start to end of the

E-wave. If the end is obscured by the A-wave extrapolate the slope

to the baseline. A deceleration time of 160-260ms is normal.

• Isovolumetric relaxation time: measure the time from the end of the

aortic outflow trace to the start of the mitral inflow trace. This

normally requires two different Doppler recordings (one of aortic

outflow and one of the mitral inflow) with timings taken relative to

a fixed point on the ECG. Normal range for 21-40yrs is 67 ± 8ms;

41-60yrs is 74 ± 7ms; over 60yrs is 87 ± 7ms.

• Valsalva manoeuvre: the mitral inflow pattern can be recorded again

with the patient performing a Valsalva. If there is pseudonormal

or reversible restrictive filling the trace will revert to an abnormal

relaxation pattern.

248

CHAPTER 4 Transthoracic chambers and vessels

Left atrial size

• Determine left atrial size by standard methods (b p.280). Increased

left atrial size implies raised left atrial pressure.

Pulmonary vein flow

• In the apical 4-chamber view ensure there is enough depth to see the

pulmonary vein inflow. The easiest vein to see (and best aligned for

Doppler) is the right upper pulmonary vein near the atrial septum.

Placement can be optimized with colour flow mapping to demonstrate

the pulmonary vein flow.

• Place the PW Doppler sample volume just inside the pulmonary vein

and record a spectral tracing. A good tracing confirms a satisfactory

position.

• The tracing will consist of 2 forward flow phases, systolic and diastolic,

followed by an atrial reversal (due to atrial systole). Normally the

systolic wave is dominant or equal to the diastolic wave.

• A prominent atrial reversal (>30cm/s peak velocity of the atrial wave

and >20-30ms longer duration of the atrial wave compared to the

duration of the A wave on the mitral inflow) is a specific but not very

sensitive marker of raised filling pressure. Blunting of the systolic flow

wave is a reliable marker of raised filling pressure in patients with

systolic dysfunction, but not normal function.

Tissue Doppler imaging

• In apical 4-chamber views place the PW tissue Doppler on the septal

or lateral annulus of the mitral valve (there is no clear consensus about

which is optimal). The tissue Doppler spectrum can be optimized by

decreasing the sample volume and optimizing gain settings (excessive

gain causes spectral broadening). Ensure it is aligned with the long axis

of the ventricle.

• The Doppler pattern should be the same as the mitral valve inflow

with an E wave and A wave (but below the baseline away from the

probe). Measure the peak velocity of both. They are usually referred

to as E’ and A’ (see Tables 4.4 and 4.5).

• E/E’ can also be calculated and relates to left atrial pressure. E/E’ <8

suggests normal left atrial pressure and E/E’ >15 suggests elevated left

atrial pressure.

• E/E’ is central to recent recommendations for the diagnosis of heart

failure with a normal ejection fraction (HFNEF) (see Fig. 4.32).

DIASTOLIC FUNCTION

249

Diastolic function: tips and measures

Transmitral flow categorization (see Figs. 4.16 and 4.31)

1. Impaired relaxation This is characterized by reduction of the peak

transmitral pressure gradient (hence lower E velocity and E/A ratio

[<1 in young, <0.5 in elderly]) and prolongation of the E deceleration

slope (>220ms in young, >280ms in elderly). Cardiac pacing, left bundle

branch block, and RV overload may provoke the same changes.

2. Pseudonormal filling As left atrial pressure increases with progressive

left ventricle disease, E velocity and deceleration time return to

normal. With exception of patients with more marked elevations

of filling pressure and low heart rate, who may show a mid-diastolic

(‘L’) wave, transmitral flow patterns cannot be distinguished from

normal without the performance of other steps. The first step is to

suspect the condition—‘normal’ transmitral flow in the setting of left

ventricle enlargement, hypertrophy, or systolic dysfunction is likely to

be pseudonormal. The second step is to assess left atrial size, followed

by estimation of filling pressure (as E/E’) and tissue Doppler of the mitral

annulus. Note that when left ventricle ejection fraction is preserved,

E deceleration time, the Valsalva response, blunting of the pulmonary

venous S wave (and S/D ratio), and flow propagation velocity may be

unreliable indicators of diastolic dysfunction.

3. Restrictive filling Continued elevation of filling pressure leads to

increased E velocity (increase in E/A ratio >2) and shorter E deceleration

time (<150ms). This finding is unusual with normal ejection fraction

(indicating a restrictive cardiomyopathy, e.g. amyloidosis), and is more

commonly associated with left ventricle dilatation and severe systolic

dysfunction. The presence of reversibility

(i.e. normalization with

Valsalva or after diuresis) is prognostically very important.

250

CHAPTER 4 Transthoracic chambers and vessels

Table 4.4 Age-adjusted normal cut-offs for selected diastolic

parameters

<40 years 40-60 years >60 years

E deceleration time (ms)

<220

140-250

140-275

Septal E’ velocity (cm/s)

Lateral E’ velocity (cm/s)

>11

>10

Table 4.5 Useful criteria for differentiating normal from pseudonormal

filling in adult subjects with normal left ventricular systolic function

Normal

Pseudo-normal

Lateral E’ velocity (depending on age)

>7-11

<7-11

Lateral E/E’

<10

>10

PV A velocity (cm/s)

<35

>35

PV A duration - transmitral

<30

>30

A duration (ms)

Valsalva manoeuvre

No significant

E/A <1 or

change in E/A

E/A decrease

ratio

by >50%

PV = pulmonary venous.

NORMAL

IMPAIRED

PSEUDO-

REVERSIBLE

FIXED

RELAXATION

NORMAL

RESTRICTIVE

MITRAL VALVE

0.75< E/A <1.5

E/A ≤ 0.75

0.75< E/A <1.5

E/A >1.5

INFLOW

Decel time >140ms

Decel time <140ms

Adur

PULMONARY

S>D

S<D or

VEIN FLOW

ARdur<Adur

ARdur >Adur+30ms

ARdur

TISSUE DOPPLER

E/E’ <10

E/E’ ≥10

MITRAL ANNULUS

Fig. 4.31 Doppler patterns for mitral valve, pulmonary vein, and mitral annulus to characterize diastolic function. The mitral inflow can be repeated with

a Valsalva manoeuvre and if there is pseudonormal filling the mitral inflow will change to an impaired relaxation pattern. Reversible restrictive describes a

restrictive pattern in which the mitral valve inflow also changes to an impaired relaxation pattern on Valsalva. Mitral: E = peak E wave velocity, A = peak

A wave velocity, Adur = duration of A wave. Tissue Doppler mitral annulus: E’ = peak velocity; A’ = peak velocity. Pulmonary vein flow: S = peak systolic

wave; D = peak diastolic flow; AR = peak atrial reversal flow; ARdur = duration of atrial reversal wave.

252

CHAPTER 4 Transthoracic chambers and vessels

HFNEF

Clinically, it is increasingly recognized that there is a group of patients

who require treatment for symptoms of heart failure (shortness of breath

etc.) but who have normal systolic cardiac function. These symptoms

appear to relate to underlying diastolic dysfunction and they are increas-

ingly referred to as patients with heart failure with a normal ejection frac-

tion (HFNEF). HFNEF could be a precursor of heart failure with reduced

ejection fraction. Guidelines have been established to help guide diagnosis

and treatment of this group of patients.

The diagnosis of HFNEF requires the following conditions to be fulfilled:

• Signs or symptoms of heart failure.

• Normal or mildly reduced LV systolic function (LVEF >50% and LV end

diastolic volume index <97mL/m2.

• Evidence of diastolic dysfunction.

Assessment for a diagnosis of HFNEF (Fig. 4.32)

• Left ventricular end-systolic and end-diastolic volumes should be

calculated from standard views to obtain a Simpson’s biplane or 3D

evaluation (b p.228).

• If left ventricular ejection fraction is >50% and the left ventricle is

not dilated (<97mL/m2) then proceed on to obtain an assessment

of diastolic function based on both tissue Doppler imaging of the

mitral annulus and transmitral inflow velocities by PW Doppler

(Fig. 4.30).

• Using these Doppler measures calculate the ratio of E/E’. This

correlates closely with left ventricular filling pressure and if E/E’ is

>15 then this is considered diagnostic for HFNEF. If E/E’ <8 then,

conversely, HFNEF is excluded.

• If E/E’ is between 8 and 15 then further echocardiographic evaluation is

required. Any of the following are considered to support a diagnosis of

HFNEF:

• E/A <0.5 and deceleration time >280ms (age >50 years).

• LA indexed volume >40mL/m2.

• LV mass index >122g/m2 (female) or >149g/m2 (male).

• Duration of reverse pulmonary vein atrial flow—duration of mitral

valve atrial wave flow >30ms.

HFNEF

253

How to diagnose HFNEF

Symptoms or signs of heart failure

Normal or mildly reduced left ventricular systolic function

LVEF > 50%

and

LVEDVI < 97 mL/m²

Evidence of abnormal LV relaxation, filling

diastolic distensibility, and diastolic stiffness

Invasive Haemodynamic

Biomarkers

measurements

E/E′ > 15

15 > E/E′ > 8

NT-proBNP

mPCW > 12 mmHg

> 220pg/mL

LVEDP > 16 mmHg

BNP > 200pg/mL

τ > 48 ms

b > 0.27

Biomarkers

Echo - Bloodflow Doppler

NT-proBNP

E/A>50yr < 0.5 and

E/E′ > 8

> 220pg/mL

^DT>50yr >^{280 ms}

BNP > 200pg/mL

Ard-Ad > 30 ms

LAVI > 40 mL/m²

LVMI > 122 g/m² (5):

149 g/m (4)

Atrial fibrillation

HFNEF

Fig. 4.32 Diagnostic flowchart on ‘How to diagnose HFNEF’ in a patient suspected

of HFNEF. LVEDVI, left ventricular end-diastolic volume index; mPCW, mean

pulmonary capillary wedge pressure; LVEDP, left ventricular end-diastolic pressure;

t, time constant of left ventricular relaxation; b, constant of left ventricular chamber

stiffness; TD, tissue Doppler; E, early mitral valve flow velocity; E0, early TD

lengthening velocity; NT-proBNP, N-terminal-pro brain natriuretic peptide; BNP,

brain natriuretic peptide; E/A, ratio of early (E) to late (A) mitral valve flow velocity;

DT, deceleration time; LVMI, left ventricular mass index; LAVI, left atrial volume

index; Ard, duration of reverse pulmonary vein atrial systole flow; Ad, duration of

mitral valve atrial wave flow. Paulus WJ et al. Eur Heart J 2007. 28(20):2359-550.

254

CHAPTER 4 Transthoracic chambers and vessels

Left ventricular synchrony

The current selection criteria for cardiac resynchronization therapy

include NYHA class III or IV heart failure symptoms and left ventricle

ejection fraction <35% on maximal medical therapy, in the setting of a

widened QRS (the relevant QRS width varies between trials, but usually

is >120ms (usually left bundle branch block)). Despite using these criteria

20-30% do not respond and it may be that others with heart failure would

benefit.

Markers of dyssynchrony (Fig. 4.33)

Echocardiographic assessment of synchrony can be used for patient

selection, pacing site selection, or both. Synchrony can be assessed be-

tween right ventricle and left ventricle (interventricular dyssynchrony—

electromechanical delay in right ventricular outflow tract and left ventricular

outflow tract) or within the left ventricle (intraventricular dyssynchrony—

M-mode, tissue Doppler, strain, 3D). There are few comparisons between

the markers and centres often offer a ‘menu’ of measurements. A list

follows, with findings that would suggest dyssynchrony:

• M-mode septum to posterior delay >130ms.

• Inter-ventricular delay >40ms.

• Systolic strain (% delayed contraction >30).

• Septal to posterior wall delay >65ms by tissue Doppler imaging.

• Dyssynchrony index >32.6ms.

• Parametric markers: tissue strain index, tissue tracking.

Interventricular dyssynchrony

Interventricular dyssynchrony is the difference in time between onset of

pulmonary flow and onset of aortic flow ( 40ms suggests dyssynchrony).

Because separate views are needed for each measurement the onset of

flow in each view is timed relative to the ECG trace.

• Obtain a parasternal short axis view (aortic valve level). Record a PW

Doppler tracing through the pulmonary valve. Ensure there is a surface

ECG recording.

• In an apical 4-chamber view place a PW Doppler in the outflow tract

and record a tracing. Ensure there is a surface ECG trace.

• Measure the distance from the start of the QRS to the start of the

pulmonary valve flow on the first view then measure the distance

from the start of the QRS to the start of the aortic valve flow on the

second view. The difference is the interventricular delay.

Intraventricular dyssynchrony (septal vs. lateral wall)

Intraventricular dyssynchrony is the delay between the septal and poste-

rior wall peak contraction ( 130ms suggests dyssynchrony), i.e. the delay

between the opposite walls of the left ventricle being fully contracted.

• In a parasternal long axis view drop the M-mode cursor perpendicular

to the septal and posterior wall. On the tracing identify the peak of

septal and posterior wall systolic motion. Measure the time difference

between the 2 walls and this is the intraventricular delay.

256

CHAPTER 4 Transthoracic chambers and vessels

Tissue Doppler measures

Differences in movement of the mid and basal segments of each wall of

the left ventricle can be assessed by tissue Doppler imaging to provide

some impression of the coordination of the ventricle. The assessment can

be based on 8 measures from apical 4- and 2-chamber views, or 12 meas-

ures, which include measures in the apical 3-chamber view (Fig. 4.34).

• In apical 4-chamber place the tissue Doppler sample volume on each

side of the mitral valve annulus and in the mid segments of the septum

and lateral wall. Record tracings in each position.

• Repeat the process in the apical 2-chamber view on each side of the

annulus and the mid segments of the inferior and anterior walls.

• This can then be repeated in the apical 3-chamber view in all 4 basal

and mid segments.

• Measure the time from the start of the QRS to the systolic phase of

motion on each tracing.

• The standard deviation of the 8 (or 12) measures provides a global

index of dyssynchrony (>33ms suggests dyssynchrony).

• An alternative measure is the delay between the basal septum and

basal lateral wall in the apical 4-chamber view (>60ms suggests

dyssynchrony).

• Finally if any of the 8 (or 12) measures are >100ms different then this

suggests dyssynchrony.

Use in follow-up: how to define success?

The most widely used markers include clinical improvement (formalized

as improvement in heart failure class or quality of life score) and improved

exercise capacity (e.g. lengthening of a 6-minute walk). Echocardiographic

markers include 15% decrease in left ventricle volumes, 5% increase

in ejection fraction, any decrease in left ventricle mass, or a decrease in

mitral regurgitation severity.

Unresolved issues

Current guidelines for CRT therapy do not include dysynchrony meas-

urements. There are controversial studies on the value of routine syn-

chrony studies for decision on CRT treatment. A number of potential

contributions from echocardiography remain unresolved:

• What is the optimal synchrony marker to predict recovery?

• Predicting response to CRT using 2D echocardiography has been

seen with varying degrees of success.

• Should echocardiography be used to assess ischaemia/viability?

• Is guidance regarding optimal pacing site useful?

• Should echocardiography be used to make adjustments to pacing

parameters over time as cardiac function varies?

258

CHAPTER 4 Transthoracic chambers and vessels

3D for assessment of dyssynchrony? (Fig. 4.35)

• Real-time 3D echocardiography has been used to quantify global LV

mechanical dyssynchrony in patients with and without prolonged

QRS duration.

• Using real-time 3D echocardiography, data sets for global and

segmental LV volumes can be processed to analyse the time-volume

relationship during the cardiac cycle.

• From 3D LV acquisition, a series of volume curves can be obtained

to show the variation of segmental volume during the cardiac cycle.

In a synchronous ventricle, the individual segmental volume curves

should reach their minimum volumes at a similar time at end systole.

With a dyssynchronous LV, the segmental volume traces vary with

respect to time.

• A systolic dyssynchrony index (SDI) has been proposed which

can be used to identify chronic heart failure patients who may not

otherwise be considered for CRT. Here, the SDI is defined as the

standard deviation of the time taken to reach minimal regional

volume using a 16-segment model and expressed as a percentage

of the cardiac cycle. It has been shown that clinical responders to

CRT had larger SDI at baseline versus non-responders and that an

SDI >6.4% had a sensitivity of 88% and a specificity of 86% to predict

acute volumetric response to CRT.

Advantages and disadvantages of 3D for dyssynchrony

The use of real-time 3D imaging has advantages over 2D echocardiography:

• There is simultaneous acquisition of all LV segments during the same

cardiac cycles.

• All LV segments are recorded simultaneously and thus avoid

problems with heart rate variability which may be seen in 2D

echocardiography.

The use of real-time 3D imaging has the disadvantages:

• The image quality of real time 3D echocardiography is lower than

that for 2D echocardiography with lower temporal resolution than

2D tissue Doppler imaging.

• Stitching artefacts may be more prevalent in the population of

patients being assessed due to breath-holding problems and also

rhythm disturbances.

260

CHAPTER 4 Transthoracic chambers and vessels

Optimization

Optimization procedures often do not lead to clinical improvement but

two pacing parameters can be altered to test for benefit. Delay between

pacing atrium and ventricle (AV delay) and delay between pacing left and

right ventricle (VV delay).

Assessment

Start

Ensure you have the appropriate pacemaker programmer and a technician.

Start by collecting the standard baseline dyssynchrony measures (b p.254)

and record the current programmed AV and VV delay.

AV delay (Fig. 4.36)

The aim is to choose the shortest AV delay that still allows complete

ventricular filling. There are 2 approaches. Both use apical 4-chamber view

with a PW Doppler profile of mitral valve inflow.

Iterative method

• Program a short AV delay (e.g. 50ms) on the pacemaker. Look at the

A-wave and decrease the delay in 20ms steps until the A-wave starts

to be truncated. Then gradually extend the delay by 10ms steps until

the A-wave is just complete (Fig. 4.36).

Ritter method

• Program a short AV delay (e.g. short delay = 50ms) and measure

distance from start of QRS to end of A wave (QAshort).

• Program a long AV delay (e.g. long delay = 150ms) and measure

distance from start of QRS to end of A wave (QA long).

• Calculate optimal delay as = long delay + QAlong - QAshort.

VV delay (Fig. 4.37)

In an apical 5-chamber view place PW Doppler in left ventricular outflow

tract. Keep it in the same position throughout the study.

• Start the VV delay with left ventricle paced 80ms before the right.

• Record a spectral profile and annotate with the VV delay.

• Calculate the vti by tracing the spectral profile.

• Reduce the delay by 20ms to 60ms and record another vti.

• Repeat, reducing delay by 20ms until there is no delay (0ms).

Then start pacing right ventricle first, increasing in 20ms increments

up to 80ms.

• Also, try left and right ventricle pacing alone.

• Look at results and identify parameter with maximal vti. There should

be a graded pattern away from the optimal delay. Choose this as the

new VV delay.

• If decision is to pace right ventricle first AV delay should be reset.

new optimal AV delay = previous optimal AV delay − VV delay.

Finish

Program new AV and VV delay. Finish study with full re-evaluation of

synchrony to ensure improvement following reprogramming.

262

CHAPTER 4 Transthoracic chambers and vessels

Right ventricle

Normal anatomy

The right ventricle is made up of inflow (sinus), apical trabecular, and

outflow (conus) regions though there is no clear demarcation between

each. Towards the apex a muscular moderator band connects the free wall

and septum. The combination of a thin free wall and thick septum leads

to an irregular crescent shape when viewed in short axis with asymmetric

contraction. The right ventricle maintains blood flow from the venous

system to the pulmonary vasculature and from there to the left atrium

and left ventricle. Size and function can therefore be affected by pulmo-

nary problems (e.g. pulmonary hypertension, embolism), left-sided heart

disease (e.g. left ventricle failure, mitral valve disease), and right ventricular

disorders (e.g. infarction, dysplasia). Septal defects have important effects

on right ventricular function because the right heart is exposed to systemic

pressures.

Normal findings

Views

• Key views are: parasternal long axis; parasternal right ventricular inflow

and outflow; parasternal short axis (aortic valve, mitral valve and mid-

papillary levels); apical 4- and 3-chamber; subcostal (Fig. 4.38).

Findings

• Parasternal long axis: right ventricle nearest probe. View can be used

for M-mode measures of the proximal RVOT.

• Parasternal right ventricular inflow and outflow: these give excellent

views of tricuspid and pulmonary valves. TR jet velocity can be

measured if there is good alignment.

• Parasternal short axis (aortic valve, mitral valve, and mid-papillary

levels): right ventricle wraps around the left ventricle and therefore

can be scanned through at multiple levels (as for the left ventricle).

At the aortic valve it can be seen with both tricuspid and pulmonary

valves and Doppler measures can be performed. As the plane moves

towards the apex, the right ventricle is seen as a crescent to the left

of the left ventricle. These views can give an impression of size and, in

combination with septal appearance, of right ventricular pressure.

• Apical views: this can be used to assess function based on tricuspid

annulus movement. Cranial tilt of probe may demonstrate right

ventricular outflow. Visualization of TR jet is improved by medial and

cranial displacement of the probe.

• Subcostal view: right ventricle nearest probe with ventricular

septum horizontal. Best view for septal defects (colour flow) as well

as measuring wall thickness. A short axis view of basal right ventricle

can be achieved in certain patients, particularly if thin. Doppler

interrogation of outflow and main pulmonary artery can

be undertaken.

264

CHAPTER 4 Transthoracic chambers and vessels

Right ventricular size

The right ventricle has a complex shape so assessment of size is often

performed qualitatively. However, the right ventricle has significant clinical

relevance and a more thorough quantitative assessment is now warranted.

This task has been aided by recent guidelines which have provided guid-

ance on quantification and normal values.

Assessment

Assess the right ventricle in several views. If it does not appear normal

comment on cavity size, as well as wall thickness, outflow tract size, and

right atrial area.

2D measures of size

Right ventricular cavity size

• The apical 4-chamber view should be focused to maximize the size

of the RV such that it transects the acute margin of the RV while

keeping the LV apex in view. The latter is key since it is easy artificially

to make the RV form the apex and be bigger than the LV.

• A useful rule of thumb is that the normal RV should be two-thirds the

size of the LV. However this relies on the LV being normal sized itself.

Appearances of the cardiac apex can be instructive: with moderate

amounts of dilatation, the acute angle formed by the RV free wall and

septum increases. In severe RV dilatation, the RV apex can dominate

over the left.

• Overall, it is more helpful to assess RV size quantitatively using the

diameter at the tricuspid annulus and mid cavity diameter which should

be less than 4.2cm and 3.5cm respectively.

• If so this can be reported as apex forming.

• The RVOT can be measured in the left parasternal (and subcostal

views if necessary). The proximal RVOT is seen in the PLAX and

PSAX at the level of the aortic valve (RVOT1) where a value >33mm

is abnormal, but it is preferred to take the distal RVOT (RVOT2)

where the PV and infundibulum meet. The RVOT is dilated here if

>27mm. (See Fig. 4.39 and Table 4.6.)

Right atrial area can be measured from planimetry in the apical 4-chamber

considered to reflect RA enlargement.

266

CHAPTER 4 Transthoracic chambers and vessels

3D measures of size

Analysis of 3D right ventricular views is currently possible with a commer-

cially available software package (4D-RV Function, TomTec, Germany). Only

patients with very good image quality should be considered for 3D echocar-

diography of the right heart. Also, for accurate assessment there should

be no arrhythmia, and breath-holding capacity should be good. Following

initial acquisition of the 3D dataset, cut planes are reviewed in the short axis

view (in order to outline the tricuspid valve in the optimal position), apical

4-chamber plane (to outline the apex) and the coronal plane (to outline the

RVOT). The right ventricular volumes are calculated by summing the areas

for each slice through the complete volume data set (Table 4.7).

Acquisition of 3D volume for assessment of RV and RA volumes

• Position the probe at the apex in the same position as for acquisition

of 2D 4 chamber views.

• The biplane preview (Fig. 4.40) screen is used so that the 4- and

2- chamber views can be seen simultaneously to help avoid

foreshortening.

• Sometimes the probe will need to be tilted anteriorly towards the

RVOT.

• Depth, gain, and TGC are adjusted in 2D imaging in order to achieve

the best possible endocardial definition.

• For full volume datasets maximize the number of subvolumes (beats)

used to generate the 3D image according to patient breath-holding

capabilities. The greater the number of subvolumes, the greater the

temporal resolution.

• Acquire 2D or more 3D datasets as artefacts are common and then

inspect the dataset.

• Use short axis planes to make sure there are no stitching artefacts.

Use the cropping tool to ensure there is good endocardial delineation

and that the right ventricular outflow tract is included in the dataset.

• If the listed criteria are not adequate delete and reacquire.

Table 4.7 Normal values for 3D RV volumes and ejection fraction

LRV (95% CI) Mean (95% CI) URV (95% CI)

3D RV EF (%)

44 (39-49)

57 (53-61)

69 (65-74)

3D RV EDV indexed (mL/m2) 40 (28-52)

65 (54-76)

89 (77-101)

3D RV ESV indexed (mL/m2) 12 (1-23)

28 (18-38)

45 (34-56)

CI, confidence interval; EF, ejection fraction; EDV, end-diastolic volume; ESV, end-systolic

volume; LRV, lower reference value; URV, upper reference value.

RIGHT VENTRICULAR SIZE

267

Fig. 4.40 Acquisition of full volume RV 3D dataset showing initial biplane view

used to optimize the RV and to avoid foreshortening. 4-chamber view (left) and

2-chamber view (right).

Fig. 4.41 Image orientation and setting of anatomical landmarks. The initial 3D

dataset is displayed as three 2D images: 4-chamber (top left), 2-chamber (top

right), and 2 short axis (sagittal) views (bottom). Moving the blue dashed cursor up

and down the ventricle will allow the coronal view to be altered accordingly. The

program prompts the operator to mark the centre of the tricuspid valve (blue dot),

centre of the mitral valve (red dot) and centre of the LV apex (green dot). Once

this has been completed, then RV contouring can be performed. See W Video 4.13.

268

CHAPTER 4 Transthoracic chambers and vessels

Processing the dataset

Image orientation and setting of anatomical landmarks

• TomTec (Germany) allows post processing of full volume 3D right

ventricular datasets. Initially the operator is prompted to select the

orientation from which the image was acquired (apical-lateral, apical-

medial or subcostal).

• Play the dataset initially and confirm that the chosen end-systolic and

end-diastolic frames are correct or adjust if needed.

• The initial display shows the 3D volume as a sequence of three 2D

slices: the apical window, the 2-chamber window (coronal view), and

the short axis window (sagittal view).

• When the cropping mode is activated these views usually are displayed

but often have to be adjusted in order to obtain the right ventricle in

full length, to include RVOT and to get the sagittal mid right ventricle

view around 90° angulated to the apical 4-chamber view.

• The postprocessing system will prompt you to identify certain

anatomical landmarks on the sagittal (e.g. centre of tricuspid valve,

centre of mitral valve, and the left ventricular apex), Fig. 4.41. The

landmarks are obtained by slicing the apical view using the slice prompt

(see Fig. 4.42 blue dashed line). When the centre of the tricuspid valve

is located the position is marked on the sagittal view (see Fig. 4.41,

blue dot). The centre of the mitral valve is then marked (see Fig. 4.41,

red dot). Finally the horizontal cutting plane (yellow dashed line) is

moved so that the sagittal view is cutting the left ventricular apex and

again this is marked on the sagittal view (see Fig. 4.41, green dot).

RV contouring

• The initial contours are then set in the apical 4-chamber view; sagittal

and coronal cut planes in end-systole and end-diastole, see Fig. 4.42.

• During contouring of the sagittal and coronal planes, the program

helps the operator to delineate the endocardial border by showing

circular targets which the contour should pass through (see Fig. 4.42).

• Trabeculations are included in the endocardial rim, but the apical

component of the RV moderator band is excluded from the cavity.

The software then will calculate the contours in the other slices and

frames.

• After the 3 planes have been contoured, check the calculated contours

with reference to the true anatomical structure of the right ventricle

by slicing through the right ventricular cavity and making corrections if

major deviations are observed.

• The TomTec programme will then estimate the right ventricular end-

diastolic, end-systolic, and stroke volumes as well as calculating the

right ventricular ejection fraction.

• The right ventricular motion can be reviewed in a 3D model and

rotated to be seen from different angles (Fig. 4.43).

• The right ventricular motion can also be viewed, for instance with a

static wire frame, see Fig. 4.43.

270

CHAPTER 4 Transthoracic chambers and vessels

Right ventricular wall thickness

This can be assessed at end-diastole using M-mode imaging in the parasternal

long axis view, or more consistently from the subcostal view (Fig. 4.44).

Normal is <0.5 cm.

• In the subcostal view use a clear 2D image frozen in end-diastole (or

perpendicular M-mode trace). Measure from edge-to-edge of the free

wall at the level of the of the tip of the anterior tricuspid valve leaflet.

• In the parasternal view use a 2D image or M-mode trace with cursor

perpendicular to the ventricle wall at the mitral valve tip level.

• In either view take care not to include epicardial fat, coarse

trabeculations, or papillary muscles in the measurement.

272

CHAPTER 4 Transthoracic chambers and vessels

Right ventricular function

• Although it can be evaluated qualitatively by studying the movement of

the right ventricle free wall and assigning a label of normal or impaired

to right ventricular systolic function, quantitation of right ventricular

systolic function is now recommended.

• A number of measures of right ventricular systolic function have

evolved whose purpose is to sidestep the difficulties of using

volumetric techniques established in the left ventricle for the

geometrically complex right ventricle.

• The number of surrogates for right ventricular systolic function is a

reminder that no single index predominates. More recently, quantifying

right ventricular systolic function using volumetric techniques has been

simplified by advances in 3D imaging acquisition and analysis.

Assessment

• Assess right ventricular function from the apical 4-chamber view.

• Confirm your impression in parasternal and subcostal views.

• Concentrate on movement of the tricuspid annulus to get an overall

impression of function.

• Support this by looking at regional wall motion abnormalities and

thickening along the free wall to the apex, note whether areas are

normal, akinetic or dyskinetic (use same criteria as left ventricle regional

assessment, b p.234).

When assessing regional wall motion abnormalities, bear in mind that the

right ventricular free wall is predominantly supplied by the right coronary

artery and that the septum, apex, and, in some patients, the distal free

wall is supplied by the left anterior descending artery. Where possible,

use the 4 methods described in this section to quantify right ventricular

systolic function:

Myocardial Performance Index (MPI) or TEI index

• Considered a cumulative measure of right ventricular systolic and

diastolic dysfunction.

• It is calculated by dividing the isolvolumic time by ejection time.

• These measures can be derived using pulsed Doppler. The ejection

time is derived from the spectral trace in the RVOT and the

isovolumic time from the pulsed Doppler of inflow across the tricuspid

valve. Ensure heart rates are similar when each pulsed Doppler

measure is recorded as variation in cardiac cycle length will make the

measures inaccurate. This means it is particularly unreliable in atrial

fibrillation.

• Alternatively, both indices can be derived at the same time from the

TDI trace of the tricuspid annulus (Fig. 4.45).

• A value >0.40 for the pulsed Doppler method and 0.55 for the TDI are

abnormal.

274

CHAPTER 4 Transthoracic chambers and vessels

Tricuspid annular plane systolic excursion (TAPSE)

In the normal right ventricle, the lateral side of the tricuspid annulus moves

towards the apex during systole reflecting right ventricular longitudinal

function. TAPSE is a way of measuring how much it moves.

• Obtain an apical 4-chamber view.

• Place the M-mode cursor through the lateral annulus of the tricuspid

valve and record a trace (Fig. 4.46).

• Measure the maximum excursion.

• A value <16mm indicates right ventricular systolic dysfunction.

Although a simple, reproducible measure it relies on the assumption that

longitudinal motion is a surrogate for right ventricular systolic function as

a whole.

Peak systolic velocity of right ventricular basal free wall TDI (Fig. 4.45)

Similar to TAPSE this measure assesses movement of the right ventricular

free wall. However, instead of looking at the distance the tricuspid an-

nulus moves it uses tissue Doppler imaging to measure how quickly the

annulus moves.

• Obtain an apical 4-chamber view.

• Place the pulse wave TDI cursor either on the lateral edge of the

tricuspid annulus or basal segment of the right ventricular free wall

close to the annulus (normally well seen with transthoracic echo).

• Obtain a tissue Doppler trace and measure the maximal systolic

velocity of the basal right ventricular free wall. This is referred to as S’.

• S’ velocity <10cm/s reflects right ventricular systolic dysfunction.

Ejection fraction and fractional area change (FAC)

Right ventricular ejection fraction is difficult to measure on 2D because of

complex geometry but, if available, 3D volume acquisitions can be post-

processed using dedicated software to calculate volumes over the cardiac

cycle and derive an ejection fraction.

On 2D imaging fractional area change can be assessed from an apical

4-chamber view (Fig. 4.47). To perform this measure

• Obtain a clear apical 4-chamber view.

• Identify the end-diastolic frame (largest ventricle). Trace around

the endocardial border being careful to exclude right ventricular

trabeculae and obtain an area.

• Identify the end-systolic frame and repeat the process to obtain the

end-systolic area.

• The difference between the 2 measures can be reported as a

percentage relative to the end-diastolic area.

• A 2D fractional area change of <35% indicates right ventricular systolic

dysfunction.

276

CHAPTER 4 Transthoracic chambers and vessels

Right ventricular overload

Identifying volume or pressure overload in the right ventricle can aid

clinical assessment of right heart function. Although often considered

together they usually represent 2 different initial pathologies. Right volume

overload suggests a left-to-right shunt or right-sided valvular regurgitation.

Pressure overload suggests pulmonary hypertension or pulmonary stenosis.

Pressure overload can develop from volume overload, and occasionally vice

versa, in which cases features of both will be present.

Assessment

The key points to look at when evaluating the 2 situations are:

• What happens to right ventricle size and thickness (b pp.264-71)?

• Volume overload leads to increased cavity size and pressure overload

leads to increased wall thickness. However, one can lead to the

other and the two findings will coexist.

• How does the interventricular septum behave during the cardiac cycle?

• Simply, volume overload is related to a flattened septum in diastole

whereas pressure overload is associated with a flattened septum in

both diastole and systole.

Assess right ventricular systolic pressure (b p.162) to help support your

impression of right ventricle pressure or volume overload.

Volume overload (Fig. 4.48)

• Obtain a clear parasternal short axis (mid papillary level) view.

• Ventricle size and wall thickness: in volume overload the right ventricle

should be dilated (the same size or bigger than the left ventricle) so

comment on size. In chronic overload the right ventricle may start to

hypertrophy but this will be eccentric as there will still be dilatation.

• Septum: the septum will flatten in diastole due to the large right

ventricular volume and create a D-shaped ventricle (as volume

overload worsens it will start to bow into the left ventricle). But then

in systole the left ventricle reverts to a circular shape. This creates

abnormal septal motion towards the left ventricle in diastole and

towards the right ventricle in systole.

Pressure overload

• Use the same parasternal short axis (mid papillary level) view.

• Ventricle size and wall thickness: in chronic pressure overload the right

ventricle free wall thickens (normally half left ventricle thickness) but

the cavity will remain the same until the right ventricle starts to fail.

• Septum: as pressure increases the septum will flatten out towards the

left ventricle through both diastole and systole. With chronic pressure

overload and increase in wall thickness the right ventricle will start

to behave more like a left ventricle, the septum will bow into the left

ventricle and contract towards the right ventricle during systole. This

also creates paradoxical septal motion (but for a different reason from

volume overload).

278

CHAPTER 4 Transthoracic chambers and vessels

Left atrium

Normal anatomy

The left atrium receives blood from the 4 pulmonary veins. It acts as a

reservoir and as a conduit to transport blood to the left ventricle. It has

contractile function and atrial systole contributes approximately 25% of left

ventricle filling. Morphologically the atrium can be considered as having a

body and an appendage. The common anatomical variations related to

the atrium are those associated with the atrial septum, such as aneurysm,

patent foramen ovale, atrial septal defect, or lipomatous hypertrophy. Rare

anatomic variants can occur within the atrium such as cor triatum, in which

the left atrium is separated into a superior and an inferior chamber.

Normal findings

Views

• The key views for the left atrium are: parasternal long axis, and apical

4- and 2-chamber (Fig. 4.49). The apical views are the most useful to

assess left atrial volume and left atrial haemodynamics.

• The parasternal short axis (aortic valve level) includes the left atrium

and can be useful to look at the septum. The subcostal view aligns the

left and right atrium perpendicular to the probe so can be useful for

Doppler assessment of the septum.

Findings

• Parasternal long axis: the left atrium lies below the aortic root and the

view is used for simple linear measures of left atrial size.

• Parasternal short axis (aortic valve level): the left atrium lies below the

aortic valve. The interatrial septum is seen on the left and the left atrial

appendage can occasionally be seen on the right.

• Apical 4- and 2-chamber: the left atrium lies at the bottom of the

images and the views allow assessment of left atrial volume. The

septum can also be studied. However, it lies vertically in the image and

it is difficult to identify defects or do Doppler measures. Pulmonary

veins are seen at the back of the atrium in the apical 4-chamber

(particularly the right upper vein that lies by the septum). In the apical

2-chamber the left atrial appendage can sometimes be seen pointing

out to the right. Generally, the left atrial appendage is only rarely

visualized by transthoracic imaging.

• Subcostal view: the septum lies horizontal in the image and this is the

best view to look for septal defects with colour flow and Doppler.

280

CHAPTER 4 Transthoracic chambers and vessels

Left atrial size

Left atrial enlargement is of clinical importance as it is associated with

adverse cardiovascular outcome from a range of pathologies including

myocardial infarction, stroke, dilated cardiomyopathy, and diastolic left

ventricular failure with increased filling pressure. Atrial enlargement is also

associated with atrial fibrillation.

Assessment

Preferred assessment is with volumes measured in apical views. Historically

linear measures in parasternal views are quoted. This is the anteroposterior

diameter. If the atrium has enlarged along the long axis of the heart this may

be missed with single anteroposterior linear measures.

Volumetric measures

Volume measures use the same principles and equations as for left ventricle

volume assessment (b p.196). The left atrium can be modelled with the

area-length formula, Simpson’s method (that cuts the atrium into a series

of disks and adds up the volumes of each disk), and the ellipsoid method.

All calculations are usually done automatically by the machine software

but require measurement of atrial length and diameters or planimetry

of cross-sectional area. If measures are done in the 4-chamber view it is

assumed that the atrium is spherical. Use of both 4- and 2-chamber views

allow 3D assessment.

• Obtain a clear apical 4-chamber view with enough depth to include the

whole of the left atrium.

• Record a loop and scroll through to identify end-systole.

• Planimeter around left atrium excluding the junction of the pulmonary

veins and left atrial appendage (if visible). Record the area.

• Measure the length from back of the left atrium to the midpoint of a

line across the mitral annulus (Fig. 4.51).

• Repeat the process in the apical 2-chamber view.

• Use the shorter of the 2 lengths as the measure of atrial length.

• The machine will calculate volumes by Simpson’s method.

• The area length formula for left atrial volume is calculated as:

area in

2-chamber

3×

× atrial length

• The ellipsoid formula is:

2)×(

2)× apical view diameter 2)

Linear measures

• In a parasternal long axis view, record a 2D loop and identify end-

systole. Measure perpendicularly across the atrium from edge-to-edge.

• Alternatively, drop the M-mode cursor across the atrium at the level

of the aortic valve tips, perpendicular to the walls. Measure left atrial

size at end-systole (maximal size) (Fig 4.50).

LEFT AND RIGHT ATRIA: NORMAL RANGES

283

Left and right atria: normal ranges (Table 4.8)

Table 4.8 Parameters to assess left and right atria

WOMEN

NORMAL

MILD MODERATE

SEVERE

Atrial dimension

LA diameter, cm

2.7-3.8

3.9-4.2 4.3-4.6

>4.6

LA diameter, BSA, cm/m2

1.5-2.3

2.4-2.6 2.7-2.9

>2.9

RA minor axis, cm

2.9-4.5

4.6-4.9 5.0-5.4

>5.4

RA minor axis/BSA, cm/m2

1.7-2.5

2.6-2.8 2.9-3.1

>3.1

Atrial area

LA area, cm2

<20

20-30 31-40

>40

Atrial volume

LA volume, mL

22-52

53-62 63-72

>72

LA volume/BSA, mL/m2

<29

29-33 34-39

>39

MEN

NORMAL

MILD MODERATE

SEVERE

Atrial dimension

LA diameter, cm

3.0-4.0

4.1-4.6 4.7-5.2

>5.2

LA diameter, BSA, cm/m2

1.5-2.3

2.4-2.6 2.7-2.9

>2.9

RA minor axis, cm

2.9-4.5

4.6-4.9 5.0-5.4

>5.4

RA minor axis/BSA, cm/m2

1.7-2.5

2.6-2.8 2.9-3.1

>3.1

Atrial area

LA area, cm²

<20

20-30 31-40

>40

Atrial volume

LA volume, mL

18-58

59-68 69-78

>78

LA volume/BSA, mL/m2

<29

29-33 34-39

>39

BSA, Body surface area.

Bold rows identify best validated measures.

284

CHAPTER 4 Transthoracic chambers and vessels

Right atrium

The right atrium acts as reservoir for blood from the coronary sinus, and

inferior and superior vena cava. It has some unique anatomical features

that can be mistaken for pathology. These include the Eustachian valve,

which in utero directs blood from the inferior vena cava through the

foramen ovale but becomes redundant after birth. If it does not regress

it is seen attached to the right atrial wall between the inferior vena cava

and border of the fossa ovalis. A Chiari network is a remnant from the

embryological stage before the Eustachian valve forms and is a thin mem-

brane, typically fenestrated, near the orifice of the inferior vena cava and

extending further across the right atrium than the Eustachian valve.

Normal views and findings

• The right atrium can be seen in a modified right ventricle inflow view

and parasternal short axis view (aortic valve level) (Fig. 4.52).

• The apical 4-chamber view is useful for volume measurements and

Doppler interrogation of tricuspid valve inflow.

• The subcostal view often provides excellent views of the right atrium

and right atrial inflow from the inferior vena cava.

Right atrial size

Techniques to measure right atrial size are borrowed from those for the

left atrium but assessment is less clinically relevant. Right atrial size meas-

urements are most often used in assessment of right ventricular systolic

pressure (b p.264). There is little research or clinical data so normal

ranges are fairly simplistic without reference to sex or body size.

Qualitative measures

• The simplest assessment is to compare the left and right atria in an

apical 4-chamber view (Fig. 4.53). If the right atrium appears larger than

the left it is dilated.

Quantitative measures

• Minor axis is a simple linear measure. On an apical 4-chamber view

measure across the middle of the atrium from lateral wall to septum.

Ranges are in Table 4.8.

• Area can be reported. Trace around the right atrium joining the lateral

and septal sides of the tricuspid annulus with a straight line.

• A volume can be calculated using the area length equation (b p.196)

with measures from an apical 4-chamber view. Right atrial length is

required and can be measured from the back of the atrium to the

middle of the annulus.

286

CHAPTER 4 Transthoracic chambers and vessels

Interatrial septum

Normal anatomy

The atrial septum divides the left and right atrium. Embryologically it develops

as two distinct sheets, the primum and secundum septum. In utero the

septum, specifically the foramen ovale, acts as a portal for blood to pass

from the inferior vena cava, directed by the Eustachian valve, to the left side

of the heart, bypassing the lungs. After birth the foramen closes. In around

80% of people it seals but remains evident as a depression in the septum

called the fossa ovalis. In 20% it remains as a potential communication

between right and left heart.

Normal findings

Views

The atrial septum is best assessed in a subcostal view (Fig. 4.54). This is the

only view that has the septum perpendicular to the probe and therefore

aligns the septum for Doppler or colour flow assessment. The atrium can

also be assessed in the parasternal short axis (aortic valve level) and apical

4-chamber view. Agitated saline contrast can be used to investigate the

possibility of a patent foramen ovale.

Findings

• Parasternal short axis (aortic valve level): the septum lies in the far

field extending from the aortic ring (usually at the bottom left) with

the left atrium on the right and right atrium on the left.

• Apical 4-chamber: the septum can be seen lying between the atria in

the far field. Because it is in line with the probe there may be areas

of ultrasound dropout that can be confused for defects. Colour flow

mapping in this view can be tried.

• Subcostal view: the right atrium lies nearest the probe and the septum

lies across the screen. This view can be used for colour flow mapping

and Doppler alignment through the septum.

288

CHAPTER 4 Transthoracic chambers and vessels

Atrial septal defects

Atrial septal defects are the commonest congenital heart defect. Although

they can occur on their own they are frequently associated with other

defects and a full echocardiographic assessment should be performed. They

can also be iatrogenic (e.g. after cardiac surgery and transseptal puncture)

or accidental (e.g. after pacing). There are 4 types of congenital defect:

• Secundum atrial septal defect (65%)—fossa ovalis/central septum.

• Primum atrial septal defect (15%)—more muscular septum by valves.

• Sinus venosus defect (10%)—near the superior vena cava/posterior

and superior septum.

• Coronary sinus defects are much rarer.

Assessment

Initial assessment should be with 2D imaging, followed by colour flow map-

ping to study direction of flow (Fig. 4.55) and then Doppler to quantify the

size of the shunt. Where suspicion of a defect remains high, a contrast study

can be performed with Valsalva to identify a left-to-right shunt (b p.572).

Full assessment may require a transoesophageal study (see Chapters 5 and 7).

2D and colour flow mapping

Study the septum in all the standard views and look for gaps in the septum.

To avoid overcalling septal dropout the defect should be apparent in differ-

ent planes. There may be indirect evidence of a problem that prompts more

careful study, in particular: right atrial and right ventricular enlargement

without other cause; an abnormally directed colour flow jet in the right

atrium on colour flow mapping; abnormal septal motion or an aneurysmal

septum. Comment on:

• The position of the defect and, therefore, likely classification.

• Any associated defects (particularly relevant for primum defects).

• The size of the defect in two directions if possible (this can be done in

subcostal views with long axis and sagittal planes through the defect).

• Direction and timing of flow from colour flow mapping. Usually

predominantly left to right during systole but with chronic right

ventricle overload flow starts to occur right to left.

• RV size and function.

• RV systolic pressure.

Doppler quantification of shunt

The principle of shunt quantification is comparison of right and left

ventricle stroke volumes. Their ratio (called Qp/Qs) should be 1 but with

shunting to the right the ratio increases and to the left the ratio declines.

Accuracy depends on accurate measures of outflow tract diameter.

• Obtain LVOT PW Doppler vti from apical 5-chamber view and

diameter from parasternal long axis.

Qs =

×(

)

× aortic vti

• Measure RVOT PW Doppler vti and diameter from a parasternal short

axis (aortic valve level) view.

Qp =

×(

)

× pulmonary vti

• Report the ratio Qp/Qs.

ATRIAL SEPTAL DEFECTS

289

ASD with colour flow

demonstrating left to

right flow

Fig. 4.55 Colour flow mapping of atrial septum in subcostal view. See W Video 4.19,

W Video 4.20, W Video 4.21, W Video 4.22.

Primum atrial septal defects and associated defects

Primum defects occur when there is failed development of the primum

septum. To make the diagnosis there must be no atrial septal tissue

extending from the base of the atrio-ventricular valves.

The atrial septal defect on its own is a partial atrio-ventricular canal

defect. If extending to involve the ventricular septum and atrio-ventriular

valves it forms a complete atrio-ventricular canal or endocardial cushion

defect. The valves often have abnormal atrio-ventricular valve rings and

lie in the same plane in apical views (instead of the usual apical displace-

ment of the tricuspid valve i.e. loss of off-setting).

If there is a primum septal defect look for and comment on:

• Inlet ventricular septal defect.

• Cleft mitral valve leaflet—generally involving the anterior mitral

valve leaflet at around ‘12 o’clock’ in the parasternal short axis

(mitral valve level) view. Invariably associated with regurgitation,

often eccentric.

• Mitral and tricuspid regurgitation.

• Partial attachment of the anterior mitral valve leaflet to the

ventricular septum—best seen from the parasternal long axis view

after forward and backward displacement of the probe.

290

CHAPTER 4 Transthoracic chambers and vessels

Patent foramen ovale

If the foramen ovale fails to seal after birth (~20-30% of the popula-

tion) it remains possible for pressure changes in the left and right atria to

reopen the hole. This is of clinical interest because patent foramen ovale

are amenable to percutaneous closure and their presence raise the

possibility that emboli, e.g. clots or fat, could pass from the right heart to

the systemic circulation and cause strokes. Furthermore foramen ovale

are associated with decompression illness and, possibly, migraines.

To identify a patent foramen ovale right-to-left flow needs to be identified

for a short period during the cardiac cycle (flow throughout the cardiac

cycle identifies a septal defect). Sometimes this can be done with colour

flow but usually means contrast is needed (see Chapter 9).

Atrial septal aneurysm

Atrial septal aneurysms are an area of excessive mobility of the atrial

septum and in 75% of cases are associated with patent foramen ovale. The

technical definition is movement of the septum (at least 10mm in width)

away from the normal plane of the septum (to left or right) by 10mm

(Fig. 4.56). Usually the septum will move back and forth as the relative

pressure gradient between atria varies, but may be fixed. Comment on

presence and look for underlying reasons.

292

CHAPTER 4 Transthoracic chambers and vessels

Ventricular septum

Normal anatomy

The ventricular septum divides the left and right ventricle. The ventricular

septum can be divided simply into: (1) a small membranous portion below

the aortic valve and forming part of the left ventricular outflow tract, and

(2) a muscular septum, spreading inferiorly, anteriorly and apically. These

have separate embryological origins.

The muscular septum can be subdivided into 3 areas: the inlet septum

between the mitral and tricuspid valves; the trabecular septum extending

to the apex and forming the bulk of the septum on echocardiographic

views; and the outlet septum close to the aortic and pulmonary valves.

These subdivisions are used to classify ventricular septal defects.

Normal findings

Views

Any view that studies the ventricles can also be used to study the ventricular

septum. Therefore, parasternal long and short axis views, apical 4-, 5-, and

3-chamber and subcostal are all useful (Fig. 4.57).

Findings

• Parasternal long axis: the membranous septum (or sometimes part

of the muscular outlet septum) is seen in the LVOT, with the mid

segments of the trabecular (muscular) septum lying to the left.

• Parasternal short axis (aortic valve level): the membranous and outlet

septum are seen around the aortic ring.

• Parasternal short axis (midpapillary muscle level): the septum lies

between the right and left ventricle and mainly consists of the

muscular (trabecular) septum. The muscular inlet septum may be seen

at the bottom of the septum.

• Apical 4- and 5-chamber: the trabeculated (muscular) septum can be

viewed right up to the apex. In a 4-chamber view the muscular inlet

septum is seen between mitral and tricuspid valves. In the 5-chamber

view the membranous septum by the aortic valve comes into view.

• Subcostal view: the septum lies perpendicular to the probe and this

view provides an opportunity for aligning colour flow mapping and

Doppler through the septum.

294

CHAPTER 4 Transthoracic chambers and vessels

Ventricular septal defects

Ventricular septal defects are one of the common congenital heart defects.

They can occur anywhere within the septum and are named according to

their location—membranous or muscular (inlet, outlet, or trabeculated)

(Fig. 4.58). If they involve both the membranous and muscular septum

they are called peri-membranous. Gerbode defects are a specific type from

left ventricle to right atrium. As well as being congenital they can occur

due to ischaemia (post infarction, often quite apical in trabecular septum

with multiple holes) or be iatrogenic following cardiac surgery or pacing.

Membranous (and peri-membranous) are easiest to identify, with muscular

defects the most often missed because the defect is small or altered in

shape by ventricular contraction.

Assessment

Initial assessment should be with 2D imaging, followed by colour flow.

Doppler can quantify the size of any shunt.

2D and colour flow imaging

• Study the septum in all views and look for gaps. To avoid overcalling

septal drop-out the defect should be apparent in different planes.

• Colour flow imaging over the septum, particularly in the subcostal and

parasternal views, is essential to scan for abnormal colour flow jets

appearing in the right ventricle and originating from the septum.

• The septum is curved and can not be seen entirely in one plane.

Peri-membranous defects are easiest to see in parasternal long axis

and short axis (aortic valve level) views with tilting to scan through

the septum. These views also identify outlet defects, which can be

differentiated from peri-membranous defects because they lie nearer

the pulmonary valve. The inlet and trabecular defects are better seen

in apical and subcostal views but may need probe tilting to scan the

septum.

Comment on

• Position of the defect and, therefore, likely classification.

• Characteristics of the defect, e.g. multiple small defects.

• Size of the defect (in 2 directions if possible, e.g. subcostal views with

long axis and sagittal planes through the defect). Measure size from 2D

images or colour flow jet.

• Direction and timing of flow from colour flow mapping. With large

chronic defects right ventricular pressure will increase and the left-

to-right flow will reduce. Colour flow may be less evident.

• If possible, use PW or CW Doppler aligned across the defect to

measure the pressure gradient between ventricles using the Bernouli

equation (= 4 × velocity2). Right ventricular pressure can be measured

from the pressure gradient. If the aortic valve is normal then systolic

blood pressure will equal left ventricular systolic pressure. Right

ventricular systolic pressure = systolic blood pressure—gradient

across the defect.

• Left and right ventricle size and function, as well as evidence of right

ventricle pressure or volume overload (b p.276).

• Associated problems, e.g. aortic valve dysfunction and regurgitation.

296

CHAPTER 4 Transthoracic chambers and vessels

Pericardium

Normal anatomy

The pericardium surrounds the heart. An outer, supportive, fibrous peri-

cardium blends superiorly into the aorta and pulmonary arteries and infe-

riorly attaches by ligaments to the diaphragm, sternum and vertebrae. On

the inside of the fibrous layer and the outer surface of the heart are two

serous membranes which allow the heart to move. There are two irregular

holes through the membranes; one around the aorta and pulmonary

arteries, and the other around the pulmonary veins and vena cavae. The

membranes join around the edges of the holes to create an enclosed,

‘deflated’ sac which can fill with fluid. Because they wrap round the blood

vessels two pockets (or sinuses) are created; the transverse sinus between

aorta and pulmonary artery, and the oblique sinus between the pulmonary

veins on the back of the left atrium. These are important because localized

collections can form in the pockets.

Normal findings

Views

• Part of the pericardium can be seen in all views and should be studied

in all scan planes—only part of the pericardium may be affected in

disease or there may be a localized collection.

• The best views are: parasternal long and short axis, apical 4-chamber,

and subcostal (Fig. 4.59).

Pericardium

• The pericardial surfaces are difficult to see because they adhere to

surrounding structures but may appear as a thin, slightly brighter line

around the heart.

• Measures of pericardial thickness do not correlate well with pathology

specimens but the pericardium is normally 1-2mm thick. CT or

magnetic resonance imaging should be used to measure thickness.

Pericardial space

• The pericardial space is seen as a black line around the heart. It is

normal to have a few millimetres of fluid.

Distinguishing pericardial from pleural fluid

In the parasternal long axis view use the descending aorta as a landmark.

The pericardial sac tucks in between the aorta and left atrium, so peri-

cardial fluid will extend up to the gap and lie in front of the aorta. Pleural

fluid will track behind the aorta and over the left atrium.

If both pericardial and pleural fluid are suspected look for the pericardium

lying as a continuous dividing line within the fluid in an apical view.

298

CHAPTER 4 Transthoracic chambers and vessels

Pericardial effusion

Amount of pericardial fluid

• Measure fluid thickness using 2D or M-mode in several places and

views. Report the depth and where the measurement was made.

• For global effusions, grade as mild, moderate, or large based on depth

(depth also approximates to volume of fluid).

•

<0.5cm

Minimal

50-100mL

•

0.5-1cm

Mild

100-250mL

•

1-2cm

Moderate

250-500mL

• >2cm

Large

>500mL

• More accurate volume measures can be made with planimetry from

traced pericardial and heart borders in apical views. It is possible to

produce even more accurate measures with 3D echocardiography,

although there is not usually any clinical indication.

Thickness does not relate to clinical severity

Rapid accumulation of a small quantity can have as severe a haemodynamic

effect as slow accumulation of a large quantity. Look for features of

tamponade.

Appearance of pericardial space

• Fluid is the black echolucent area and will be serous, blood, or pus. It is

difficult to differentiate with echocardiography.

• Strands (fibrin) can occur in any condition which causes inflammation

(infection, haemorrhage, or uraemia) (Fig. 4.60).

• Masses are more unusual and could be haematoma, tumour,

cyst, or related to infection, e.g. fungus. Comment on size, shape,

appearance, movement, attachments to surfaces, e.g. pericardium,

ventricle. Haematoma is usually the same echocardiographic

density as myocardium—so may be difficult to see—but suggests a

haemopericardium.

Localization Look at effusion in all views and comment whether global

(most common) or localized. Specify where the effusion is localized.

Problems with localized effusions

• Suspect localized effusions after cardiac surgery (blood) or infections

(loculation). Localized effusions may only be evident because

of restricted pulmonary vein flow (oblique sinus) or unusual

compression of a cardiac chamber. Consider transoesophageal

echocardiography in patients with haemodynamic problems after

cardiac surgery to look for localized effusions.

• Apparent posterior localization may be because a small effusion has

shifted posteriorly due to gravity in a supine patient.

• A localized anterior space in parasternal views may actually be

mediastinal (e.g. fat, fibrosis, thymus).

Evidence of cardiac tamponade see b p.300.

300

CHAPTER 4 Transthoracic chambers and vessels

Cardiac tamponade

Cardiac tamponade is a clinical diagnosis based on tachycardia (>100bpm),

hypotension (<100mmHg systolic), pulsus paradoxus (>10mmHg drop

in blood pressure on inspiration), raised JVP with prominent x descent.

Echocardiography provides supporting evidence.

2D findings suggestive of tamponade (Fig. 4.61)

As intrapericardial pressure rises and begins to exceed right heart pres-

sure, parts of the cardiac chambers collapse during the cardiac cycle.

Clinical signs usually appear before the left heart is affected.

• Right atrium appears to collapse faster than usual in atrial systole.

• Parts of right ventricle start to collapse during ventricular diastole. First

the right ventricular outflow during early diastole (at lowest pressure)

then as intrapericardial pressure increases collapse extends to involve

whole of right ventricle and whole of diastole.

• Combination of rapid atrial collapse in atrial systole followed by rapid

ventricular collapse in ventricular diastole creates the appearance of a

‘swinging right atrium and ventricle’.

Doppler findings suggestive of tamponade

Doppler findings in tamponade are the echocardiographic demonstration

of the exaggerated variation in right and left ventricle inflow during

respiration—clinically demonstrated as pulsus paradoxus.

• In an apical 4-chamber view place PW Doppler at tricuspid valve

inflow. Switch on physiological respiration trace (if available) and slow

sweep speed to 25cm/s.

• Acquire a tracing and measure maximum and minimum E-wave

velocities (these correspond with respiration: maximum in inspiration).

• Do the same at the mitral valve (E-wave maximum in expiration).

• Normal variation is <15% at mitral valve and <25% at tricuspid valve.

Greater than this supports tamponade but clinical signs are usually

associated with ~40% variation at the mitral valve.

Exaggerated flow changes through the heart during respiration can also be

demonstrated in the left and right ventricle outflow tracts (increased flow

in inspiration on the right and in expiration on the left).

• Use PW Doppler in RVOT in parasternal short axis. Record vti and

peak velocity in inspiration and expiration.

• Do the same at the LVOT in apical 5-chamber.

• Normally vti and peak velocity vary <10% during respiration.

Problems with assessment of tamponade

2D and Doppler measures are only accurate with ‘normal’ relations

between intrapericardial, intrathoracic, and intraventricular pressures.

Increased ventricular ‘stiffness’ (ventricular hypertrophy, intraventricular

haematoma) or increased right ventricular pressure (pulmonary hyper-

tension) makes the ventricle less likely to collapse. Low volume states

mean the change in ventricular inflow on Doppler is less pronounced.

Doppler indices are not validated in ventilated patients.

CARDIAC TAMPONADE

301

Pulsus paradoxus

There is normally a swing of 5mmH2O in intrathoracic pressure with res-

piration. Inspiration leads to an increase in blood flow into the lungs and

therefore an increase in flow into the right heart and reduced flow into

the left heart. Expiration forces blood out of the lungs and increases flow

into the left heart and reduces flow into the right heart. This accounts for

the normal variation in blood pressure (‘left-sided pressures’) with respi-

ration. Increased pericardial fluid increases intrapericardial pressure. Left

and right ventricular filling is impaired and this filling is exacerbated on

the left on inspiration leading to an exaggerated drop in blood pressure

on inspiration.

Changes in 2D and Doppler with increasing tamponade

1. Tricuspid valve inflow pattern.

2. Mitral valve inflow pattern.

3. Abnormal right atrial collapse in atrial systole.

4. Right ventricular outflow collapse in ventricular diastole.

5. Left ventricular outflow collapse in ventricular diastole.

Start of right atrial collapse

in atrial systole

Right ventricular collapse in

ventricular diastole

Fig. 4.61 Subcostal long axis view showing early atrial systolic collapse and

ventricular diastolic collapse.

302

CHAPTER 4 Transthoracic chambers and vessels

Constrictive pericarditis

Constrictive pericarditis is uncommon and often has vague signs and

symptoms with a long history. It can be due to chronic inflammation

as a result of infection (classically tuberculosis), cardiothoracic surgery,

radiation, or connective tissue disease. It can be transient with pericardial

inflammation. Diagnosis is clinical. Echocardiography can be supportive

and differentiate from restrictive cardiomyopathy. Magnetic resonance

imaging or CT are also usually required to assess the pericardium.

2D findings suggestive of constriction

• Look for the pericardium: may appear normal thickness (1-2mm) or

thickened (up to 10mm) (measurements are inaccurate so use other

modalities for actual measures). May appear bright or there may be

shadowing from calcium (a marker of chronic inflammation).

• Assess the left ventricle: usually normal systolic function—consider

other causes if not. Assess septal motion in parasternal views with 2D

and M-mode. Classically, septum appears to ‘flutter’ as left and right

ventricles fill during diastole. Probably due to waves of competitive

filling of the 2 ventricles. Seen as early diastolic notching on M-mode,

or paradoxical and then normal motion on 2D.

CONSTRICTIVE PERICARDITIS

303

Differentiation from restrictive cardiomyopathy (Table 4.9)

Table 4.9 Clinical features of constrictive pericarditis and restrictive

cardiomyopathy are similar. Echocardiography is useful to differentiate

Restrictive

Constrictive pericarditis

cardiomyopathy

Similarities between conditions:

E/A ratio

Increased

Deceleration time

Decreased

Differences between conditions:

LV function

May be abnormal

Usually normal

Pericardium

Normal

May be bright or thick

Septal motion

Usually normal

May be abnormal

Atria

Biatrial enlargement Usually normal size

Mitral annulus velocity Decreased

Normal

Ventricular inflow

Normal variation

Increased variation on respiration

304

CHAPTER 4 Transthoracic chambers and vessels

Doppler findings suggestive of constriction

• Assess mitral and tricuspid inflow during respiration just as for

tamponade (Fig. 4.62). Constrictive pericarditis causes the same

changes as tamponade (>25% variation at tricuspid and >15% at

mitral). As the ventricles are supported by ‘stiff’ pericardium no

ventricular collapse.

• Look for features of diastolic dysfunction (b p.246). Exaggerated E/A

ratio on mitral inflow and shortened deceleration time (time from

peak to end of E-wave: normal >160ms).

• Use tissue Doppler (if available). In apical 4-chamber place cursor on

lateral mitral annulus. In constrictive pericarditis myocardial function is

normal and peak mitral annulus velocity is therefore normal (>10mm/s).

If reduced, consider restrictive cardiomyopathy (Fig. 4.63).

306

CHAPTER 4 Transthoracic chambers and vessels

Congenital pericardial disease

Congenital absence of pericardium is rare. Usually suspected in 2D because

of an obvious gap or herniation of part of the heart (often left or right

atrial appendage or parts of ventricle). The heart may be abnormally

positioned with right atrial or ventricular dilatation and paradoxical septal

motion. Record where the pericardium is missing and any functional

effects of herniation.

Congenital pericardial cysts are more common. Usually benign. Comment

on size, mobility, position, attachment, appearance (fluid, masses).

Pericardial tumours

Primary cardiac tumours or metastatic tumours can involve the pericardium.

Comment on any masses, reporting the position, size, appearance, attach-

ments, and functional effects on cardiac function.

Acute pericarditis

There are no echocardiographic features diagnostic of acute pericarditis.

Echocardiography should be used in suspected pericarditis to look for:

• Complications (e.g. effusions).

• Left ventricular function (e.g. abnormal function may suggest

myocarditis).

• Underlying causes (e.g. tumour or regional wall motion abnormalities

suggestive of myocardial infarction).

• Other causes for clinical signs (e.g. endocarditis, pericardial effusion).

Pericardiocentesis

Echocardiography is very useful during pericardiocentesis. Pericardio-

centesis is usually done from subcostal or apical positions so assess

pericardial fluid in both views (Fig. 4.64).

Before the procedure record:

• Depth of fluid in each position.

• Depth from skin to the outer boundary of fluid (a guide as to how far

to introduce the needle).

During the procedure:

• Angle of the echo probe to achieve images can be a guide to the angle

to be used for the needle.

• The needle can sometimes be seen advancing into pericardial space.

• If unclear whether needle is in pericardial space, inject agitated saline

contrast down needle. Contrast should be seen clearly filling the

pericardial space if needle is correctly positioned . . . or filling another

cardiac chamber if not!

308

CHAPTER 4 Transthoracic chambers and vessels

Aorta

Normal anatomy

The aorta is the main conductance artery of the body, carrying blood

from the heart to all major branch vessels. It has a functional role, distend-

ing during systole and recoiling in diastole, to propel blood. The aortic

wall has 3 layers: tunica intima, a thin inner layer, lined by endothelium;

tunica media, a thicker middle layer of elastic tissue for tensile strength and

elasticity; tunica adventitia, a thin outer layer, predominantly collagen,

housing the vasa vasorum and lymphatics.

There are 4 major sections: (1) ascending aorta from aortic valve annulus

including sinuses of Valsalva, sinotubular junction (the narrowest point)

and up to right brachiocephalic artery; (2) aortic arch from brachiocephalic

to aortic isthmus (just distal to left subclavian artery); (3) descending aorta

from isthmus to diaphragm; (4) abdominal aorta from diaphragm to aortic

bifurcation and origin of iliac arteries.

Normal findings

Views

Parts of the aorta can be seen in all windows (Fig. 4.65). Full evaluation

requires a combination of views and additional, non-standard transducer

positions.

Proximal ascending aorta

• Proximal ascending aorta is best seen in the parasternal long axis view.

Additional views include, particularly if dilated, the right parasternal

views or left parasternal views from higher intercostal spaces for

ascending aorta, (particularly with patient in extreme left lateral

position to bring aorta more anterior). Doppler interrogation is limited

to qualitative assessment of flow and aortic regurgitation severity.

• Apical views: the ascending aorta can also be visualized in apical

5- and 3-chamber views. 2D image quality is limited at this depth but

orientation is optimal for Doppler to assess aortic regurgitation.

Aortic arch

• Suprasternal views (and supraclavicular views) allow assessment

of aortic arch and brachiocephalic vessels. Both transverse and

longitudinal views are possible but the latter is most useful to identify

head and neck vessels. Descending aorta is only partially in plane and,

artefactually, appears to taper. Descending aorta blood flow can be

used to assess aortic regurgitation severity and aortic coarctation.

Descending thoracic aorta

• Descending thoracic aorta is seen in cross-section posterior to

the left atrium in the parasternal views. The proximal segment of

descending aorta is seen in the suprasternal view. Additional views of

the longitudinal section of the descending thoracic aorta can normally

be visualized from an apical 2-chamber view with lateral angulation and

clockwise rotation of probe. The distal thoracic aorta and proximal

abdominal aorta can be visualized from the subcostal view.

310

CHAPTER 4 Transthoracic chambers and vessels

Aortic size

The terms proximal aorta or aortic root refer to the aortic annulus,

sinuses of Valsalva, sinotubular junction, and proximal ascending aorta.

Measurement of the aortic root is of crucial importance in the diagnosis of

Marfan syndrome, and in the serial monitoring of patients with, or at risk

of, progressive dilation of the ascending aorta. While a single measure-

ment of the proximal aorta may suffice in the normal examination, when

monitoring aortic root dilatation a minimum of 4 measurements should be

routinely made and recorded from the parasternal long axis view.

Different methods for assessing aortic root dilation are quoted in the

literature (e.g. systolic versus diastolic measurement; inner to inner or

leading edge to leading edge dimensions). Normative data in adults were

calculated using leading edge methodology in diastole. However, to try

and achieve consistency with both other chamber measurements and

other imaging methods it is now more common to measure inner edge to

inner edge at the widest diameter, i.e. in systole. Differences are likely to

be small but it is important that the method used is stated and consistent

methodology used in follow-up.

Assessment (Fig. 4.66)

• Make measurements from a parasternal long axis view in systole (with

valve leaflet tips open to their maximum).

• 2D measurement at the sinuses gives higher values than M-mode

measurements and are preferred. Make measurements parallel to

aortic annular plane from inner edge to inner edge.

• A complete assessment includes measurement of:

• Annulus (normal 2.3 ± 0.3cm).

• Sinus of Valsalva, at aortic leaflet tip level (normal 3.4 ± 0.3cm;

<2.1cm/m2).

• Sinotubular junction.

• Proximal ascending aorta (normal 2.6 ± 0.3cm).

• Comment on how the measurements were made and use the

appropriate normal values. In a normal study a single aortic diameter

may be sufficient. When possible, report size relative to body

surface area.

• Where needed, continue the assessment by providing measurements

of the arch from suprasternal views, descending aorta from parasternal

views and, for completeness, abdominal aorta from subcostal views.

• Aortic arch.

• Descending thoracic aorta (normal <1.6 cm/m2).

• Abdominal aorta (normal <3 cm; <1.6 cm/m2).

AORTIC SIZE

311

Serial measurements and identification of dilatation

• In serial measurements the annulus is not prone to dilation. Any

significant change should raise suspicion of methodological error and

caution over interpreting measurements elsewhere. In effect, the

annulus acts as a control for serial studies.

• Measurements at the sinus of Valsalva are the key. They tend to be

the site of initial ectasia when the aortic root does dilate in Marfan

syndrome. In the normal adult it measures <3.7cm but can vary

with body surface area (Fig. 4.67). Normograms that adjust for body

surface area maximize sensitivity for the detection of aortic dilation

in adults, but for practical purposes the upper normal limit in the

adult is 2.1cm/m2 and anything below this can be reported as normal.

Aortic

Sinus of

Sinotubular

Ascending

annulus

valsalva

junction

aorta

Aortic arch

Descending aorta

Fig. 4.66 Measurement of aortic size at key locations from parasternal long axis

(top) and suprasternal (bottom) views.

312

CHAPTER 4 Transthoracic chambers and vessels

Calculating a z-score: Cornell data-based formulae for

children and adults in different ranges of age

Z-scores for aortic root size are used extensively in the new Ghent

criteria for Marfan syndrome. Therefore it is important to know what

they are.

A z-score is a way to take account of expected variability in a measure

so that you can assess how abnormal the value you have obtained really

is. The z-score represents the proportion of a standard deviation that

the value you have measured lies away from the expected mean for that

measure, given the level of another factor. For example, the distribution

of aortic root size varies with age. Therefore, you can not know if the

aortic root size you measure is abnormal unless you know what the

normal range is for the age group of patient you are studying. For aortic

root size this is further complicated by the fact that aortic root size also

varies with body surface area so this also needs to be taken into account

in the z-score. The formulae listed here allow you to calculate an ‘aortic

root size’ z-score for different age groups based on what the predicated

aortic root size would be for the patient body surface area. To use these

formulae you need to know for your patient their: 1) age, 2) body surface

area 3) measured aortic root diameter (originally measured in diastole—

leading edge to leading edge; inner edge measurements in systole now

recommended). Then, choose the formulae below that suit the age of

the patient and calculate their predicted aortic root size using the patient’s

body surface area. Then, calculate the z-score using the measured root

diameter and the predicted root diameter. This number tells you how

many standard deviations the patient lies away from the mean.

Age up to 15:

Mean predicted aortic root (cm) = 1.02 + 0.98 × BSA

Z = (Measured root diameter - predicted aortic root diameter)/0.18

Age 20 to 40:

Mean predicted aortic root (cm) = 0.97 + 1.12 × BSA

Z = (Measured root diameter - predicted aortic root diameter)/0.24

Age >40

Mean predicted aortic root (cm) = 1.92 + 0.74 × BSA

Z = (Measured root diameter - predicted aortic root diameter)/0.37.

Mean predicted aortic root size is based on Dubois formula.

314

CHAPTER 4 Transthoracic chambers and vessels

Aortic dilatation

General (Fig. 4.68)

Dilatation of the aorta is an increase in diameter more than expected for

age and body size and is the most commonly identified aortic abnormality.

When localized to the sinus of Valsalva the risk of complications is

significantly lower than when there is generalized aortic dilatation but still

higher than no dilatation! Causes include: degenerative disease (hyper-

tension, atherosclerosis, cystic medical necrosis, post-stenotic); collagen

vascular disease (Marfan syndrome, Ehlers-Danlos, Loeys-Dietz, familial

aortic aneurysm); inflammatory disorders (rheumatoid, systemic lupus

erythematosus, ankylosing spondylitis, Reiter syndrome, syphilis, aortic

arteritis); trauma (blunt or penetrating).

Assessment

Measure the degree of dilatation at multiple positions and report where

and how the measurements were made.

Differentiation of degenerative dilatation from Marfan

When the aorta dilates due to degenerative disease, the contours of the

sinuses of Valsalva and the normal slight narrowing at the sinotubular

junction are maintained. In contrast, dilatation of the aorta in Marfan

syndrome is characterized by enlargement of the sinuses of Valsalva,

resulting in loss of narrowing at the sinotubular junction.

Indications for considering elective aortic root

replacement

• Aortic diameter 45mm in adults with connective tissue disease,

especially if a family history of aortic dissection.

• Aortic diameter 50mm in patients with bicuspid aortic valve

disease.

• Aortic diameter 55mm in adults without connective tissue

(atherosclerotic aneurysm).

• Rapid change in the aortic root size: >5mm per year.

If there is an indication for aortic valve replacement, lower thresholds

can be used: concomitant root replacement should be considered if

aortic diameter 40 mm.

There is an increased risk in pregnancy. If the aortic diameter is 40 mm,

monitoring with echocardiography and clinical examination should be

considered monthly. Progressive root dilatation to 45 mm should lead

to consideration of surgery prior to, or contemporaneous with, delivery

of the child. Special precautions would also be required at the time of

delivery which should take place under the care of a specialist team

managing complex pregnancy with cardiac disease.

316

CHAPTER 4 Transthoracic chambers and vessels

Marfan syndrome

Marfan syndrome is an autosomal dominant connective tissue disorder due

to mutation in the Fibrillin 1 gene. It is a multisystem disorder that affects

both locomotor and cardiovascular systems, and the eyes. The incidence

is approximately 1 in 10,000 births of whom approximately 26% are a spon-

taneous mutation, i.e. have no family history. Many individuals have some

of the skeletal features of Marfan syndrome without the actual condition

and the diagnosis is dependent on diagnostic criteria (Ghent criteria).

Assessment

Echocardiography is key for the criteria and should concentrate on aortic

root dimensions (Fig. 4.69). To correct for body size, either a Z-score

should be calculated using a validated formula, with the Cornell formula

the most commonly used, or aortic root dimensions plotted on a validated

nomogram against body surface area. An aortic Z-score of 2 supports

diagnosis of Marfan syndrome. Previous or newly diagnosed aortic root

dissection carries the same weight.

The presence of mitral valve prolapse, diagnosed as per standard practice

(see b p.128), scores 1 in the systemic score (which has replaced minor

criteria) and its presence and severity should therefore also be reported.

2010 Revised Ghent Nosology for Marfan syndrome

Marfan syndrome should be diagnosed if any 1 of these 7 rules is fulfilled:

If no family history of Marfan syndrome:

1. Aortic Z 2 and Ectopia lentis

2. Aortic Z 2 and Fibrillin 1 gene mutation

3. Aortic Z 2 and Systemic score 7

4. Ectopia lentis and Fibrillin 1 gene mutation with known aortic

aneurysm

If positive family history of Marfan syndrome:

5. Ectopia Lentis and confirmed family history

6. Systemic score 7 and confirmed family history

7. Aortic Z score 2 if over 20 years, 3 if below 20 years, and

confirmed family history.

For explanation of Z-score see b p.312.

318

CHAPTER 4 Transthoracic chambers and vessels

Aortic dissection

General

Aortic dissection originates from an intimal tear, leading to subintimal

haemorrhage which can extend within a false lumen back to the aortic valve

or forwards, throughout the aorta. Aortic dissection is life threatening,

with an early mortality of 1% per hour. Presentation is usually with severe

chest pain. The differential includes other causes of chest pain such as

acute myocardial infarction or chest wall pain, and aortic intramural

haemorrhage or expanding thoracic aneurysm. Risk factors for dissection

include: Marfan syndrome, aortic dilatation/aneurysm, hypertension, aortic

valve disease—particularly bicuspid valve (risk 5× normal).

The Stanford classification is the simplest and most pragmatic.

• Type A: involvement of the ascending aorta irrespective of

involvement elsewhere.

• Type B: limited to the arch and/or descending thoracic aorta.

Assessment

Prompt diagnosis is crucial and transthoracic echocardiography is of value

in initial management. Examine for diagnostic features and for secondary

complications. A negative transthoracic study does not exclude aortic dis-

section and where there is a high index of suspicion further imaging with

TOE, CT, or magnetic resonance imaging will be required.

Diagnostic features

• Look for the presence or absence of any possible dissection flap in all

aortic views (parasternal, suprasternal, subcostal) (Fig. 4.70). A flap will

appear as a linear mobile structure with motion independent of the

aortic wall.

• 3D echocardiography can confirm presence of dissection flap—which

will appear as sheet-like structure—and extent, helping to exclude or

confirm involvement of coronary ostia.

• Look for a false lumen using colour flow Doppler placed over the

aorta in all aortic views. There will be different patterns of flow in the

true and false lumen.

Beam-width artefact and reverberation

• Beam-width artefact and reverberation can mimic a dissection flap.

• M-mode of aortic wall motion and a suspected flap will demonstrate

flap motion which is different from aortic wall movement, whereas a

reverberation artefact will move with the wall.

Secondary complications

• Measure aortic root size from parasternal views, size of arch and

descending aorta from suprasternal views, and size of descending

thoracic and abdominal aorta from subcostal views.

• Comment on and quantify aortic regurgitation.

320

CHAPTER 4 Transthoracic chambers and vessels

Aortic coarctation

General

Aortic coarctation is a congenital narrowing in the proximal descending

thoracic aorta, usually located immediately proximal to the entry site of

the ductus arteriosus. It may be suspected in a patient with hypertension

and a weak femoral pulse, radiofemoral delay or systolic murmur. Aortic

coarctation first diagnosed in adulthood is usually asymptomatic as the

stenosis is not usually severe and collaterals are present. 50-80% will have

a bicuspid aortic valve and other cardiac abnormalities (e.g. subaortic

membrane, supravalvular aortic stenosis).

Assessment

Echocardiography is required in diagnosis and follow-up. Aortic coarctation

can be relatively complex and further imaging (usually magnetic resonance

imaging) is performed if intervention is being considered.

Diagnosis

The suprasternal view is the most useful.

• Identify the brachiocephalic vessels—coarctation usually occurs just

distal to the left subclavian with post-stenotic dilatation common.

• Use colour flow mapping of the descending aorta to identify a high-

velocity narrowed flow stream with turbulence (even if 2D poor).

• Place CW Doppler through the point of maximum colour flow

turbulence to measure a typical systolic velocity gradient. The gradient

will typically persist to end diastole (‘diastolic tail’) (Fig. 4.71).

• CW Doppler tends to overestimate the gradient and better

correlation with catheter gradients can be obtained if the proximal

velocity is measured with PW Doppler and the modified Bernoulli

equation used to calculate flow.

• If coarctation is suspected but difficult to image, CW Doppler using a

pencil probe in the suprasternal position will often allow measurement

of a gradient in the descending aorta.

Follow-up

All patients with previous repair of coarctation of the aorta should be

followed up throughout adult life. Echocardiography should be repeated

annually. Where visualization is inadequate alternative imaging such as CT

or magnetic resonance imaging may be needed.

• Examine and report the residual gradient.

• Look for abnormalities in the aorta and comment on development of

any aneurysm at the site of previous repair.

• Reassess the aortic valve annually: early degenerative disease is

common (sometimes in previously unrecognized bicuspid valve).

322

CHAPTER 4 Transthoracic chambers and vessels

Sinus of Valsalva aneurysm

Sinus of Valsalva aneurysms can be congenital resulting from incomplete

fusion of the distal bulbar septum that divides the aorta and pulmonary

arteries. They tend to have a long sac of mobile tissue projecting into ad-

jacent structures, forming a ‘wind sock’ appearance. Acquired aneurysms,

usually due to endocarditis, lead to more symmetrical dilation, with no

excess tissue. If rupture occurs, a fistula develops between aorta and adja-

cent chamber, with left-to-right shunting and clinical features that can vary

in severity from acute haemodynamic compromise to a new continuous

murmur. 85% affect right coronary sinus and project/rupture into the right

ventricle; 10% affect non-coronary sinus and project/rupture into the right

atrium; 5% affect left coronary sinus and project/rupture into the left atrium.

Assessment

• Use parasternal long and short axis views to diagnose and measure

(Fig. 4.72).

• If rupture suspected, use parasternal short axis view at and above

the aortic valve. Colour flow mapping will usually confirm site of

communication and continuous flow. If possible the coronary artery

should be visualized to exclude coronary artery fistulae.

• CW Doppler will show a high velocity systolic and diastolic signal.

• Comment on the size of the right atrium (which reflects acute right

atrial overload) and left atrial and left ventricular size (which will

reflect the extent of chronic volume overload).

• 3D echocardiography may be helpful in planning particular surgical or

percutaneous approach to repair. Image the aortic valve in parasternal

long axis view before acquiring a full 3D volume set.

324

CHAPTER 4 Transthoracic chambers and vessels

Aortic atherosclerosis

General

Atherosclerosis of the aorta can result in dilatation, aneurysm, or dissection

and is a risk factor for coexisting coronary artery disease and cerebrovascular

disease.

Assessment

Aortic atheroma can be visualized with transthoracic echocardiography

(although transoesophageal is more appropriate) in either the proximal

ascending aorta or, more commonly, in the descending abdominal aorta.

Atherosclerotic thoracic aortic aneurysm may also be detected by tran-

sthoracic imaging, either at the aortic root or behind the left atrium in

the descending thoracic aorta (parasternal long axis view). More rarely,

descending abdominal aortic aneurysm may be picked up in subcostal

views (Fig. 4.73). The extent of the aneurysm cannot usually be accurately

quantified, but the extent of dilatation and presence or absence of laminar

thrombus can be commented upon. Further imaging will frequently be

required.

326

CHAPTER 4 Transthoracic chambers and vessels

Cardiac tumours

One of the most ‘exciting’ things to see in echocardiography is a cardiac

mass that should not be there. Once seen it is easy to forget about con-

tinuing with the systematic collection of information but this is essential in

order to understand what effect any mass may be having. Masses will be

vegetations, cysts, tumours (benign and malignant), or thrombus (Figs. 4.74

and 4.75).

Primary tumours—benign (80%)

Myxoma

Myxoma is the most common primary tumour (30% of tumours: 74% left

atrium, 18% right atrium, 4% left ventricle free wall). 10% are familial so

family counselling should be considered if other familial cases.

Appearances and assessment

Globular, finely speckled mass with well-defined edges. May prolapse into

left ventricle. Usually attached to interatrial septum (fossa ovalis 90%).

Attachment best visualized in apical and subcostal

4-chamber views.

Tumour calcification may be seen infrequently. Determine length and

diameter of myxoma. Quantify severity of coexisting mitral regurgitation

or effective stenosis caused by myxoma.

Myxoma or thrombus?

No specific finding differentiates the two but thrombus is more often

irregular, layered, immobile, broad-based (myxoma typically has a stalk)

and located near the posterior wall of the left atrium. The left atrium is

more likely to be dilated with an abnormal mitral valve.

Papillary fibroelastoma

10% of primary tumours. Found attached most commonly to mitral and aortic

valves with small pedicles. Rarely attach to LVOT or papillary muscles.

Appearances and assessment

Small (rarely >1cm in diameter), mobile, pedunculated, echocardiograph-

ically-dense mass. May mimic vegetation or Lambl’s excrescences. Usually

no other valve abnormalities. Comment on size, location, and functional

effects.

Other tumours

Lipoma (10%), fibroma (4%), rhabdomyoma (9%—children more common).

Primary tumours—malignant (20%)

Typical tumours are sarcomas, angiosarcomas and rhabdomyosarcomas.

Primary lymphomas also reported. Final diagnosis often requires biopsy.

Appearances and assessment

Often irregular and invade into myocardium. Can be recognized as unusual,

localized myocardial thickening. Report location, extent, and functional

effects (valve or ventricle dysfunction, restrictive or constrictive physiology,

pericardial fluid). Comment on concerns about cause.

328

CHAPTER 4 Transthoracic chambers and vessels

Secondary tumours—metastases

40 times more common than primary malignant tumours. Cardiac metas-

tases occur in 5% of patients who die of malignant tumours. Most common

tumours to metastasize to heart are: melanoma, bronchogenic carcinoma,

breast cancer, lymphoma, gastrointestinal adenocarcinoma, laryngeal car-

cinoma, pancreatic cancer, mucinous adenocarcinoma of cervix/ovary.

Often clinical presentation is with tachycardia, arrhythmias, or heart failure

and most common finding is a pericardial effusion.

Appearances and assessment

Usually seen as wall thickening and there may be an associated pericardial

effusion. Tumour mass may protrude into a cardiac chamber. Comment

on size, location, and functional effects.

Valve cysts

Fluid-filled cysts can be found on valves often due to myxomatous degen-

eration. They appear as round structures, often with a pedicle attachment.

The cyst has a fluid-filled appearance and there may be floating structures

inside. Comment on location, size, and functional effects.

Pericardial cyst

Cysts can form in pleura or pericardium. Most commonly cysts are seen

around the right costophrenic location (70%), then left costophrenic angle

(30%) and rarely in upper mediastinum, hila, or left cardiac border.

Appearances and assessment

Pericardial cysts appear as an ovoid space adjacent to a cardiac chamber.

The differential is between cyst and loculated pericardial effusion, dilated

coronary sinus or ventricular pseudo-aneurysm.

Extra-cardiac tumours

Tumours within the thorax, but separate from the heart, can be incidentally

picked up during echocardiography. Parasternal views identify mediastinal

cysts or thymomas. Other extra-cardiac tumours include haematoma,

teratoma, diaphragmatic hernia, and pancreatic cysts.

Appearances and assessment

Comment on location, suspected cause, and functional effects. Key effects

are displacement of the heart, compression of cardiac chambers, evidence

of superior vena cava obstruction, cardiac tamponade, constrictive peri-

carditis, pulmonary or tricuspid stenosis.

330

CHAPTER 4 Transthoracic chambers and vessels

Congenital heart disease

Background

Common congenital heart defects, such as atrial and ventricular septal

defects (b pp.288, 292) and coarctation of the aorta (b p.320) have

distinct methods of assessment using standard techniques. More complex

congenital disease is dealt with in specialist texts. Imaging of any congenital

heart disease, simple or complex, relies on the same basic echocardio-

graphic principles and should not be alarming. All images must be acquired

and assessed. If complex, liaise closely with a specialist congenital centre.

It is also worth remembering that echocardiography complements other

imaging tools and a range of imaging modalities are required in the

management of patients with congenital heart disease.

Assessment

Try to obtain as much patient detail as possible prior to scanning such

as operation notes, previous procedures and results of previous imaging

investigations. This will immediately tell you what you might expect to be

seeing and what views may be most useful or required. When starting to

image remember:

• Do not be scared: apply basic principles of transthoracic

echocardiography—assessment of ventricular function, valvular

function, and presence of a pericardial effusion is usually possible in

all patients (Fig. 4.76).

• However, experience is essential for imaging of patients with complex

congenital heart disease and, in particular, interpretation of imaging can

be operator dependent. Therefore, if you are not experienced do not

hesitate to ask for advice or support from seniors or a specialist Adult

Congenital Heart Disease Centre.

• Beware of endocarditis in the congenital patient.

332

CHAPTER 4 Transthoracic chambers and vessels

Key views and findings

A standard dataset acquisition can be undertaken. However, additionally,

abdominal views from the subcostal window can be very helpful and

therefore 9 key views are recommended to ensure a systematic approach.

It should also be remembered that because of the unusual features of

congenital heart disease it is also important to be opportunistic if good

images appear in unusual positions. The key 9 views are:

1. Abdominal transverse

• Subcostal window with probe marker at ~3 o’clock: provides

information on abdominal situs (liver/stomach) and relationship of

aorta and IVC (right) to the spine.

2. Abdominal longitudinal

• Subcostal window with the probe marker towards head ~12 o’clock:

used to identify the pulsatile aorta and coeliac axis. If the probe is

angled towards the liver it will be possible to identify hepatic veins and

inferior vena cava draining to a right-sided atrium.

3. Parasternal long axis including the inflow and outflow views

• Useful for assessment of right ventricular outflow tract and right

ventricular inflow.

4. Parasternal short axis

• Especially looking for a perimembranous VSD (at 10 o’clock),

LPA/RPA, origins of coronary arteries, mitral valve and LV/RV.

5. Apical 4/3/2 chamber:

• Look for normal off-setting of atrio-ventricular valves (tricuspid should

be more apical). Identify the moderator band at apex of right ventricle

to establish a morphological right ventricle. Assess for any associated

lesions.

6. Apical 5 chamber:

• Detailed assessment of the aorta and valve.

7. Subcostal (epigastric):

• Scan systematically the liver, right atrium, atrial septum, left atrium, and

pulmonary veins entering left atrium.

8. Arch view/suprasternal:

• Neck extension may optimize views. Identify ascending aorta, neck

vessels and PA. Look for any coarctation or PDA.

9. Right parasternal long axis:

May provide further information on aortic valves.

334

CHAPTER 4 Transthoracic chambers and vessels

Sequential segmental analysis

There is some key information that needs to be established in order to

evaluate a patient with congenital heart disease. This information relates to

how the heart and blood vessels connect together. The sequence given here

can be used to gather all this key information (see also Table 4.10).

Establish arrangement of atrial chambers (situs)

The atria are defined by the appendages (right-broad, left-narrow) and

by the systemic and pulmonary connections. Normal is situs solitus and

abnormal situs inversus (morphological left atrium on right). Abdominal

organs usually match atria (liver on left suggests inversus). Use subcostal

views and look for the features:

• Left atrium has long, thin atrial appendage and rounded shape.

• Right atrium has broad, short appendage, and Eustachian valve.

• Identify where inferior vena cava and pulmonary vein connect (vein

inflow does not identify atria as connections vary).

Determine ventricular morphology and arrangement: atrioventricular

(AV) connections

Normally the heart tube folds to the right and heart lies in left chest with

right ventricle anteriorly. If the tube folds to the left the right ventricle

lies on the other side of left ventricle. Atrio-ventricular valves stay with

ventricles. Use the following features to identify the ventricles:

• Identify right ventricle from trabeculations, 3 papillary muscles,

tri-leaflet valve, moderator band, and triangular cavity.

• Left ventricle has smooth surface, 2 papillary muscles, bileaflet valve,

and bullet-shape.

• Establish right ventricle from moderator band and tricuspid valve. Left

ventricle is bullet-shaped and associated with mitral valve.

Determine morphology of great arteries

This identifies arterial transposition and can occur if valves are in ‘right’

position but folding rotates ventricles, or if ventricles are right but arteries

are switched.

• Use parasternal short axis and modified long axis views to identify

pulmonary artery from orientation (heading posteriorly) and

bifurcation. Ascending aorta heads superiorly.

• Use suprasternal views to see if the arch goes to left (normal) or right.

Ventriculoarterial (VA) connections

• Morphology of arterial valves, arterial relations, and infundibular

morphology can be established from parasternal and apical windows.

Assess for any associated intracardiac lesions

• Patients may have >1 lesion. A full data set is required looking for flow

abnormalities and shunts.

Establish cardiac position in the chest and orientation of cardiac apex

• Use subcostal view. The usual arrangement of the heart and body

organs is situs solitus (left-sided heart, left-sided stomach and spleen

and a right-sided liver).

CONGENITAL HEART DISEASE

335

Table 4.10 Sequential segmental analysis used in congenital heart

disease

Abdominal situs

Solitus (liver on right, stomach on Left)

Inversus (liver on left/transverse, stomach on right)

Atrial anatomy and

Solitus (RA on right)

systemic venous

Inversus (RA on left)

connections

Ambiguous/indeterminate

Atrioventricular

2 AV valves

connections

Common AV valve

AV valve atresia

Straddling or overriding AV valve

Morphology of

Right ventricle on right

Ventricles

Right ventricle on left

Univentricular heart

Morphology of

Concordant (normal)

great arteries

Discordant (transposition)

Double outlet (left or right ventricle)

Common outlet (truncus arteriosus)

Single artery atresia

336

CHAPTER 4 Transthoracic chambers and vessels

Congenital defects

Some of the disorders that may be seen during routine echocardiography

include:

Patent ductus arteriosus

Patent ductus arteriosus connects aorta to pulmonary artery and can be

identified as follows:

• Identify the aortic end in descending aorta using a suprasternal view

focusing just distal to left subclavian.

• The pulmonary end empties into left pulmonary artery just to left of

pulmonary trunk and can usually be seen from a modified parasternal

short axis views.

• Colour flow will demonstrate a jet directed the wrong way in the

pulmonary trunk (towards the pulmonary valve).

• Report functional effects of the left-to-right shunt.

Persistent left superior vena cava

A persistent left superior vena cava drains into the coronary sinus. Usually

the right superior vena cava is also present although it is possible only to

have a left superior vena cava. To identify these abnormalities:

• Use an apical 4-chamber view adjusted to cut below the mitral valve.

This will demonstrate the coronary sinus. It is usually dilated.

• Agitated saline contrast injected into a vein in the left arm will opacify

the coronary sinus before the right atrium.

• Then inject agitated saline into a vein in the right arm. If the right

superior vena cava is still present contrast will appear in the right

atrium first, as normal. If the right superior vena cava is absent the

saline will appear in the coronary sinus first.

• There is usually no significant haemodynamic effects but it complicates

pacemaker placement.

Anomalous pulmonary drainage

This describes drainage of pulmonary veins into right atrium. Total drain-

age requires a septal defect for oxygenated blood to reach systemic circu-

lation. In partial drainage 1 or 2 pulmonary veins still drain to left.

• Most easily assessed with TOE.

• Right upper pulmonary vein may drain to right atrium or superior vena

cava.

• Right lower pulmonary vein may connect to inferior vena cava.

• Left pulmonary veins may connect to innominate vein.

338

CHAPTER 4 Transthoracic chambers and vessels

Tetralogy of Fallot

Combination of right ventricle outflow obstruction, ventricular septal

defect, right ventricular hypertrophy, and aorta overriding the septum.

Assessment preoperatively should focus on, and quantify, each aspect.

Double outlet right ventricle

Both aorta and pulmonary artery arise from right ventricle. Ventricular

septal defect allows oxygenated blood to reach systemic circulation.

Persistent truncus arteriosus

Single trunk divides into systemic and pulmonary arteries. Associated with

ventricular septal defect and single valve in trunk.

Hypoplastic left ventricle

Usually involves whole of left heart with disordered valve development

and small left atrium and ventricle.

Single ventricle

Single ventricle with mitral, tricuspid, aortic and pulmonary valves con-

nected. Chamber can be of left or right origin with remnants of other

ventricle seen (Fig. 4.77).

Obstructive congenital disorders

Many congenital defects can be organized, and assessed, according to their

restriction or obstruction to blood flow. They can be demonstrated using

standard 2D imaging and Doppler quantifications.

Right ventricular inflow:

• Ebstein’s anomaly and tricuspid atresia (Fig. 4.78 and b p.122).

Right ventricular outflow:

• Subvalvular—outflow tract (use short axis views).

• Pulmonary valve—pulmonary stenosis (b p.156).

• Supravalvular—pulmonary artery (use short axis views).

Left ventricular inflow:

• Pulmonary veins—stenosis or obstruction. Usually requires

transoesophageal echocardiography to document.

• Atrium—atrial membranes (either across the middle of atrium—cor

triatum or supravalvular).

• Mitral valve—congenital stenosis (b p.101), double inlet valve.

Left ventricular outflow:

• Subvalvular—fibromuscular (wall thickening) or membranous (discrete

membrane present) (use parasternal and apical views).

• Aortic valve—bicuspid valve (b p.134).

• Supravalvular level—membranous or fibromuscular thickening (use

parasternal views).

340

CHAPTER 4 Transthoracic chambers and vessels

Surgical correction of congenital

heart disease

Complete repairs

With effective correction there may be little echocardiographic evidence

of repair. A full systematic study should be used and reports made of any

residual functional effects on valve function, as well as disorders of left

or right ventricle appearance or function. Residual shunts or abnormal

vascular connections should be commented upon.

Shunts (Fig. 4.79)

These were designed to increase blood flow into the pulmonary artery to

improve oxygenation but nowadays full repairs of defects are preferred.

Blalock-Taussig shunt

This shunt connects the subclavian or innominate artery to a branch of

the pulmonary artery. The shunt can be made on the left or right. It can

be seen in suprasternal views and both colour flow mapping and Doppler

assessment can be attempted to identify stenosis or changes in flow.

Glenn shunt

The Glenn shunt (may be bilateral) anastomized the superior vena cava to

the pulmonary artery either completely or to allow two-way flow.

Fontan procedure

This was used to bypass an abnormal right ventricle by directing flow from

the systemic atrium to the pulmonary circulation. In fact there are a range

of Fontan procedures and it can be difficult to evaluate with echocardiog-

raphy without knowing the surgical details although assessing ventricular

343

Chapter 5

Transoesophageal

examination

Introduction 344

Indications

346

Contraindications and complications 348

Information for the patient 350

Preparing for the study 352

Preparing and cleaning the probe 354

Probe movements 356

Anaesthetic, sedation, and analgesia

358

Sedation complications 360

Intubation

362

Image acquisition 364

Four chamber view 368

Five chamber view 370

Short axis (aortic valve) view

372

Short axis (right ventricle) view

374

Long axis (aortic valve) view

376

Long axis (mitral valve) view

378

Atrial septum (bicaval) view 380

Two chamber (atrial appendage) view 382

Pulmonary vein views 384

Coronary sinus view 386

Transgastric short axis views

388

Transgastric long axis view 390

Transgastric long axis (aortic) view

392

Transgastric right ventricular view

394

Deep transgastric view 396

Pulmonary artery view 398

Aortic views 400

3D oesophageal views 402

3D mitral valve 404

3D aortic valve 406

3D aorta 406

3D tricuspid valve 408

3D pulmonary valve 408

3D left ventricle

410

3D interatrial septum 412

X-plane 414

344

CHAPTER 5 Transoesophageal examination

Introduction

• Transoesophageal echocardiography (TOE) has emerged over only

the last 30 years. The first M-mode transoesophageal images were

published in the 1970s by Dr Frazin, a cardiologist in Chicago, who

attached a traditional probe onto the end of an endoscope. It did

not catch on as a technique because the patient found it difficult to

swallow the probe.

• By the early 1980s 2D imaging with superior, smaller probe technology

had become realistic, significantly advanced by the introduction of the

electronic, phased-array probe. The early probes were single plane and

it was not until the 1990s that biplane probes became a reality. These

were finally superseded by multiplane imaging, a move that provided

the leap in functionality that we take for granted today.

• TOE uses all the same technology as transthoracic imaging.

2D echocardiography, colour and spectral Doppler can all be

performed as well as tissue Doppler imaging and 3D reconstructions.

However, transoesophageal imaging possesses a major advantage in

that there is little tissue between the probe and the heart to degrade

the image. This also means the probe virtually touches the heart so the

ultrasound beam does not need to penetrate as far. Higher ultrasound

frequencies can therefore be used (typically 5-7.5MHz) which

enhances spatial resolution.

• A lot of the clinical applications have been driven by interest in

intraoperative monitoring and this remains a key application of the

technique. However, real-time imaging with unparalleled spatial and

temporal resolution makes the image quality superior to all other

modalities within the imaging window provided by the oesophagus.

As the procedure is well tolerated, TOE has guaranteed usefulness

for cardiology studies, particularly where detailed anatomical and

functional imaging is needed.

• During the last few years real-time 3D transoesophageal

echocardiography has become an important tool in particular to guide

interventions.

INTRODUCTION

345

Performing the study

• There are many different patients in whom TOE is requested, from

patients who require elective monitoring of stable clinical problems

such as aortic dissection to those with emergency haemodynamic

problems. The background and approach to each study will

therefore vary considerably. This chapter is written to provide a

framework to perform an elective, or planned, transoesophageal

echocardiogram in an awake patient.

• For intraoperative studies or those on Intensive Care Units the

patient is already sedated or anaesthetized and, unless planned

before an operation, may not have given consent. However, even

in these situations the majority of the framework for performing

a study is still relevant. All aspects of assessing indications and

contraindications should be carried out, as well as preparation of

machine, probe, and monitoring. The only real differences are usually

the patient position (lying on their back), the presence of other

things in the mouth (tracheal tubes), and depth of sedation

(general anaesthetic or deep sedation).

346

CHAPTER 5 Transoesophageal examination

Indications

There are generally accepted, evidence-based uses of TOE which have

evolved in clinical situations where there is a need for high spatial and

temporal resolution to assess pathology.

• Haemodynamic monitoring in anaesthetized patient:

• Perioperative monitoring.

• Intensive care monitoring.

• Evaluation of valve pathology:

• Pre-surgical evaluation for repair of mitral or aortic valves.

• Evaluation of cause of dysfunction.

• Intracardiac shunts.

• Cardiac embolic source:

• Intracardiac shunts.

• Left-sided thrombus—ventricle, left atrial appendage.

• Left-sided valve abnormalities/masses/vegetations.

• Aortic atheroma.

• Endocarditis:

• Diagnosis.

• Monitoring.

• Evaluation of prosthetic valve dysfunction.

• Congenital heart disease.

• Aortic dissection and aortic pathology.

• Cardiac masses (where transthoracic imaging inadequate).

• Imaging during procedures:

• Percutaneous procedures—ASD/PFO closure, mitral balloon

valvuloplasty.

• Electrophysiology and pacing—transseptal puncture, lead

placement.

• Cardiothoracic surgery.1

• Transcatheter aortic valve implantation (TAVI).

• Poor transthoracic windows or inadequate image quality.

Reference

1 American Society of Anesthesiologists. Practice guidelines for perioperative transesophageal

echocardiography. Anesthesiology 1996; 84:986–1006.

348

CHAPTER 5 Transoesophageal examination

Contraindications and complications

Consider contraindications before starting. Absolute contraindications

tend to be oesophageal problems that make the procedure technically

impossible and increase the risk of traumatic injury. The decision to go

ahead despite relative contraindications depends on the importance of

the clinical information to be gathered, whether there are alternative ways

to gather the data and operator experience. During and after the proce-

dure be vigilant for possible complications and ensure the patient is fully

informed of these risks when taking consent.

Absolute contraindications

• Oesophageal tumours causing obstruction of the lumen.

• Oesophageal strictures.

• Oesophageal diverticula.

• Patient not cooperative.

Relative contraindications

• Oesophageal reflux refractory to medical therapy.

• Hiatal hernia.

• Odynophagia or dysphagia.

• Previous oesophageal or gastric surgery.

• Previous oesophageal or gastric bleed.

• Oesophageal varices: using a sheath is said to reduce the risk as the gel

reduces the pressure of the probe tip. However, transgastric views are

not advised and there must not have been a bleed in the preceding

4 weeks.

• Severe cervical arthritis.

• Profound oesophageal distortion.

• Recent radiation to head and neck.

• Significant dental pathology.

Complications

A study of complications in around 10,000 patients showed a very low

incidence.1 Failed intubation occurred in around 2%. All other complications

had an incidence of <1%.

• Intubation problems—termination because of choking.

• Pulmonary problems—bronchospasm, hypoxia.

• Cardiac problems—ventricular extrasystole, tachycardia, atrial

fibrillation, AV block, angina.

• Bleeding—from pharynx, related to vomiting, from oesophagus.

• Perforation—risk of perforation increases in small patients and in all

conditions that make the oesophagus friable, e.g. prior radiation to

head, neck or oesophagus, steroid treatment, gastro-oesophageal

reflux disease, prolonged duration of probe in patient.

• Probe failure.

350

CHAPTER 5 Transoesophageal examination

Information for the patient

For elective or planned studies patients should be provided with informa-

tion or have a detailed verbal explanation. Informed consent is essential as

it is a semi-invasive procedure and sedation is used.

Example information sheet

You have been asked to attend for transoesophageal echocardiography

(TOE). A TOE is a test that allows the doctor to look closely at the

heart without other organs obscuring the view. In order to carry out

the procedure, the scope, which is a long flexible tube, is passed through

the mouth and down the gullet.

Before the procedure

You should not have anything to eat or drink for at least 6 hours before

the procedure. When you arrive you will be seen by a doctor who will

take a medical history and after explaining the procedure, ask you to sign

a consent form. If you have any concerns, please do not hesitate to ask,

as we would like you to be as relaxed as possible. We will be pleased

to answer any queries.

What happens during the procedure?

A blood pressure cuff will be attached to your arm and a small moni-

tor placed on your finger to monitor the oxygen levels in the blood.

The doctor will spray your throat with some local anaesthetic. A mouth

guard is placed between your teeth to protect the tube and your teeth.

You will be asked to turn onto your left side and the room’s main lights

will be turned off. Your sedation is then given through a small tube

(cannula) which will be inserted into your arm. When you are sleepy

the procedure will start. There will be several people looking after you

including the doctor, a nurse and a technician. The procedure takes

10-20min to examine all areas carefully.

Benefits The benefits from TOE are that it can: define the nature of

cardiac symptoms; decide which further therapeutic and diagnostic pro-

cedures you may have to undergo.

Risks

Risks from TOE are tiny. Usually the investigation is tolerated well; some

patients may have some mild symptoms during the test (mostly coughing).

Serious risks are very rare and include palpitations 0.75% (7 patients in

every 1000), angina 0.1% (1 patient in every 1000), bronchospasm/hypoxia

0.8% (8 patients in every 1000), bleeding 0.2% (2 patients in every 1000),

oesophagus perforation, extremely rare less than 0.01% (1 in every

10 000 patients). Your doctor would not recommend that you have a

transoesophageal echocardiogram unless they felt that the benefits of

the procedure outweighed these small risks.

After the procedure The sedation may last up to an hour. Your blood

pressure and respiration will be checked and you may have an oxygen

mask on while you are awake. The sedation has an amnesic effect so you

should remember little of the procedure when you wake up.

352

CHAPTER 5 Transoesophageal examination

Preparing for the study

Setting up the environment

• With the patient on their bed, ensure there is a blood pressure cuff

on the arm and set to automatic monitoring every 5-10min. Check a

baseline blood pressure.

• Set up stable ECG monitor on the machine.

• Monitor oxygen saturations and check a baseline saturation level.

• Provide supplemental oxygen, usually via nasal specs at 2L/min.

• Ensure suction is available and working.

• Check bed height and position so operator and nursing staff are not

bending over the patient but stand upright during the procedure.

• Check relative position of machine, patient, and operator to ensure

operator has a clear view of images.

Nursing

• The nurse should talk to the patient and check identity and consent.

• The nurse stands behind the patient or at the head of the bed to

reassure the patient and support the head and mouth guard.

• During the procedure they should monitor haemodynamics and

saturations and inform the operator if they change.

• They should monitor for secretions and give suction as required.

• After the procedure they should stay with the patient to ensure

adequate recovery from the sedation.

Operator

• Check notes for indications and purpose of study. Check past medical

history, allergies, and any contraindications.

• Make sure patient has been starved for at least 6 hours and has taken

out any false teeth/loose bridges/loose teeth.

• Ensure the apparatus is ready: probe prepared (b p.354), attached,

and selected; probe steering works; transoesophageal machine presets

selected, ECG tracing and patient details on machine.

• Sedation drawn up (b p.358), local anaesthetic spray available, and IV

cannula in arm ready for sedation.

• Ensure gel ready to be applied to probe.

• Then give local anaesthetic spray (b p.358).

• For the awake patient, ask them to roll onto their left side and ensure

a stable position—often achieved if the patient brings their right leg

over their left in a ‘recovery position’ arrangement. If in an ITU setting,

ask if the patient is able to be rolled onto their left.

• Ensure the head of the bed is flat, the patient has their head on a

pillow, and there is a mat under the head to absorb any secretions.

• For the awake patient, ask them to drop their chin onto their chest.

• Place the mouth guard between their teeth.

• Give sedation (b p.358) and start the intubation (b p.362).

PREPARING FOR THE STUDY

353

Preparing for TOE—a 10-point plan

1. Put sheath on the probe.

2. Review referral form/notes for indication, contraindications.

3. Ask patient when was last meal (should be >6 hours before),

previous problems with swallowing, known oesophageal disease,

allergies.

4. Insert patient name and hospital number on scanner and ask

patient to confirm.

5. Insert IV cannula.

6. Attach probe to the scanner, test steering and whether probe is

accepted by the scanner.

7. Start blood pressure monitoring and pulse oximetry, nasal specs

for oxygen supply (2L/min).

8. Apply local anaesthesia to patient’s throat, then rotate patient into

a left lateral decubitus position.

9. Put in mouth guard.

10. Give sedation.

354

CHAPTER 5 Transoesophageal examination

Preparing and cleaning the probe

The probe can easily be damaged either externally (by chemicals or mis-

use) or by the patient (beware teeth!). There are also important health

and safety issues about protecting the patient from the probe.

Checking the probe

Check over the probe at the start of the procedure. Look for evidence

of damage to the coating and layers. There may be breaks or ‘bubbling’

in the coating. In extreme situations the underlying wire shielding may

be exposed with a risk of current leak or heating to the patient. If you

are concerned about the integrity of the probe use a different probe and

contact the manufacturer.

Preparing and cleaning

There are 2 options for probe preparation and cleaning.

The probe is used without a cover

Glutaraladehyde

• In this case it is essential it is sterilized between cases. After the

investigation the probe should be washed down with water and

then immersed in a tube containing glutaraldehyde solution (licensed

for endoscope disinfection) for a fixed period of time according to

manufacturer guidelines.

• Glultaraldehyde can cause allergies or breathing problems. Therefore

ensure regular fresh air in the room where the probe is cleaned.

Furthermore, the probe needs to be rewashed with water to ensure

the solution is removed before the probe is used on the next patient.

• The handgrips and controls of the probe should be wiped with an

alcohol-based agent. Alcohol should not normally be used to clean the

transducer face at the tip of the probe.

The probe is used with a purpose-designed sheath

• Sheaths protect the probe from infection and provide electrical

isolation from the patient.

• There are both latex and latex-free versions.

• To prepare, fill the sheath tip with the supplied gel using a syringe.

• Then feed the probe all the way into the sheath and fix the upper end

with the supplied plastic clip.

• Avoid air bubbles in the gel around the transducer as these degrade

image quality. Press them further up the sheath or pull and release the

sheath tip to expel them away from the transducer.

• When performing a series of studies there is no need to carry out

a complete disinfection between patients. After each investigation

remove the sheath and wipe off any gel left on the probe. Then clean

the probe with water and an alcohol-based agent.

• If the sheath breaks during the procedure or a perforation is seen

afterwards, immerse the probe in disinfectant solution.

• In patients with a high infection risk (HIV, hepatitis B, etc.) disinfect the

probe with a commercial solution after sheath removal and sterilize

the controls with alcohol-based solutions.

PREPARING AND CLEANING THE PROBE

355

Tristel sporicidal wipe

• This is a rapid action sporicidal wipe (Fig. 5.1) which is used to clean

probes that have been used with sheaths.

• After removing the sheath, the first step is to clean the probe with

the pre-clean sporicidal wipe. It is impregnated with a low-foaming

surfactant system combined with triple enzymes, producing ultra-low

surface tension for rapid cleaning.

• Then apply the sporicidal wipe which is initially activated with a foam

pump.

• Next, application of the rinse wipe is the final step in the

decontamination process. It is impregnated with deionized water and

a low level of antioxidant which will remove and neutralize chemical

residues from the probe surface.

Fig. 5.1 Tristel sporicidal wipes. Following the procedure the probe is initially

cleaned with the pre-clean wipe. The sporicidal wipe is then activated with a foam

pump and used to clean the probe. Finally the rinse wipe is used to wipe the probe,

neutralizing any remaining chemical residues.

356

CHAPTER 5 Transoesophageal examination

Probe movements

A combination of probe movements is required to gather all the images

(Fig. 5.2). For many of the views, changes in sector angle are the primary

control, with physical movements used to optimize the image.

Withdrawal and advance

Moving the probe forward and backwards in the oesophagus is the sim-

plest manoeuvre. The depth of the probe is best controlled with the hand

nearest the patient’s mouth. This hand can also judge the size of small

movements forward and back relative to the mouth guard. The depth

of probe insertion is marked on the probe in centimetres. This number

should be used when images need to be annotated to record probe depth.

It measures the distance from probe tip to front incisors.

Rotation (or turning)

The probe can be rotated clockwise or anti-clockwise within the oesopha-

gus. This is achieved by twisting the handheld control section with one

hand, and the probe near the mouth guard with your other hand. This

movement is usually used to orientate the heart in the image plane and to

look at the descending aorta.

Sector angle

On the controls there are usually 2 buttons side by side. These rotate the

angle of the imaging plane forward and backward between 0° and 180°.

The angle plane can also sometimes be changed directly from the ultra-

sound machine. The current angle plane is displayed on the screen.

Angulation (or retro-/ante-flexion)

The large wheel on the control panel moves a few centimetres of the

transducer tip forwards and backwards. Angulation forwards is usually

used to press the transducer against the oesophagus wall or stomach to

improve contact and image quality. Angulation backwards can be effective

at lengthening out the left ventricle.

Lateral motion

The small wheel on the control panel causes movement of the transducer

tip from side-to-side. This is very rarely used and for the most part can

be ignored. Occasionally with difficult images or abnormally positioned

hearts small lateral motions may be helpful.

Position lock

Most probes have a lever behind the control wheels that locks the probe in

position. For most studies this is not required and can be ignored. For long

periods of monitoring—particularly in transgastric views intraoperatively—

the lock can be used. However, there is an increased risk of traumatic

injury with movement of the probe with the lock on. Care must be taken

to remove the lock before the probe is repositioned.

358

CHAPTER 5 Transoesophageal examination

Anaesthetic, sedation, and analgesia

Local anaesthetic

• Start with a local anaesthetic Xylocaine® (lignocaine) spray.

• With the patient sitting up, spray several times onto the back of

their throat. Ask them to hold the liquid for a few seconds and then

swallow. Repeat the spray to ensure good anaesthesia.

• Warn the patient that the spray has an unusual taste, their mouth and

throat will feel numb, and their swallow may feel strange or difficult.

• The spray will need 2-3min to have an effect.

Sedation and analgesia

There are no standard guidelines for TOE and it is possible to perform the

study with no sedation. However, the following routines (see also Fig. 5.3)

can be used (borrowed from other endoscopic procedures). A benzodi-

azepine provides sedation and amnesia, and an opioid analgesia. Remember

that ‘the difference between good and bad sedation is around three minutes’,

i.e. wait for the sedation to work.

• Ensure reversal agents are available and accessible (flumazenil for

midazolam and naloxone for pethidine or fentanyl). Life support

equipment should be accessible.

• Start with 25microgram IV fentanyl (or 25mg IV pethidine)—then

give 2mg IV midazolam and this is usually sufficient for most patients.

Aim for the patient to be ‘drowsy but rousable’. In certain patients

and situations lower starting doses are advisable (see b ‘Specific

situations’ p.358).

• Wait 3-5min then assess level of sedation (patient response,

haemodynamics). If not adequate, give further bolus of 2mg IV

midazolam.

• Repeat the ‘wait and bolus’ regime until adequate sedation.

• Total sedation should not exceed 10mg midazolam and/or 75mg

pethidine (or 100microgram fentanyl). Stop and consider a general

anaesthetic at a later date.

• Once sedation is appropriate start intubation. If intubation is difficult

because the patient is awake return to the sedation routine.

• During the procedure (after intubation) if the patient becomes

distressed consider giving further boluses of sedation.

Specific situations

• In younger patients (and some older patients) increasing doses

of midazolam can increase agitation and be counterproductive.

Consider using more analgesia and less sedation from the outset.

• In older patients (particularly >80 years) oversedation is a problem

so start with 1mg IV midazolam, withhold the opioid, and wait longer

between boluses as the sedation may be slower to circulate.

• Use lower starting doses for those with significant left ventricular

failure or respiratory disease, hypotension, or neurological

impairment.

ANAESTHETIC, SEDATION, AND ANALGESIA

359

Patient assessment (allergies, IV access,

consent).

BP, ECG and oxygen monitoring.

Supplemental oxygen.

Equipment prepared.

Sedation drawn up and antidotes present.

Local anaesthetic throat spray

Give 25microgram fentanyl (or pethidine 25mg)

Give 2mg midazolam

(1mg if >75 yrs or depressed respiratory, cardiac or

neurological function)

Wait 3 to 5

minutes

YES

Assess sedation level (aim for drowsy but rousable)

Less than 10mg

Adequate

midazolam given?

sedation?

YES

Continue with intubation and/or

investigation

Stop and

consider

alternative

approaches

Adequate

Stop and reverse

sedation for

agents

intubation?

YES

Adequate

YES

Oversedated

sedation during

haemodynamic

procedure?

problems, not

rousable?

End of

procedure

YES

Post procedure

care

Fig. 5.3 Flow chart for sedation protocol.

360

CHAPTER 5 Transoesophageal examination

Sedation complications

Although by using low-dose conscious sedation with up-titration com-

plications are relatively infrequent, it is always essential to be vigilant.

Monitoring of the patient during the procedure is mandatory. Several

expert bodies have produced guidelines for how to give sedation if you

are not an anaesthetist. It is advisable to have a local policy for how to use

sedation for TOE and an audit process so that problems or adverse events

associated with the procedure are identified.

Peri-procedure

• Monitor for drops in blood pressure and saturations throughout the

procedure. These are the commonest side effects of sedation.

• If hypotensive, patients may be mildly dehydrated as they are nil by

mouth so consider IV fluids.

• Drops in saturations may be temporary at the start of sedation and

can be corrected with increased supplemental oxygen.

• If there are ever any concerns about the level of sedation or degree of

haemodynamic or respiratory changes, reverse the sedation and stop

the procedure (if still ongoing).

• To reverse the midazolam give flumazenil. This is relatively short acting

so after a period of time, if the sedative effects return, consider further

boluses or even an infusion.

• To reverse the opioid give naloxone.

• In those with left ventricular failure, lying flat with sedation can

precipitate acute failure so be alert for clinical signs and treat with

diuretics etc. if necessary.

• Allergic reactions can occur with sedation so treat as appropriate.

Post-procedure

• After the procedure, the patient should be monitored until they are

fully awake.

• If the procedure has been elective and the patient is going home

afterwards they should be advised not to drive or operate heavy

machinery for 24 hours.

Further reading

Mankia K et al. Safe combined intravenous opiate/benzodiazepine sedation for transoesophageal

echocardiography. Br J Cardiol 2010; 17:125–7.

362

CHAPTER 5 Transoesophageal examination

Intubation

Intubation is a key skill to learn. Unless you intubate successfully the pro-

cedure can not start. The skills to perform successful intubation in elective

studies with light sedation are broadly similar to those skills for intubation

in intraoperative or Intensive Care settings. Everyone develops their own

techniques but a standard procedure is as follows.

Intubation with light sedation

General

• Ideally have two people, one to hold the controls, and the other to

hold the end of the probe and intubate. If on your own, lie the probe

along the bed and concentrate on intubation. Some people can hold

the controls in one hand and feed the probe with the other, but this

requires an uncomplicated passage of the probe.

• Talk confidently and calmly to the patient. Guide them through the

procedure and the swallows. After intubation reassure them and

tell them to take gentle breaths through the nose. The attitude of

the operator and how they relate to—and relax—the patient often

determines the success of the procedure.

The routine

• The patient should be lying on their left side with their chin towards

their chest. This encourages the probe to pass into the oesophagus

(exactly what you try to avoid with chin-lift during resuscitation).

• Check the mouth guard is in position between the teeth.

• Wipe gel over the probe tip to about 40cm. Too much increases the

risk of aspiration and too little makes probe movement difficult and

uncomfortable for the patient.

• Check probe controls and put a curve on the end of the probe.

• Ensure the curve on the tip lines up with the expected curve into the

back of the mouth then pass the probe through the mouth guard and

onto the tongue.

• Ask the patient to swallow once to get the probe to the back of the

mouth and then a second time to pass it into the oesophagus. The

second step should be timed to coincide with the swallow.

• To direct the probe a finger can be placed in the mouth beside the

mouth guard. This guides the probe into the back of the mouth. It

is especially useful when learning, when the probe is not passing

smoothly, or in the anaesthetized patient.

• When the probe is in the oesophagus stop and do not move anything

for a few minutes while the patient settles.

• The operator should then remove one glove and get into position.

One gloved hand controls the probe at the mouth guard and the other

holds the controls. The operator usually stands facing the patient with

their right hand at the patient’s mouth and looks over their shoulder at

the images. An alternative arrangement is to stand at right angles, with

the left hand at the patient’s mouth, facing the machine.

INTUBATION

363

Intubation in the anaesthetized patient

• Use the same probe preparation and use a mouth guard.

• Ensure there is a curve on the probe, then use a finger to guide the tip

into the back of the mouth.

• If the patient is on their back get someone to lift the chin towards the

chest.

• The probe may pass smoothly into the oesophagus with light pressure.

If there is resistance induce a reflex swallow with some forward

pressure on the back of the tongue.

• If a tracheal tube is in place, passage of the probe into the oesophagus

may be restricted by the tracheal tube. To overcome this, ask for the

assistance of the anaesthetist, either to temporarily deflate the cuff or

to manipulate the tracheal tube.

What to do if the probe does not pass or patient is

agitated?

• You should not need to give more than a gentle steady force to the

probe. If resistance is felt assume it has gone the wrong way.

• If you are not already using your finger to guide the probe, do so.

• Feel where the tip of the probe has gone. It may have doubled

back on itself in the mouth or you may feel it heading up or down.

Withdraw slightly, adjust the rotation and then try to advance again,

with a swallow.

• If it is not clear where the probe has gone, withdraw entirely, check

the curve on the probe and its direction, then restart.

• If the patient cannot swallow because they are too sedated use a

finger to direct the probe.

• If the patient starts coughing think whether you may have passed the

probe into the trachea. Withdraw the probe and start again.

• If the patient becomes very agitated, stop and consider whether to

try again after more sedation and/or analgesia.

• In around 2% of cases intubation fails. Know when to stop. After two

or three attempts have been unsuccessful consider getting help from

a more experienced operator, if available. If the patient is becoming

very agitated despite adequate sedation and analgesia, stop. If

the investigation is essential, the study can always be rearranged

with a general anaesthetic to ensure patient compliance and/or an

anaesthetist to aid intubation.

IMAGE ACQUISITION

365

Optimize the views using small changes in transducer

position

Adjust by angulation, moving the transducer up and down, and rotating

the sector (tips will be given for each of the views). Don’t move too fast

and too much. Slight changes have a big impact on the image!

Most scan planes have several different structures

All structures cannot always be viewed in a single recorded loop. Slight

adjustments of the probe position and/or sector may be needed and

loops recorded for each structure.

If you get lost

If during a transoesophageal investigation you become disoriented find

the 4-chamber view again. Reset the rotation to 0° and then try some

rotation and repositioning of the probe until the 4 chambers come back

into view.

366

CHAPTER 5 Transoesophageal examination

The ‘screenwiper’ principle

The best initial sequence of views (scan planes) is summarized by the

screenwiper principle (Fig. 5.4). This section describes how to collect tran-

soesophageal data following the screenwiper principle.

• Starting from 0° the sector is moved across in steps to around 135°

and then back again in a series of steps.

• At each step the view needs only minor modifications of probe

position to optimize the image. This reduces major probe movements

and minimizes patient discomfort.

Each view is examined in:

• 2D imaging.

• Then colour flow Doppler recordings.

• And, if needed, spectral Doppler recordings (PW and/or CW).

3D imaging allows the acquisition of real-time 3D information about car-

diac structures and improves spatial orientation. 3D can be performed

in selected views for example of the mitral valve. As with transthoracic

echocardiography, a variety of acquisition modes can be used depending

on the size of the volume of interest.

• Live 3D acquisition: allows the generation of live 3D images

which are displayed in a pyramidal volume without the need for

electrocardiographic gating.

• Live 3D zoom: allows the display of a magnified pyramidal volume

(smaller than live 3D mode).

• Full volume acquisition: allows the segmental build up of a 3D image

over several consecutive cardiac cycles and gives the largest volume

images.

• 3D full volume colour acquisition.

• X-plane imaging: this provides 2 orthogonal views from the same heart

beat. The initial image on the left is the baseline reference whilst the

image on the right can be electronically rotated to any angle between

0-180°.

After the screenwiper is complete, additional views can then be used, as

required, to look at pulmonary veins, transgastric views, the aorta, or any

abnormal findings.

IMAGE ACQUISITION

367

4 chamber

view

0º

5 chamber

view

50º

Short axis

Long axis

135º

aortic view

75º

aortic view

110º

2 chamber

Bicaval

view

Fig. 5.4 ‘Screenwiper’ principle showing sequence of sector angles for first 6 views.

Once in position, the image can be optimized with slight variation in sector angle

(usually <5°) followed by slight adjustments in depth and tilting as necessary.

Basic screenwiper study

4-chamber view.

5-chamber view.

3. Short axis aortic view (± right ventricle inflow/outflow).

4. Long axis aortic view.

5. Interatrial septal view.

6. Left atrial appendage view.

then further views

7. Left pulmonary venous view.

8. Right pulmonary venous view.

9. Pulmonary artery view.

10. Transgastric views.*

11. Descending aorta view.

12. Aortic arch view.

^* Not necessary in all patients.

368

CHAPTER 5 Transoesophageal examination

Four chamber view

This is the first view to acquire (Fig. 5.5) and is similar to the transthoracic

4-chamber view (but upside down). After intubation, advance the probe

to around 35cm from the teeth.

Finding the view

• Rotation should be set at 0°.

• The atria will probably be the first feature you see.

• Turn the probe to swing all 4 chambers into view.

• Withdraw and advance the probe slightly to avoid the LVOT but keep

a clear view of the mitral valve.

• If the LVOT is still seen, try adding up to 15°.

• If necessary, improve contact by probe angulation.

What do you see?

Use this view to assess

• Global and regional left ventricle function, and wall thickness.

• Right ventricle size and function.

• Mitral valve morphology (orifice, prolapse).

• Tricuspid valve morphology.

Use this view to measure

• Right and left ventricle size (although beware foreshortening).

• Mitral Doppler measurements.

Key features of view

• Mitral valve: key view for mitral valve to assess morphology and

haemodynamics. A2 segment of anterior mitral leaflet (aML) and

P3 segment of the posterior mitral leaflet (pML) seen. Colour flow

mapping will show stenosis and/or regurgitation. Supplement with CW

or PW Doppler as for transthoracic echocardiography.

• Tricuspid valve: lateral leaflet is better displayed than septal.

Assessment is often limited by foreshortening. To get a better view

of the tricuspid valve advance the probe slightly deeper into the

oesophagus. Supplement with Doppler as required.

• Left and right atrium: the main cavity of both atria and the interatrial

septum can be seen. However, fossa ovalis is not usually seen. Turn

the probe slightly left and right to scan through the atria.

• Left ventricle: parts of the interventricular septum and the lateral wall

are displayed. Often left ventricle is foreshortened and measurement

of end-diastolic and end-systolic volumes may be inaccurate. Retroflex

the probe to lengthen out the left ventricle but beware contact may

be lost.

• Right ventricle: an impression of size and function of the right

ventricle relative to the left is obtained, although there is a risk of

foreshortening, as with the left ventricle.

370

CHAPTER 5 Transoesophageal examination

Five chamber view

This is the second view and is similar to the transthoracic apical 5-chamber

view (Fig. 5.6). The main purpose is to get to the appropriate level for the

aortic short axis view. However, an initial view of the LVOT is provided.

Finding the view

• Rotation should be set at 0°.

• From the 4-chamber view withdraw the probe very slightly until the

LVOT comes into plane.

What do you see?

Use this view to assess

• LVOT obstruction.

• Aortic regurgitation.

Use this view to measure

• No specific measurements.

Key features of view

• Most of the features are as for the 4-chamber view.

• LVOT: look at the size of the outflow tract and use colour flow

mapping within the tract to look for aortic regurgitation or flow

turbulence due to obstruction.

372

CHAPTER 5 Transoesophageal examination

Short axis (aortic valve) view

An essential view. The perfect short axis view of the aortic valve, it

can also provide information on the right heart and interatrial septum

(Fig. 5.7). It is equivalent to the parasternal short axis.

Finding the view

• From the apical 5-chamber rotate the sector to around 50°.

• Optimize further with slight clockwise rotation of the probe.

• The probe may need to be withdrawn or advanced slightly to get the

right scan plane. Focus on a clear view of the aortic valve.

What do you see?

Use this view to assess

• Aortic valve morphology and pathology.

• Perivalvular processes.

• Sometimes, tricuspid and pulmonary valves.

• Coronary artery origins can also be seen.

• Interatrial septum for patent foramen ovale.

Use this view to measure

• Left atrial diameter.

• Aortic valve orifice area and aortic root diameter.

Key features of view

• Aortic valve: the valve lies in the centre: left coronary cusp on the

right, right coronary cusp at the bottom and non-coronary on the left.

Colour flow identifies regurgitation and, by adjusting the image to go

through the tips of valve, planimetry can be used to measure aortic

valve orifice area.

• Aortic root: around the valve is the aortic root. Infection or aortic

surgery can make this thickened or ‘boggy’. Abscesses may also be

seen.

• Transverse sinus: between the aortic root and the left atrium is the

transverse sinus (part of the pericardial space). This may contain fluid.

• Coronary arteries: to display the coronary ostia withdraw the probe

a few millimetres. Left main stem is at 2 o’clock and right coronary

artery at 6 o’clock. The left coronary system can sometimes be

tracked to, and beyond, the bifurcation. Colour flow and Doppler

demonstrates flow.

• Left atrium: lying between the probe and the aortic valve, this is a

standard view for linear measures of left atrial size.

• Tricuspid valve: this can sometimes be seen below and to the left of

the aortic valve. Better views are obtained from the right ventricular

inflow/outflow view.

• Pulmonary valve: this lies below and to the right of the aortic valve.

• Interatrial septum: the interatrial septum abuts the aortic root in the

10 o’clock position. The fossa ovalis is not usually seen but when

looking for a patent foramen ovale this view is often very stable for

shunt studies using colour flow or contrast.

374

CHAPTER 5 Transoesophageal examination

Short axis (right ventricle) view

This view may be included for better display of the pulmonary valve and is

also called the right ventricle inflow-outflow view (Fig. 5.8).

It is very similar to the aortic view and can be skipped if the pulmonary

valve has already been adequately displayed. It is equivalent to the par-

asternal short axis transthoracic view.

Finding the view

• From the short axis aortic view rotate the sector to around 70-80°.

• The probe may need to be withdrawn or advanced slightly to get the

right scan plane. Focus on a clear view of the pulmonary valve.

• The optimal view will include the tricuspid and pulmonary valve with

the right ventricle wrapped around the aortic valve—a right ventricular

inflow-outflow view.

What do you see?

Use this view to assess

• Pulmonary valve morphology and pathology.

• Tricuspid valve morphology and pathology.

• Base of right ventricle.

Use this view to measure

• Right ventricle and outflow tract size.

Key features of view

• Pulmonary valve: this lies below and to the right of the aortic valve. Use

colour flow to assess for regurgitation.

• Tricuspid valve: lies below and to the left of the aortic valve. Use colour

flow to assess regurgitation and sometimes the valve is sufficiently

aligned for CW Doppler measures.

• Right ventricle: the ventricle wraps around below the aortic valve

and measurements of size at the base and in the outflow tract are

sometimes possible.

376

CHAPTER 5 Transoesophageal examination

Long axis (aortic valve) view

This view is equivalent to a transthoracic apical 3-chamber view or par-

asternal long axis view (Fig. 5.9). It is used to assess the aortic and mitral

valves as well as left ventricle, outflow tract, and left atrium. In some peo-

ple the mitral valve is not seen well as it lies more inferiorly. An adjusted

long axis view will then be needed to assess the mitral valve (b p.418).

Finding the view

• From the short axis views rotate the sector to around 135°.

• Withdraw, advance, and turn the probe slightly to get the scan plane.

• Focus on a clear view of the aortic valve and ascending aorta.

• The optimal view will include 2 clear valve leaflets and a straight

ascending aorta.

What do you see?

Use this view to assess

• Aortic valve morphology and pathology.

• Mitral valve morphology and pathology.

• Perivalvular processes.

• LVOT and membranous septum.

• Ascending aorta.

Use this view to measure

• Aortic root, sinuses, and ascending aorta.

• Left atrial size.

Key features of view

• Aortic valve: the right coronary cusp is seen at the bottom and non-

coronary cusp at the top. Colour flow will demonstrate regurgitation

and this can be a good view for identifying vegetations or masses.

• Aortic root: the entire aortic root, including sinuses of Valsalva,

sinotubular junction, and ascending aorta should be visible for

measurement.

• Ascending aorta: slight adjustment can often bring into view a lot of the

proximal portion of the ascending aorta.

• Mitral valve: A2 and P2 segments of the valve are seen and can be used

for colour flow and other Doppler measures. However, for proper

visualization the probe may need to be advanced slightly.

• Left atrium: the atrium lies nearest the probe and linear size can be

measured from probe to aortic root.

• Left ventricle: the septum (including the membranous septum below

the aortic valve) and inferolateral wall can usually be seen to assess

wall motion abnormalities.

• Right ventricle: the right ventricle outflow is just seen below the aortic

valve and sometimes the pulmonary valve is partially visible.

• Transverse sinus: This lies between aortic root and left atrium and may

contain fluid.

378

CHAPTER 5 Transoesophageal examination

Long axis (mitral valve) view

This view is a slight adjustment of the long axis aortic view but focused on

the mitral valve. If the views of the mitral valve were already optimal in the

aortic long axis image this view can be skipped.

Finding the view

• From the long axis aortic view, at around 135°, advance the probe

slightly.

• Focus on a clear view of the mitral valve and try and get an

unforeshortened left ventricle.

• The optimal view will include 2 clear mitral valve leaflets.

What do you see?

Use this view to assess

• Mitral valve morphology and pathology.

• Left ventricular global and regional function.

Use view to measure

• Doppler measures of mitral regurgitation and stenosis.

Key features of view

• The features are similar to the long axis aortic view (except the aortic

valve may be less clear).

• Mitral valve: A2 and P2 segments of the valve are seen. Colour

flow can map regurgitation and assess flow convergence and vena

contracta. The valve is also usually aligned for Doppler measures.

380

CHAPTER 5 Transoesophageal examination

Atrial septum (bicaval) view

This is a unique transoesophageal view with no equivalent transthoracic

image (Fig. 5.10). It is perfect for studying both atria and the septum.

Finding the view

• From the long axis views rotate the sector to around 110°.

• Turn the probe clockwise away from the left ventricle. You will see

the septum come into view as a line across the screen.

• Withdraw, advance and turn the probe. Focus on a clear view of the

septum, with the ‘dip’ of the fossa ovalis in the centre.

• The optimal view includes inferior and superior vena cavae on either

side with the right atrial appendage visible on the right.

What do you see?

Use this view to assess

• Drainage of superior and inferior vena cava.

• Assessment for atrial septal defect and patent foramen ovale.

• Drainage of right upper pulmonary vein.

• Eustachian valve.

Use this view to measure

• The tricuspid regurgitation jet may be aligned for Doppler measures.

• A slightly adjusted view can be used to look at the right upper

pulmonary vein flow.

Key features of view

• Left and right atria: the left atrium is nearest the probe.

• Interatrial septum: this is the most prominent feature and can be

qualitatively assessed for thickness and atrial septal defects. Colour

flow mapping and contrast provide more detailed information on

interatrial shunts.

• Inferior vena cava and Eustachian valve: these lie on the left of the

image and flow can be mapped with colour flow. The Eustachian valve

is seen as a mobile strand originating from the orifice of the inferior

vena cava.

• Superior vena cava and christa terminalis: these lie on the right of the

image with the christa terminalis usually seen as a bright bar below the

superior vena cava separating it from the right atrial appendage.

• Right atrial appendage: this is a wide-mouthed, shallow, trabeculated

appendage lying on the right of the image below the superior vena

cava. Atrial pacing wires may be seen hooking into the appendage.

• Tricuspid valve: the tricuspid valve may be seen in the far field. To

optimize the valve image advance the probe. Colour flow can assess

regurgitation and the valve is often aligned for Doppler measures.

• Right upper pulmonary vein: to see the vein the probe needs to be

turned anticlockwise slightly to focus on the superior vena cava. The

right upper pulmonary vein lies parallel to the superior vena cava. The

vein is often aligned for Doppler measures. This view is used to look

for abnormal pulmonary venous drainage.

382

CHAPTER 5 Transoesophageal examination

Two chamber (atrial appendage) view

This view is important for several features of the left heart: mitral valve,

left ventricular function and left atrial appendage (Fig. 5.11). The view is

equivalent to the transthoracic apical 2-chamber view.

Finding the view

• Rotate back from the bicaval view to see mitral valve and left ventricle.

• Change the sector to around 75°.

• Withdraw and advance the probe to focus on a clear view of the

mitral valve and left ventricle. Turn the probe to obtain the longest

(unforeshortened) view of the left ventricle.

• To see the left atrial appendage clearly you may need to adjust the

sector angle between 90° and 50°.

• The optimal view includes mitral valve, left atrial appendage, and an

unforeshortened left ventricle. An unforeshortened left ventricle and

left atrial appendage may not be visible in the same view and in this

case separate images should be stored for each feature.

What do you see?

Use this view to assess

• Global and regional left ventricle function, wall thickness.

• Mitral valve morphology (orifice, prolapse).

• Left atrial appendage.

• Left upper pulmonary vein.

Use this view to measure

• Left ventricle diastolic and systolic dimensions.

• Ejection fraction.

• Mitral valve.

Key features of view

• Left ventricle: the inferior wall is on the left and anterior wall on the

right. This is the preferred view for measurement of left ventricle

size because the ventricle is less likely to be foreshortened with the

sector at 70-90° (the plane can be made to cut through the apex by

turning the probe). Regional abnormalities and papillary muscles can

be assessed.

• Mitral valve: often a commissural view i.e. valve is cut along its

commissure so that P1, A2, and P3 segments are seen. Colour flow and

Doppler measures are possible. Long axis of valve ring can be assessed.

• Left atrial appendage: a curved finger heading down from the left

atrium to the left of the mitral valve. Beware of variation in anatomy,

multiple lobes or retroverted appendages. These will need assessment

with atypical scan planes. Get an optimal image will slight variation in

sector angle and probe position. The appendage is aligned for Doppler

measures.

• Left upper pulmonary vein and ‘warfarin’ ridge: this lies above the left

atrial appendage and is divided from it by the warfarin (or coumadin)

ridge (seen as a bright bar on the right of the screen). Probe may

need to be withdrawn slightly to view vein. Vein is aligned for Doppler

measures.

384

CHAPTER 5 Transoesophageal examination

Pulmonary vein views

Each pulmonary vein requires a separate view (Fig. 5.12).

Finding the views

Right upper pulmonary vein

• The right upper pulmonary vein is best seen in the adjusted atrial

septal (bicaval) view (b p.380) lying parallel to the superior vena cava.

This view also allows Doppler alignment.

• The vein can be identified starting from the apical 4-chamber 0° view.

Rotate the probe to the right hand side of the image and withdraw

slightly. The right upper pulmonary vein is seen adjacent to, and

wrapping around, the superior vena cava. Varying the sector angle may

between 0-20° can be useful to lengthen out the vein.

Right lower pulmonary vein

• The right lower pulmonary vein is best identified starting from the

apical 4-chamber 0° view. Rotate the probe to focus on the right hand

side of the image (as when finding the right upper pulmonary vein) and

then advance the probe slightly. The vein should be seen just below

the right upper pulmonary vein.

Left upper pulmonary vein

• The left upper pulmonary vein is best seen in the adjusted 2-chamber

view (b p.382) lying parallel to, and above, the left atrial appendage.

This view also allows Doppler alignment.

• The vein is also seen with sector set to 0°. Rotate the probe to focus

on the left hand side of the image and withdraw slightly. Look for the

vein orifice.

Left lower pulmonary vein

• To identify the left lower pulmonary vein start from the apical

4-chamber 0° view. Rotate the probe to focus on the left hand side of

the image. The vein should be seen below the left upper pulmonary

vein orifice.

What do you see?

Use these views to assess

• All 4 pulmonary veins.

Use these views to measure

• Pulmonary vein flow in upper pulmonary veins.

Identifying pulmonary veins

• At 0° the lower veins lie roughly perpendicular to the ultrasound

beam (across the screen) while the upper veins lie parallel with the

beam (pointing towards the probe).

• As the names suggest, the lower veins lie below the upper veins. If

an upper vein is identified then advance the probe slightly to see the

lower vein and vice versa.

• Colour flow mapping is very useful to identify the veins. The colour

flow will demonstrate blood flow out of the veins into the atrium.

388

CHAPTER 5 Transoesophageal examination

Transgastric short axis views

Transgastric scanning can be quite uncomfortable to the conscious and

mildly sedated patient. Transgastric views should be performed in well-

sedated, compliant patients when further information is required. They can

also be routinely performed intraoperatively. Short axis views are equiva-

lent to transthoracic parasternal short axis views and can often be adjusted

to create mid-papillary and mitral valve level views (Fig. 5.14). They can be

particularly useful intraoperatively to monitor left ventricle function.

Finding the view

• From the 4-chamber view, with sector angle at 0°, advance the probe

several centimetres. The patient may rouse slightly as you enter the

stomach.

• Angulate the probe forwards hard to try and get it at right angles.

• Withdraw the probe so the transducer tip presses on the upper

stomach wall, against the diaphragm, underneath the heart.

• Make slight adjustments by turning the probe, as well as withdrawing

and advancing until the left ventricle is seen in short axis.

• Keep the probe angulated forward.

• By withdrawing and advancing the probe along the bottom of the heart

it is theoretically possible to see the left ventricle at several levels,

e.g. mid-papillary, mitral valve.

• The optimal view is an on-axis cross-section through the left ventricle.

What do you see?

Use this view to assess

• Global and regional left ventricle function, wall thickness.

• Mitral valve morphology.

• Can provide information on right ventricle size and function.

• Pericardial effusions may be seen.

Use this view to measure

• Left ventricle size and wall thickness.

Key features of view

• Left ventricle (mid-papillary level): with a clear short axis cut through

the ventricle the septum, anterior, lateral, and inferior walls of the

ventricle can be reviewed. This is an ideal view for measures of left

ventricle size and thickness.

• Mitral valve (mitral valve level): a slight withdrawal of the probe from

the mid-papillary level should bring the image plane up to the mitral

valve. You should be able to scan through the chordae up to the

leaflet tips. Use colour flow to highlight regurgitation jets.

• Right ventricle: the right ventricle can be seen as a crescent around

one side of the left ventricle. This view can give an impression of right

ventricle size and function.

390

CHAPTER 5 Transoesophageal examination

Transgastric long axis view

The long axis view provides an unparalleled view of the mitral subvalvular

apparatus (Fig. 5.15).

Finding the view

• From the short view rotate the sector angle to 90°.

• Keep hard probe angulation.

• Make slight adjustments by turning the probe until the left ventricle is

seen in long axis.

• The optimal view should include the mitral valve, subvalvular

apparatus, and left ventricle.

What do you see?

Use this view to assess

• Global and regional left ventricle function, wall thickness.

• Mitral valve morphology.

• Subvalvular mitral apparatus.

Use this view to measure

• Left ventricle size and wall thickness.

Key features of view

• Left ventricle: similar to the 2-chamber view the inferior wall is nearest

the probe and anterior walls in the far field. Foreshortening occurs

easily. This can provide information on wall thickness as well as global

and regional function.

• Mitral valve and subvalvular apparatus: a commissural view, the leaflet

anatomy is not always clear but the subvalvular apparatus can be

incredibly detailed. The different order chordae tendinae as well

as both papillary muscles can be reviewed. Colour flow can map

regurgitation.

• Left atrium and left atrial appendage: the left atrium is present but not

usually in great detail. You may notice the left atrial appendage in the

far field.

392

CHAPTER 5 Transoesophageal examination

Transgastric long axis (aortic) view

The long axis view can be modified slightly to bring the LVOT into the

image for Doppler measures across the aortic valve (Fig. 5.16).

Finding the view

• From the long axis view rotate the sector angle to 110°.

• Keep hard probe angulation.

• Make slight adjustments by turning the probe until the LVOT is seen in

the far field. Colour flow may help to identify flow through the aortic

valve.

• The optimal view should include the LVOT aligned in the far field

aligned for Doppler measures.

What do you see?

Use this view to assess

• Doppler measures of aortic valve velocities.

Use this view to measure

• Aortic and LVOT velocities.

Key features of view

• Aortic valve and LVOT: the aortic valve may be seen close to the

mitral valve in the far field. Colour flow mapping may make this

more apparent. The valve and outflow tract is aligned in this view for

Doppler measures.

394

CHAPTER 5 Transoesophageal examination

Transgastric right ventricular view

This is similar to the left ventricular long axis view but can be difficult

to find. However, if available it can give a useful assessment of the right

ventricle and inflow (Fig. 5.17).

Finding the view

• From the transgastric long axis left ventricle view turn the probe

clockwise.

• The right ventricle should appear in long axis similar to the left

ventricle.

• The optimal view should include the tricuspid valve, subvalvular

apparatus, and right ventricle.

What do you see?

Use this view to assess

• Tricuspid valve morphology.

• Subvalvular tricuspid apparatus.

Use this view to measure:

• No specific measurements.

Key features of view

• Right ventricle: this is an unusual 2-chamber view of the right ventricle

and atrium but can give an impression of right-sided chamber size.

• Tricuspid valve and subvalvular apparatus: as with the mitral views

the subvalvular apparatus is usually detailed. Colour flow can map

regurgitation and there can be a qualitative assessment of tricuspid

valve function. As the right ventricle is relatively difficult to see with

transoesophageal imaging this may provide a good window to look for

tricuspid valve pathology, e.g. vegetations and masses.

• Right atrium: the right atrium can be viewed.

396

CHAPTER 5 Transoesophageal examination

Deep transgastric view

Deep transgastric views are only really required when Doppler information

is needed about the aortic valve and transthoracic imaging is not possible.

The view tries to recreate a transthoracic apical 5-chamber view (Fig. 5.18).

Finding the view

• From the transgastric long axis view advance the probe further into

the stomach.

• Set the sector to 0°.

• Ensure full angulation of the probe and good contact with the stomach

wall.

What do you see?

Use this view to assess

• Global and regional left ventricle function.

• LVOT and aortic valve.

Use this view to measure

• Left ventricle function.

• Aortic and LVOT velocities (if seen - may need some sector angle

adjustment).

Key features of view

• Aortic valve and LVOT: the aortic valve lies in the far field and may be

highlighted by colour flow mapping. The primary purpose of this view

is to align the valve and outflow tract for Doppler measures.

• Left ventricle: similar to the 4-chamber view. The septum and lateral

wall are seen.

398

CHAPTER 5 Transoesophageal examination

Pulmonary artery view

A view to study the pulmonary arteries. Can be useful to assess size of

artery or look for large pulmonary emboli (Fig. 5.19).

Finding the view

• Start from the short axis aortic view. The sector may need to be

reduced slightly to 40°.

• Withdraw the probe slowly until you have a short axis view of the

ascending aorta.

• The probe may need to be angulated forward gently to demonstrate

the pulmonary artery.

What do you see?

Use this view to assess

• Ascending aorta for dissection or dilatation.

• Pulmonary artery.

Use this view to measure:

• Aortic and pulmonary artery size.

Key features of view

• Pulmonary arteries: the right pulmonary artery is seen wrapping around

the aorta and lies between the aorta and probe. The main pulmonary

artery is seen to the side of the aorta. The left pulmonary artery is not

visible.

• Ascending aorta: a short segment of the ascending aorta can usually be

seen to assess dilatation, dissection, and atheroma.

• Superior vena cava: the superior vena cava is seen in cross-section close

to the aorta and right pulmonary artery.

400

CHAPTER 5 Transoesophageal examination

Aortic views

The final views are usually the aortic views (Fig. 5.20). They can be

important for monitoring dissection or studying atheroma. They can also

be used to assess aortic flow in aortic regurgitation. The only limitation is

that TOE can not see the distal ascending aorta and proximal part of the

aortic arch as the air-filled left bronchus obscures the view.

Finding the view

• The ascending aorta is seen in the pulmonary artery view. Obtain the

short axis aortic view at 50° and then withdraw the probe slowly to

scan up the aorta as far as images are maintained.

• For descending aorta and aortic arch, start from the 4-chamber view

with a sector angle of 0° and turn the probe slowly so that it starts to

face posteriorly.

• It is usually best to turn the probe anti-clockwise until the circular

aorta is seen.

• Decrease the depth so that the aorta fills the screen and you usually

also need to reduce the gain slightly.

• The probe may then be withdrawn slowly to scan up the aorta. As the

aorta curls around the oesophagus some slight turning will be required

as the probe is withdrawn.

• The optimal view is a cross-section through the aorta. A long axis view

can also be useful and is achieved by changing the sector angle to 90°.

What do you see?

Use this view to assess

• Aortic dissection or dilatation.

• Atheroma and thrombus.

• Aortic flow, e.g. in aortic regurgitation.

Use this view to measure:

• Aortic size.

• Aortic flow.

Key features of view

• Descending aorta: there is good depiction of the aortic walls and their

layers as well as thickening and gross atherosclerosis. If measurements

are made, annotate images with the depth of the probe so that serial

measures are possible.

• Aortic arch: at the top of the descending aorta the aortic cross-section

will disappear and the vessel opens out into the arch. The origin of the

left subclavian artery may be seen. By changing the sector angle to 90°

at this point a cross-section can be maintained.

• Ascending aorta: a short segment of the ascending aorta can usually be

seen to assess dilatation, dissection, and atheroma.

402

CHAPTER 5 Transoesophageal examination

3D oesophageal views

3D oesophageal views allow the spatial orientation of anatomy and pathol-

ogy to be fully appreciated from multiple positions and in different imaging

planes (Fig. 5.21). In principle all views used for 2D imaging are also suit-

able for 3D recordings.

Finding the view

• Optimize the 2D image by adjusting the sector width, depth, and gain

settings appropriately.

• Decide on which 3D image acquisition mode you would like to use.

For larger volumes of interest then full volume acquisition provides the

largest volume of imaging. For smaller regions of interest (e.g. valves)

then live 3D or 3D zoom modes may be preferable to improve the

balance between temporal and spatial resolution, see Table 5.1.

Full volume acquisition

• This mode records over 4 cardiac cycles and then stitches these

together to form a full volume.

• After the 2D image has been optimized, select 3D/full volume.

A biplane display will appear allowing the operator to view the region

of interest to ensure that it is being adequately imaged without

foreshortening.

• Adjust the line density and sector width appropriately to optimize the

region of interest.

• Ensure that the ECG gating is adequate.

• Acquire the 3D image.

• Check for the presence of stitching artefacts and when happy accept

the acquisition.

• This mode also allows full volume colour acquisition.

Live 3D acquisition

• Optimize the 2D image and view in biplane mode to ensure optimal

probe position and adjust sector accordingly.

• Acquire live 3D.

3D zoom acquisition

• Optimize the 2D image.

• Select 3D zoom mode to show the image in a biplane view.

• A box will appear to delineate the area which will be shown in 3D

zoom. Adjust the position of the box whilst still in biplane mode to

ensure the region of interest seen in both orthogonal views is within

the guide box.

• Acquire 3D zoom.

3D OESOPHAGEAL VIEWS

403

Table 5.1 Properties of the 3D image acquisition modes

Full volume

Live

Zoom

Dimensions

90° × 90°×

60° × 30° × depth

20° × 20°–90° ×

depth of

of 2D image

90° × variable height

2D image

Real time?

Yes

Frame rate

20-40Hz

20-30 Hz

5-10Hz

(4 beats);

40-50Hz

(7 beats)

Cardiac

Left ventricle,

Any 2D image

Cardiac valves, left

structure of

mitral valve

atrial appendage

interest

Clinical

LV function.

Examine anatomy

application

colour

and guide

Doppler

interventional

procedures

Possible

Yes

presence of

stitch artefacts?

Temporal

Best

Mid

Worst

resolution

Spatial

Worst

Mid

Best

resolution

Fig. 5.21 Full volume 3D acquisition with subsequent rotation and cropping to

reveal the 3D spatial relationship between the cardiac valves. See W Video 5.17.

404

CHAPTER 5 Transoesophageal examination

3D mitral valve

The mitral valve views are usually acquired from the same views used for

2D imaging of the mitral valve and are excellent for assessing mitral valve

pathology such as mitral valve prolapse.

Finding the view

• From the mid oesophageal position obtain the optimal image of

the mitral valve using from the 4-chamber 0°, 2-chamber 75°, or

3-chamber 135° views.

• Once the image has been optimized, select the appropriate acquisition

mode.

Image acquisition modes

• The mitral valve can be easily imaged using all 3D acquisition modes:

full volume, live, and zoom.

• In full volume mode, colour Doppler can be used to acquire a 3D

colour image across the valve.

• 3D zoom allows the mitral valve anatomy to be examined in detail

with adequate spatial and temporal resolution.

What do you see?

Use mitral valve views to assess

• Mitral valve morphology (Figs. 5.22 and 5.23) and pathology.

3D applications for imaging the mitral valve

• Acquisition of 3D datasets allows post processing and the mitral valve

to be rotated to be viewed from the surgical view of the left atrium.

• 3D TOE allows a visually superior understanding of normal MV

anatomy and causes of valvular dysfunction. It allows detailed analysis

of MV anatomy to view the annulus, leaflets, and subvalvular apparatus

from different orientations and planes.

• It is becoming increasingly used to guide mitral valve repair (b p.446).

• Imaging of prosthetic mitral valves using 3D acquisition modes

can be very useful, allowing a detailed assessment of the valve and

any coexisting pathology (e.g. site of paravalvular regurgitation or

dehiscence).

Use view to measure

• 3D colour full volume data sets can be rotated and cut in different

planes and used to quantify the origin of the regurgitant jet(s) as well

as estimate the vena contracta and regurgitant orifice area.

• As 3D datasets can be viewed from multiple angles and cropped in

different planes, it allows estimation of the smallest true MV orifice by

planimetry.

• Off line reconstruction packages allow 3D MV models to be generated

from original TOE datasets (Figs. 5.22 and 5.23).

Key features of view

• Rotation and viewing through different planes allow all the valve

leaflets, annulus and subvalvular apparatus to be viewed.

406

CHAPTER 5 Transoesophageal examination

3D aortic valve

3D imaging of the aortic valve is useful for highlighting the mechanism of pa-

thology and also to guide aortic valve interventional procedures (Fig. 5.24).

Finding the view

• From the mid oesophageal the short axis 50-70° view is used.

Image acquisition modes

• 3D imaging of the aortic valve can be difficult because of its anterior

position and thin pliable cusps.

• All 3D acquisition modes can be used although multiple images

may need to be recorded when using zoom mode to ensure entire

coverage of the valve.

• In full volume mode, colour Doppler can be used to acquire a 3D

colour image across the valve.

What do you see?

Use aortic valve views to assess

• Aortic valve morphology and pathology.

3D applications for imaging the aortic valve

• It is becoming increasingly used to guide TAVI (b p.464).

• Imaging of prosthetic aortic valves using 3D acquisition modes can

be very useful, allowing a detailed assessment of the valve and any

coexisting pathology (e.g. areas of dehiscence).

Use view to measure

• 3D colour full volume data sets can be rotated and cut in different

planes and used to quantify the origin of the regurgitant jet(s) as well

as estimate the vena contracta and regurgitant orifice area.

• As 3D datasets can be viewed from multiple angles and cropped in

different planes, it allows estimation of the smallest true AV orifice by

planimetry (Fig. 5.25), aortic ring, LVOT, and proximal aorta.

Key features of view

• Anatomy of aortic valve

3D aorta

Image acquisition modes

• All 3D imaging modes can be used depending on the size of the region

of interest which is being examined.

What do you see?

Use aortic valve views to assess

• Aorta and root pathology e.g. dissection/atheroma.

3D applications for imaging the aorta

• 3D imaging of the aortic root can provide detailed assessment of

complex anatomical pathologies, e.g. aneurysm, aortic dissection.

408

CHAPTER 5 Transoesophageal examination

3D tricuspid valve

3D imaging of the tricuspid valve can be difficult because of the valve’s thin

leaflets and also its anterior position (Fig. 5.26).

Finding the view

• From the 4-chamber 0° view or transgastric RV view, rotate the probe

so that the tricuspid valve is focused on.

Image acquisition modes

• From the 4-chamber view, 3D datasets of the tricuspid valve can be

acquired.

• All 3D acquisition modes can be used although multiple images

may need to be recorded when using zoom mode to ensure entire

coverage of the valve.

• In full volume mode, colour Doppler can be used to acquire a 3D

colour image across the valve.

What do you see?

Use view to assess

• Tricuspid valve and annulus morphology and pathology.

3D applications for imaging the tricuspid valve

• Acquisition of 3D datasets allows post-processing and the tricuspid

valve to be rotated to be viewed from the surgical view of the right

atrium.

• 3D imaging allows the TV to be viewed from the atria and gives an

appreciation of its relationship to the MV and AV.

Use view to measure

• 3D colour full volume data sets can be rotated and cut in different

planes and used to quantify the origin of the regurgitant jet(s) as well

as estimate the vena contracta and regurgitant orifice area.

• As 3D datasets can be viewed from multiple angles and cropped in

different planes, it allows estimation of the smallest true TV orifice by

planimetry.

Key features of view

• Rotation and viewing through different planes allow all the valve

leaflets and to be viewed.

3D pulmonary valve

• As the pulmonary valve is the most anterior of all valves and also the

thinnest, 3D TOE is limited and it is difficult to obtain adequate 3D

views.

410

CHAPTER 5 Transoesophageal examination

3D left ventricle

3D imaging of the left ventricle can be used to help quantify LV function or

to confirm the presence of pathology (e.g. apical thrombus) (Fig. 5.27).

Finding the view

• From the 4 chamber 0° view or 2 chamber 90° view, optimize the

depth settings and ensure that the ventricle is not foreshortened.

Image acquisition modes

• Full volume acquisition mode is used to enable the best chance of

capturing the entire ventricle.

• Close inspection of the full volume datasets is necessary following

acquisition to review the image quality and to also exclude the

presence of stitch artefacts.

What do you see?

Use view to assess

• Left ventricle

3D applications for imaging the left ventricle

• Post-processing packages allow the ventricular volumes and ejection

fraction to be estimated from the 3D datasets (Fig. 5.28).

• The 3D datasets can be rotated and cropped to review images of the

left ventricle from the short axis plane.

• Assessment of regional LV function and synchrony.

Use view to measure

• Left ventricular volumes.

• Ejection fraction.

Key features of view

• Left ventricle.

412

CHAPTER 5 Transoesophageal examination

3D interatrial septum

3D imaging of the interatrial septum has become invaluable not only for

confirming dimensions of atrial septal defects but also to demonstrate the

spatial relationship of defects to surrounding structures (Fig. 5.29). These

views are also used to guide percutaneous atrial septal interventional

procedures.

Finding the view

• The optimal view is obtained from the bicaval 110° view.

Image acquisition modes

• Using full volume or zoom modes allows detailed assessment of the

interatrial septum from the bicaval view.

What do you see?

Use views to assess

• Interatrial septum.

• Right atrium.

• Left atrium.

• SVC.

• IVC.

3D applications for imaging the interatrial septum

• Acquisition of 3D datasets allows post-processing and the interatrial

septum to be rotated to be viewed from either the left or the right

atrium.

• 3D TOE allows a visually superior understanding of the atrial septal

anatomy and of pathology compared to 2D TOE.

• It is becoming increasingly used to guide percutaneous closure of atrial

septal defects.

Use view to measure

• As 3D datasets can be viewed from multiple angles and cropped in

different planes, it allows the size of defects and their relationship to

surround structures to be better appreciated.

• 3D colour full volume data sets can be used to view the flow of blood

across defects.

Key features of view

• Interatrial septum and defects.

• The relationship of the interatrial septal defects to the MV, AV,

SVC, IVC.

414

CHAPTER 5 Transoesophageal examination

X-plane

The use of X-plane imaging during TOE provides the operator with further

anatomical information and can also be useful as guidance during interven-

tional procedures. X-plane allows 2 high resolution images of the heart to

be displayed simultaneously in real time (Fig. 5.30).

Finding the view

• Obtain the appropriate 2D view.

• Optimize the 2D image settings.

• Select X-plane mode. Live imaging provides 2 orthogonal views from

the same heart beat. The initial image on the left is the baseline

reference whilst the image on the right can be electronically rotated to

any angle between 0-180°.

• When happy acquire the image.

• X-plane images can be acquired with and without the use of colour

Doppler.

Use this view to

• Examine the left atrial appendage anatomy and for pathology

(e.g. thrombus).

• When high spatial and temporal resolution is needed e.g. valve

vegetations.

418

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral valve

TOE is one of the most important tools for the assessment of mitral valve

disease and allows superb visualization of the mitral valve. The modality is

particularly good for systematic reviews of the different valve segments.

Mitral valve anatomy is described on b p.106. Briefly, there are 2 leaflets

each with 3 segments (or scallops)—a large anterior and a crescent-shaped

posterior leaflet. Assessment of stenosis and regurgitation follows the

same criteria as for transthoracic imaging (b pp.110 and 116) but TOE

allows a more detailed study of the pathology underlying regurgitation or

stenosis.

Normal findings

Views

• The mitral valve is sliced through in virtually all the mid-oesophageal

views and the ‘screenwiper’ principle allows rotation through the valve

in multiple planes (Fig. 6.1). The mid-oesophageal views also allow

alignment of Doppler and colour flow across the valve. The minimum

views are the mid-oesophageal views at around 0°, 135°, 90°, and 80°.

• The transgastric views provide additional information in both the

short axis 0° (pulled back slightly) and the long axis 90° view for the

subvalvular apparatus.

Normal findings

• 4-chamber 0° view: this classically includes A2, A1, and P1 segments of

the valve (however, there is a tendency to cut more through A2 and

P2 if the LVOT is seen and the papillary muscles are not evident).

• Long axis 135° view: equivalent to the apical 3-chamber view this gives

a good stable view of A2 and P2.

• 2-chamber 75° view: stable ‘commissural’ view to see P1 and P3 either

side of A2. Rotation of the probe allows you to swing more towards

the anterior or posterior leaflet. Slight adjustment of sector angle

will bring in the left atrial appendage and localize A1/P1 next to the

appendage.

• Transgastric short axis view or ‘fish mouth’ view has the A3/P3

segments nearest the probe. The 90° view can be used to look at the

papillary muscles and chordae.

Identifying mitral valve leaflets and segments

There are rigorous descriptions of which leaflets are seen in which view.

Initially standard views allow good orientation but as you become more

familiar you can play with these by slight adjustments of the probe to cut

through the 3D structure at any point. There are 2 tips to identify the

segments and leaflets:

• The anterior leaflet is nearest the septum/LVOT and usually appears

larger than the posterior leaflet.

• The segments are numbered so that A1 and P1 are nearest the left

atrial appendage.

420

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral regurgitation

TOE should be used to assess mitral regurgitation when:

• TTE is inconclusive or technically difficult.

• To define the underlying mechanism for planning mitral valve surgery.

TOE is particularly useful to visualize where the regurgitant jet passes

through the valve. Higher transducer frequencies and multiple views

result in more reliable measurements of both vena contracta and flow

convergence. However, the different transducer frequency, pulse repetition

frequency, and gain also mean they appear larger on transoesophageal images

than transthoracic images.

Assessment

Appearance

• Start in the 4-chamber 0° view and map the regurgitation with colour

flow. Scan through the valve at different angles to establish the shape,

direction, and pattern of the jet. Comment on:

• Where the regurgitation passes through the valve, e.g. perforation,

failure of coaptation, prolapse of a leaflet scallop.

• Direction of eccentric jets (anterior or posterior). Remember

anteriorly-directed suggests posterior valve pathology and vice

versa.

• How far back the jet extends (involving pulmonary veins?).

• If there are several jets comment on each.

• Use transgastric long axis 90° view to look at subvalvular apparatus

(Fig. 6.2). Comment on: papillary muscle and chordae with reference

to shortening and rupture.

• Report associated features, e.g. atrial size, ventricle size, and function.

3D TOE MR

• As the probe is much closer in TOE and with higher resolution, live

imaging can often be used rather than full-volume acquisition.

• Studies have demonstrated greater accuracy than 2D TOE in

identifying the position of the prolapse (see b p.428).

• Excellent resolution is possible.

• As well as being used for assessment of regurgitation, 3D TOE can

guide placement of clips for transcutaneous treatment of mitral

regurgitation.

3D colour flow Doppler

• This allows assessment of MR especially eccentric jets (Fig. 6.5).

• Acquisition does require multiple cycles and there may be problems

with artefacts on reconstruction, especially with AF.

• 2D PISA assessment is based on the assumption of a hemispherical

3D shape. However, this is not always the case and all planes can be

assessed with 3D TOE (Fig. 6.3).

• The origin of paravalvular leaks can be difficult to identify. However,

this can be made easier using 3D TOE.

422

CHAPTER 6 Transoesophageal anatomy and pathology

Grading severity

Assess severity on vena contracta, flow convergence, pulmonary venous

flow, and valve structure. Colour jet area can also be used (Table 6.1).

Colour Doppler jet area

This can be difficult to assess with TOE because sector width often does

not include the whole of the atrium. Proportional jet area is therefore

difficult to judge. 4-chamber 0° and long axis 135° views may give the best

impression.

Vena contracta

TOE provides excellent views and resolution for measurement of colour

flow through the valve.

• In mid-oesophageal views choose the plane which cuts through the jet.

• Zoom in on the colour flow through the mitral valve and record a

loop. Identify the image with maximal flow through the valve.

• The vena contracta is the narrowest region of the regurgitant jet

(usually as it passes through the valve). Report the diameter.

Pulmonary venous flow

TOE provides a unique opportunity to visualize directly all 4 pulmonary

veins and measure pulmonary vein flow (Fig. 6.4). The contralateral pul-

monary vein to an eccentric jet (i.e. left pulmonary veins for an anteriorly-

directed jet and vice versa) should be used to avoid changes in flow due

to washing of the jet into the vein.

• In 4-chamber 0° view rotate to the left to identify the left-sided veins

(b p.384). Advance or withdraw the probe to bring them into view.

The left upper pulmonary vein usually points towards the probe and

left lower pulmonary vein is perpendicular. To help with identification

place colour flow by the edge of the atrium and look for the jets of

the veins draining into the atrium. Slight changes in the plane angle can

optimize the view. Right-sided veins are identified in the same way but

with rotation to the right. Again the right upper pulmonary vein points

towards the probe and lower vein is perpendicular.

• Alternative views are: (1) 110° bicaval view rotated to the left - right

upper pulmonary vein lies parallel to the septum (2) 2-chamber 75°

(left atrial appendage) view, in which the left upper pulmonary vein lies

parallel to the left atrial appendage.

• Place the pulsed wave Doppler sample volume around 1 cm into the

chosen vein (Fig. 6.4).

• Look at the systolic and diastolic components of the spectral trace and

comment if the systolic wave is blunted or reversed relative to the

diastolic wave (normally the same direction, with systolic dominant).

Supportive measures

These can be measured as for transthoracic imaging (b p.122).

424

CHAPTER 6 Transoesophageal anatomy and pathology

Carpentier (functional) classification

The Carpentier classification (Type 1 to 3) is sometimes used to report

the functional basis for mitral regurgitation. This categorizes cause accord-

ing to leaflet motion. It is relevant to different surgical approaches.

• Normal leaflet motion (Type 1):

• Annular dilatation causes regurgitation due to failed coaptation.

• Leaflet perforation (e.g. from endocarditis).

• Excessive leaflet motion (Type 2):

• Prolapse of leaflet edge beyond the plane of the annulus.

• Mitral valve prolapse, rupture/dysfunction of the papillary muscle.

• Restricted leaflet motion (Type 3):

• Leaflet edge remains below the plane of the annulus during

systole. Usually secondary to rheumatic disease, left ventricle

dilatation, posterior wall infarction.

MITRAL REGURGITATION

425

Table 6.1 Parameters to assess mitral regurgitation

Specific signs of severity

Mild

Severe

Vena contracta

<0.3cm

>0.7cm

Jet (Nyquist 50-60cm/s)

<4cm or <20% left

>40% left atrium large &

atrium

central or wall impinging

Small & central

and swirling

PISA r (Nyquist 40cm/s)

(<0.4cm)

Large (>1cm)

None/minimal

Pulmonary vein flow

Systolic reversal

Valve structure

Flail or rupture

Supportive signs of severity

Mild

Severe

Pulmonary vein flow

Systolic dominant

Mitral inflow

A-wave dominant

E-wave dominant

(>1.2 m/s)

CW trace

Soft & parabolic

Dense & triangular

LV and LA

Normal size LV

Enlarged LV & LA

if chronic MR

if no other cause

Report as moderate if signs of regurgitation are greater than mild but there are no features of

severe regurgitation.

426

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral valve prolapse

The clear images of valve leaflets allow identification of the morphology

of mitral valve prolapse. Description of mitral valve prolapse is a common

indication for TOE because of its clinical importance to determine whether a

valve can be repaired or will need to be replaced. The commonest prolapse

is of the P2 segment of the posterior leaflet. This is amenable to a standard

repair procedure.

Assessment of prolapse

• Start by studying the regurgitation. Comment on appearance and

severity. Take particular note of the direction of the jet as a guide

to the predominant leaflet prolapse (Fig. 6.6). Anteriorly-directed

suggests posterior leaflet prolapse and vice versa. Also comment on

changes in left atrial and ventricular size and function.

• Then use the ‘screenwiper’ principle to scan through the mitral valve

at 0°, 135°, 110°, 80° (Fig. 6.7). Ensure each segment has been studied

(Fig. 6.6). Comment on which segments prolapse. If the tips of the

segment reflect back into the left atrium then report this as ‘flail’

(important when planning the operation).

• Remember that both leaflets, or more than one segment, may be

prolapsing. Report all the abnormalities.

• A transgastric 0° short axis view can be used to confirm the segment

prolapse and the long axis 90° view should be used to look at the

subvalvular apparatus to identify chordae or papillary muscle rupture.

428

CHAPTER 6 Transoesophageal anatomy and pathology

3D assessment of prolapse

The use of 3D echocardiography has lead to improvements in the

understanding of normal MV anatomy and the cause for mitral valvular

pathology.

• Set up a 3D volume from the oesophageal position. Ensure from the

biplane view that it includes all the mitral valve and in particular the

area you suspect is prolapsing.

• Once the volume position and image quality is optimized, acquire a 3D

dataset. Live 3D or 3D zoom image mode acquisition is ideally suited

to imaging of the mitral valve as the image volume usually is sufficient

for good coverage of the valve and there is adequate spatial and

temporal resolution without the limitation of stitching artefacts seen

with full volume acquisition. However, you may want to acquire a full

volume as well for later post-processing.

• Rotate, crop, and set gain settings to focus on the mitral valve.

• View the valve from the left atrium and assess valvular morphology in

detail. Identify individual scallops (remember A1 and P1 lie near the

left atrial appendage, which should be visible as a round opening in the

left atrial wall) (Figs. 6.8, 6.11).

• Confirm your impression from the 2D images of the extent of

prolapse (number of scallops, width of prolapsing scallop) and confirm

the cause of the prolapse e.g. ruptured chordae.

• In particular, use the global 3D view to resolve any uncertainties about

the number of affected scallops and position of pathology, as well as

ensuring there are no other areas of pathology on the mitral valve that

were missed on the 2D sequential views.

• 3D colour flow mapping may be useful to confirm the position of small

areas of prolapse (Fig. 6.9).

• The images can then be post-processed to create a model of the

mitral valve to aid surgery.

430

CHAPTER 6 Transoesophageal anatomy and pathology

Post-processing of 3D datasets to create mitral valve

model

• 2D echocardiography only allows the mitral valve annulus to be

measured in 2 perpendicular planes. There may be difficulties in

choosing the appropriate sites for annulus measurement due to poor

spatial resolution.

• The advent of complex post-processing software such as TomTec

and Phillips mitral valve quantification have allowed extraction of

modelling data from 3D volumes (Fig. 6.10).

• A series of 2D sections are obtained from the 3D data and the

operator defines the annulus and commissures and traces the

leaflets. The post processing software then generates a valve model.

• Different parameters of the mitral valve can then be quantified

according to a number of presets.

These advances have improved the understanding of the complex geom-

etry of the mitral annulus and has added to the surgical decision-making

process.

432

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral stenosis

TOE is not routinely used to assess mitral stenosis but stenosis should be

commented upon and graded if seen during a study. Assessment may be

needed if there are poor transthoracic windows or if the valve is being

assessed for percutaneous intervention with balloon valvotomy (b p.444).

TOE is also used intraoperatively during percutaneous interventions on

the mitral valve.

Appearance

Remember to comment on mobility, calcification, and chordae. Comment

on associated valvular lesions, left atrium, and right heart.

Grading severity

Grade severity on planimetered area (b p.434) supported by pressure

half time and pressure gradient, see Table 6.2.

Pressure half-time and pressure gradient:

• In any oesophageal view with good alignment through the valve align

the CW Doppler through the mitral valve orifice.

• For pressure half-time, measure the slope of the E-wave diastolic

flow on the spectral trace (Fig. 6.12). Trace the Doppler waveform to

obtain mean pressure gradient. Remember:

Table 6.2 Parameters to assess mitral stenosis

Mild

Moderate

Severe

MV area (cm2)

>1.5

1.0-1.5

<1.0

MV pressure half-time (ms)

<150

150-220

>220

Mean pressure gradient (mmHg)

Variable

>10

TR velocity (m/s)

<2.7

Variable

434

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral valve area = 220/pressure half-time

Planimetry

• A transgastric 0° view provides a short axis ‘fish mouth’ view of the

mitral valve. The probe may need to be withdrawn and advanced

slightly to optimize the image and ensure the leaflet tips are being

imaged. Identify the maximum opening in diastole and trace along the

inner edge of the leaflets. Report the surface area of the orifice.

3D planimetry

• 3D TOE can aid in mitral stenosis assessment as planimetry of the

mitral valve orifice can be performed on a 3D acquisition whereby

the true leaflet tip orifice can be selected within a multiplanar

reconstruction (Fig. 6.13).

• Set up a 3D volume from the oesophageal position ensuring that all of

the mitral valve is seen in the biplane view. Minor adjustments may be

needed to find the optimal view especially in the presence of drop out

shadowing which can be seen in calcific mitral stenosis (Fig. 6.14).

• When happy with the probe position, acquire the 3D image.

• Rotate, crop, and set gain settings to focus on the mitral valve and

view the valve from the left atrium.

• The dataset can be exported for post-processing. The mitral valve will be

displayed in 2 orthogonal views. The cropping plane can then be adjusted

to cut through the narrowest end-diastolic MV orifice (Fig. 6.15).

436

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral valve preoperative assessment

Transoesophageal echocardiographic assessment of the mitral valve is

essential before surgery. The key surgical decision in the patient with mitral

regurgitation is whether the valve is to be repaired or replaced. With

mitral stenosis the request for imaging is usually to assess suitability for

valvotomy or to determine severity of stenosis and effects on the left

ventricle and other valves.

What the surgeon wants to know

Mitral regurgitation

The main objectives prior to mitral valve surgery are to define:

• Underlying anatomic details of the mitral regurgitation. Include a full

assessment (b p.420) and ensure comments on:

• Severity.

• Central or eccentric.

• If prolapse, which scallops are affected and whether flail elements.

• Size of annuloplasty ring likely to be needed if repaired or size of valve

if replaced. Report:

• Mitral annulus size in 2 orthogonal planes.

• Leaflet length.

• Presence and location of annulus calcification. There is a risk of

annulus leak if in an area of repair.

• If regurgitation secondary to endocarditis, comment on complications

of the endocarditis: fistulae from left ventricle to aorta, right ventricle

or left atrium; mitral valve annulus abscess; other valve involvement in

endocarditis (typically aortic or tricuspid valve).

3D mitral valve preoperative assessment

3D TOE is eminently suited to mitral valve assessment (Fig. 6.16). Both

a 3D zoom and full volume acquisition can be used to precisely quantify

leaflet anatomy, annulus geometry, and region of prolapse, which can aid

surgical planning.

3D image acquisition of the mitral valve has the applications:

• Allows the visualization of the mitral valve from both the atrial and

ventricular aspect providing views familiar to the surgeon.

• In the assessment of certain types of mitral valve prolapse 3D TOE

accurately identifies involved segments.

• In mitral stenosis 3D TOE can provide detailed assessment of the

leaflets and their commissures as well as subvalvular apparatus.

438

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral stenosis

• Underlying anatomical details of the mitral stenosis. Include a full

assessment (b p.432) and ensure comments on:

• Severity.

• Pathological basis: rheumatic or degenerative.

• Assess suitability for valvuloplasty (b p.444).

• Size of replacement valve likely to be needed. Report:

• Mitral annulus size (in both valve axes if possible).

For all mitral surgery

• Left atrial size. A dilated left atrium (>50 mm) provides good surgical

exposure of mitral valve directly through a left atrial incision. If the left

atrium is normal size or only mildly increased the surgeon may need

an alternative surgical approach (e.g. transatrial septum).

• Assessment of cardiac function. Significant left ventricle dysfunction

caused by mitral regurgitation encourages mitral valve repair rather

than replacement.

• Reports of other valve disease, particularly the aortic valve.

Preoperative versus intraoperative assessment

The severity of mitral regurgitation may be underestimated during intra-

operative TOE. Preload, afterload, and inotropic state of the heart are

reduced during general anaesthesia. Therefore, all patients undergoing

valve surgery should have transoesophageal imaging prior to surgery.

Assessment of the valve intraoperatively should take into account the

preoperative information and changes in conditions due to the anaesthesia.

Volume loading and inotropic agents can sometimes be used to mimic

haemodynamics comparable to those without anaesthesia.

MITRAL VALVE PREOPERATIVE ASSESSMENT

439

Factors that make mitral valve repair unfavourable

• Annular calcification. It is most common in the posterior annulus and

can extend into the myocardium and leaflets.

• Marked mitral ring dilatation (>5cm in the 2-chamber view).

• Extensive leaflet disease (3 or greater prolapsed or flail segments seen).

Risk of systolic anterior motion of mitral valve post-repair

If repair is planned then it is important to assess, before surgery, the

risk of postoperative systolic anterior motion of the anterior leaflet and

consequent obstruction of the LVOT. This causes obstruction in 715% of

patients after mitral valve repair. The following findings in the preopera-

tive examination are associated with an increased risk of postoperative

systolic anterior motion of the anterior leaflet and should be reported

if present:

• Excess mitral leaflet tissue. Particularly elongated anterior leaflet

causing an increase in slack leaflet available to obstruct the outflow

tract.

• Anteriorly-displaced papillary muscles.

• Non-dilated left ventricle.

• Narrow mitral-aortic angle.

• More anterior position of the leaflet coaptation point due to

relatively large posterior mitral leaflet: Anterior to posterior leaflet

ratio <1.

• Distance from the coaptation point to the septum <2.5cm.

In high-risk cases the surgical approach may be modified. In patients with

an excessive posterior leaflet a sliding leaflet plasty can be carried out after

resection of the P2 segment. Another option is the use of a rigid ring to

increase the anterior-posterior diameter—in particular if the coaptation

line is displaced anteriorly after resection of excessive tissue.

440

CHAPTER 6 Transoesophageal anatomy and pathology

is a device which allows percutaneous edge-to-edge repair

for mitral regurgitation (Fig. 6.17). There are several anatomical features

which are assessed echocardiographically when determining the suitability

Contraindications

• Mitral valve orifice <4cm2 with secondary mitral regurgitation.

• Endocarditis.

• Cardiac mass/thrombus.

• Active rheumatic valve disease.

• Mitral stenosis.

• Previous mitral valve replacement.

• Unsuitable leaflet anatomy (calcification and/or cleft affecting leaflets in

the potential deployment zone).

• The presence of a flail leaflet when: the width of the flail segment

t15mm or the flail gap is t10mm; bileaflet flail.

Anatomic suitability

• A TOE is carried out pre device deployment to carefully analyse the

anatomy of the interatrial septum and the mitral valve leaflets, annulus,

chordae, and subvalvular apparatus (Fig. 6.18).

• The presence of an atrial septal defect/patent foramen ovale and the

thickness of the atrial septum should be noted. These will determine the

ease with which the transseptal puncture is performed.

• All standard mitral valve views should be obtained with and without

colour Doppler in order to identify the area of maximal MR as well as

the anatomy of each leaflet at that position.

is ideally at the junction of A2:P2.

Adverse factors which may hinder device deployment should be noted:

leaflet thickness; leaflet calcification; chordal fusion/calcification or

calcification of the subvalvular apparatus below the maximal area of MR.

Degenerative MR (see Fig. 6.18)

• Flail gap: should be taken in the 135* long axis, 0* 4-chamber or 90*

2-chamber view where the flail gap is largest. (Needs to be <10mm.)

• Flail width: should be taken in transgastric short axis where the flail

width is largest. (Needs to be <15mm.)

Functional MR

• Coaption depth: should be taken in 0* 4-chamber view where

coaption depth is greatest. (Needs to be <11mm.)

• Coaption length: should be taken in 0* 4-chamber view where length

is shortest. (Needs to be >2mm.)

442

CHAPTER 6 Transoesophageal anatomy and pathology

Procedure

Transseptal puncture

• The bicaval view, short axis view and 4-chamber view of the atrial

septum should all be obtained to demonstrate the anatomy. The

trans-septal catheter tip can be watched moving into the fossa ovalis

causing tenting (Fig. 6.19).

• Generally the puncture should be 3-4cm from the mitral valve

although this should be modified according to the site and mechanism

of the pathology.

• Following successful puncture, views are obtained to help the safe

navigation of the catheter and then guidewire into the left upper

pulmonary vein (avoiding the left atrial appendage).

Introduction of guide catheter and MitraClip®

• Using a modified short axis view the guide catheter/dilator are

introduced. The guide catheter has echogenic markers on it helping to

identify when it has crossed the interatrial septum.

inserted

until visible in the mid LA.

is navigated to a position where it straddles the MV.

above the MV.

Crossing the mitral valve

• Using a combination of the LVOT and bicommissural views the

clip is positioned directly over the target area of the MV. Biplane

echocardiography can be useful to confirm this position in 2

orthogonal views.

• Correct position is confirmed using colour Doppler and the clip

should ideally bisect the regurgitant jet equally.

• The clip is advanced into the LV and the superior aspect of the gripper

arms should be clearly identified below the MV leaflets.

• Live 3D TOE images can also help confirm the positioning and that the

clip is perpendicular to the closure line of the valves (Fig. 6.20).

MitraClip® insertion and grasping

• Once the positioning of the clip has been confirmed it is retracted

towards the MV leaflets. Echocardiography is pivotal to ensure that

there is no distortion to the valvar/subvalvar apparatus and that

perpendicularity is maintained.

• The moment of grasp should be recorded to ensure that a suitable

amount of leaflet is held within each arm of the clip.

Confirmation of leaflet grasping and device deployment

• Adequate grasp is confirmed by visualizing the anterior and posterior

mitral valve leaflets from the LVOT and 4-chamber views.

• It is important to note the leaflet insertion point and leaflet movement

is adequate.

• When happy with adequate leaflet grasping the clip arms are closed to

approximately 60° and final images are performed to demonstrate the

accurate placement of the clip, the reduction in the degree of MR and

the absence of mitral stenosis.

MITRACLIP^®

443

• The MitraClip^® is then fully deployed and the valve reassessed to

determine the haemodynamic success of the procedure, any potential

requirement for a second clip, and the size of the residual defect from

the transeptal puncture.

Fig. 6.19 Positioning of catheter for transseptal puncture. Tenting (T) of the

inter-atrial septum at the fossa ovalis caused by the transseptal catheter is clearly

seen, with the two views allowing superoinferior adjustment (a, bicaval) and

antero-posterior adjustment (b, modified short axis aortic). LA = left atrium,

RA = right atrium, T = tenting.

Fig. 6.20 3D TOE of the mitral valve visualized from the left atrial aspect during

above the valve leaflets to ensure perpendicularity

with the closure line of the valve.

444

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral valve balloon valvotomy

TOE is performed routinely to assess suitability for percutaneous valvotomy

for treatment of mitral stenosis. Contraindications to intervention that should

be reported include:

• Left atrial appendage thrombus.

• Moderate mitral regurgitation or greater.

• Severe aortic or tricuspid valvular disease.

Echocardiographic scoring of mitral valve morphology can be preformed

to predict successful outcome. The commonest is the Wilkin’s scoring

based on 4 features each scored 1-4, giving a minimum score of 4 and

maximum of 16. The lower the score the more suitable the valve for

balloon valvotomy. A score of >8 suggests poor long-term outcome with

percutaneous intervention.

Leaflet mobility

1 Highly mobile with restriction of leaflet tips only.

2 Mid portion and base of leaflets have reduced mobility.

3 Valve leaflets move forward in diastole mainly at the base.

4 No or minimal forward movement of the leaflets in diastole.

Valvar thickening

1 Leaflets near normal (4-5mm).

2 Mid leaflet thickening, pronounced thickening of the margins.

3 Thickening extends through entire leaflet (5-8mm).

4 Pronounced thickening of all leaflet tissue (8-10mm).

Subvalvar thickening

1 Minimal thickening of chordal structure just below the valve.

2 Tickening of chordae extending up to 1/3 of chordal length.

3 Thickening extending to the distal 1/3 of chordae.

4 Extensive thickening and shortening of all chorda extending down to

the papillary muscles.

Valve calcification

1 A single area of increased echo brightness.

2 Scattered areas of brightness confined to the leaflet margins.

3 Brightness extending into the mid portion of the leaflets.

4 Extensive brightness through most of the leaflet tissue.

446

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral valve repair

Postoperative assessment

Assessment of mitral valve repair should be based on:

Residual regurgitation

Despite competent valve at surgical inspection and leak test by the sur-

geon there may still be significant valvular regurgitation in the beating,

volume-loaded heart. This may be due to ischaemic wall dysfunction or

systolic anterior motion of the mitral leaflet. Use standard 2D and colour

images to assess severity, location, and likely underlying mechanism.

3D image can provide much more precise location and mechanisms of

residual regurgitation.

• Moderate to severe residual regurgitation usually requires surgical

revision or conversion to valve replacement.

• Para-annulus leak can occur after repair if there was a large posterior

leaflet resection. Even mild degrees of para-annulus leak usually

require further surgical revision to avoid postoperative haemolysis.

New stenosis

After repair of the mitral valve the repaired leaflet usually appears thickened,

shortened, and almost immobile. Use CW Doppler to assess trans-mitral pres-

sure gradient and pressure half-time. However, pressure half-time method

may be inaccurate immediately postoperative (the method assumes that

the left atrial and ventricular compliance do not affect the pressure decline,

but up to 72 hours after surgery compliance is altered). Interpret orifice

area taking into account heart rate and stroke volume. Stenosis is often

due to under-sized annuloplasty.

Systolic anterior leaflet motion/left ventricle outflow obstruction

Systolic anterior leaflet motion/left ventricle outflow obstruction can be

due to mitral valve repair with or without concomitant basal septal hyper-

trophy, but also can be caused by haemodynamic factors. Inotropic agents,

vasodilators, and low volume states provoke systolic anterior leaflet motion/

left ventricle outflow obstruction in susceptible patients and have to be

discontinued before considering re-intervention. In some patients beta-

blockers may be useful. To demonstrate systolic anterior motion of the

mitral leaflet use the aortic long axis 135° view. 2D and M-mode images

can demonstrate abnormal leaflet movement. However, Doppler measure-

ments have to be performed in gastric views, which may be difficult in

theatre and the peak gradient of outflow tract should be differentiated

from the mitral regurgitation jet.

Consider whether effects can be reduced by changes in cardiac physiology

(improved left ventricle cavity size and diastolic filling): increase left ventri-

cle filling, stop/reduce positive inotropic drugs, commence beta-blockade,

pace the ventricle. Monitor effectiveness of medical treatments with repeat

echocardiography. If medical management fails surgical revision of repair or

valve replacement may be indicated.

MITRAL VALVE REPAIR

447

Left ventricular function

Hypo- or akinesis of the lateral and inferoposterior wall can be due

to circumflex artery injury if sutures are too deep into the mitral ring.

New impaired posterior wall contraction is most likely due to air embo-

lism into the right coronary which is usually reversible with or without

additional cardiopulmonary bypass support.

Aortic valve

Aortic valve competence can be impaired by deep suture placement in

the mitral anterior annulus or significant reduction of mitral annulus in

patients who has minimal aortic cusp coaptation reserve before the mitral

valve repair.

De-airing

During cardiopulmonary bypass air can be trapped in pulmonary veins,

the left ventricle apex, or left atrial appendage. This air is mobilized by the

surgeon before coming off bypass and enters the left ventricle and aorta.

As it is expelled it resembles the typical pattern of agitated saline (as might

happen if there was a massive right-to-left shunt during contrast echocar-

diography). Remaining air can be scanned for after de-airing.

448

CHAPTER 6 Transoesophageal anatomy and pathology

Mitral valve replacement

Post-operative assessment

Mechanical valve dysfunction is more likely with: over-sized prosthesis;

small left ventricle cavity; excessive subvalvular apparatus, double valve

replacement; anatomical mechanical prosthesis orientation. Bioprostheses

dysfunction may be due to: distorted annulus due to over sizing or suture

looping of cusps. The key features to assess immediately after replacement

are:

Valve prosthesis regurgitation

Use colour flow to look for normal prosthesis wash jets (closing jets) and

differentiate from paravalvular regurgitation. If present consider:

• Severity: for biological valves mild central jet is normal. Small

degrees of paraprosthetic regurgitation (mechanical and biological

valves) immediately after surgery often improve with protamine

administration. If moderate to severe central regurgitation and

restricted prosthetic cusp opening/closing, surgical intervention is

normally indicated. 3D image is highly recommended for identifying

the location and mechanism of regurgitation.

Valve prosthesis opening

Use 2D and 3D imaging to look for symmetrical, synchronized opening

and closing of prosthesis leaflets (Figs. 6.21 and 6.22). Look for functional

stenosis (measure prosthesis mean gradient and effective orifice area).

If abnormal opening consider:

• Relation between prosthetic valve and subvalvular apparatus: with

mechanical bileaflet prostheses, opening and closing may be reduced

or restricted because the leaflets impinge on the subvalvular apparatus

(posterior leaflet may be preserved in valve replacement).

• Left ventricle filling and contraction: If not adequately filled or poorly

contracting, re-evaulate when filling status and contraction are brought

to normal level. If prosthesis still dysfunctional surgical intervention is

advisable.

LVOT obstruction

Assess valve movement with 2D and 3D imaging and colour flow map-

ping in the outflow tract. PW Doppler in the outflow tract can be used

in transgastric views. Obstruction may be due to septal hypertrophy

combined with a high profile prosthesis intruding into the outflow tract.

450

CHAPTER 6 Transoesophageal anatomy and pathology

Cardiac function

After mitral surgery use 2D imaging to re-assess global and regional left

and right ventricular function. With acute correction of regurgitation, left

ventricular ejection fraction can be expected to drop (e.g. from 60-70% to

40%) due to sudden reduction in left ventricular stroke volume, without pro-

portional reduction in left ventricular cavity size, combined with a variable

degree of underlying impaired contractile function. Mitral valve replace-

ment for mitral regurgitation has more adverse physiological effects on left

ventricular function than repair.

• If left ventricular filling is adequate but cavity is dilated and global

ejection fraction is <30% consider inotropic support and monitor

response with echocardiography until stable haemodynamics.

• If there is a new lateral or inferoposterior wall motion abnormality,

consider whether the circumflex artery could have been damaged.

Large posterior wall hypokinesis can be caused by air embolism,

additional support may be required.

• Always consider other general causes for acute severe deterioration in

global cardiac dysfunction after cardiopulmonary bypass.

452

CHAPTER 6 Transoesophageal anatomy and pathology

Aortic valve

Very good views of the aortic valve can be obtained with TOE because

there is only the left atrium, which is a clear fluid-filled window, between

the valve and the probe. Aortic valve anatomy is described on b p.132

but essentially comprises of 3 cusps and associated sinuses of Valsalva,

named after the coronary arteries that derive from them (right, left, non-

coronary).

TOE is indicated to study the aortic valve when transthoracic images are

of insufficient quality or better spatial resolution is needed to provide

complete assessment of valve pathology, for example vegetations, aortic

root abscesses, aortic valve area and prosthetic valve function.

Normal findings

Views

• The best views to see the aortic valve are the 50° short axis view

and 135° long axis view (Fig. 6.23). These can be supported by the

5-chamber 0° left ventricular outflow view.

• Additional information is obtained from transgastric views which

provide better alignment for Doppler. The aortic valve can be studied

with a transgastric long axis 110° view and the deep transgastric 0°

view.

Aortic valve

• 5-chamber 0° left ventricular outflow view: this provides a limited first

view of the left ventricular outflow and with colour flow can be used

to judge whether there is any aortic regurgitation.

• Short axis 50° view: this is the first clear view and is similar to the

transthoracic parasternal short axis but upside down. A classic

Y-shaped cross-sectional view of the cusps is seen (left on the right,

right on the left and non nearest the probe). To optimize the image

try slight rotation or movement of the probe up and down. Get all

3 cusps in view, of equal size. Withdraw the probe further to bring

the coronary arteries, sinotubular junction, and then ascending aorta

into view. Advance the probe to see the LVOT. Colour flow mapping

allows positioning of aortic regurgitant jets. This view also allows the

stenotic valve area to be measured.

• Long axis 135° view: this view is similar to the transthoracic parasternal

long axis. Right and non-coronary cusps are seen (non-coronary

nearest the probe and right nearest the right ventricle). Use the view

to measure aortic root, sinotubular junction, and valve annulus.

• Transgastric 110° long axis view: this view allows the outflow tract to

be aligned with Doppler. The aortic cusps are sometimes seen in the

far field but it can be difficult to get a clear image. Colour flow can

help to pick out the outflow tract.

• Deep transgastric view: this is an alternative to align the Doppler with

the outflow tract and valve. It provides an equivalent view to the

transthoracic apical 5-chamber but is difficult to obtain. If there are

good transthoracic windows it will not add more information.

454

CHAPTER 6 Transoesophageal anatomy and pathology

Aortic stenosis

Evaluation of aortic stenosis with TOE follows the same routine as for

transthoracic but with more emphasis on 2D imaging to assess valve

pathology. The criteria to determine severity (Table 6.3) are the same as

transthoracic echocardiography (Table 3.3).

Assessment

Bear in mind the potential causes of aortic stenosis:

• In all the views look for evidence of calcification.

• In the 50° short axis view look at number of cusps.

• Look at associated structures—aortic root dilatation etc.

Grading severity

2D-imaging

In 50° short axis view and 135° long axis view look at valve motion. If the

valve appears to open normally aortic stenosis is unlikely to be present.

In the 135° long axis view, if the cusps separate by >12mm aortic stenosis

is mild or better.

Planimetered valve orifice

• In 135° long axis view obtain a clear image of all cusp edges.

• Move the probe back and forth until the cusp tips in systole are seen

in plane.

• Zoom onto the valve and store a loop. Scroll through the loop and try

and identify the largest opening during systole.

• Trace along the inner edge of the cusps.

• Report the surface area of the orifice.

Problems with planimetered measures:

Shadowing from heavy calcification can make it difficult to get an accurate

area or it may be difficult to the get the open tips in systole in plane with

the probe.

Doppler assessment

Both the velocity across the valve and continuity equation require aortic

valve vti (or peak flow), LVOT vti (or peak flow), and LVOT dimension.

It is often easier and more accurate to do this with TTE but can also be

done during a transoesophageal examination.

• Use a transgastric 110° long axis or deep transgastric view to line up

the CW Doppler with the aortic valve and aorta (Fig. 6.24).

• Acquire a spectral recording and trace the aortic vti.

• In the same view acquire a PW Doppler in the LVOT and trace the vti.

• Measure the LVOT diameter in the 135° long axis view.

• Report the peak velocity or use the standard continuity equation:

valve area = LVOT area × LVOT vti/aortic vti

456

CHAPTER 6 Transoesophageal anatomy and pathology

Aortic regurgitation

In evaluation of aortic regurgitation with TOE there is more emphasis

on 2D imaging to assess cause. Doppler criteria to determine severity

(Table 6.4) are as for transthoracic (Table 3.4).

Assessment

Bear in mind potential causes of regurgitation and study both valve and

aortic root (b p.310).

• In all the views look for evidence of abnormal valve motion.

• In the 50° short axis view look at the valve and position of

regurgitation. Study the sinuses and aortic root.

• In the 135° long axis view look at the aortic root dimension and check

for dissection.

• Comment on the location and direction of jet. 3D imaging can be of

use for identification of the origin of regurgitation jets around the

aortic valve. For this 3D colour flow mapping is required.

Grading severity

Colour flow Doppler

• Aortic regurgitation can first be identified in the 5-chamber 0° view

although this may not give you an idea of severity.

• The 50° short axis view with colour flow provides an impression of

where the regurgitation is and the area of the jet relative to the LVOT.

• The 135° long axis view with colour flow provides the most

information to assess severity. This view can be used to assess vena

contracta and jet width relative to LVOT (Fig. 6.25).

3D colour flow mapping

• To collect a 3D colour flow dataset (Fig. 6.26) use the oesophageal

window with the 3D volume optimized to include the aortic valve.

• It is often easiest to start with your optimized 2D long axis 135° view

or 50° short axis view of the aortic valve before switching to the

biplane view to set up the 3D volume.

• Remember that the colour flow mapping full volume acquisitions tend

to be over more heartbeats and therefore are more prone to stitching

artefacts.

• Large jets are often more complex and therefore more difficult to

characterize on 3D. The easiest jets to localize are thin, long jets or

multiple small jets. 3D can be very useful to identify the presence of

multiple jets in a single global view that may have been missed, or

thought to be the same jet, on sequential 2D views.

458

CHAPTER 6 Transoesophageal anatomy and pathology

Aortic flow reversal

• In the 90° long axis aortic view PW Doppler with some correction for

angle will allow assessment of aortic flow in diastole. Some diastolic

flow reversal is normal. Holodiastolic flow reversal is associated with

severe aortic regurgitation (Fig. 6.27).

Continuous wave Doppler

• For CW assessment of aortic regurgitation a transgastric 110° long axis

view or deep transgastric view is required to align the Doppler signal.

• Look at density of signal, deceleration slope and peak velocity.

However, these are less accurate with TOE because of technical

limitations in alignment.

Table 6.4 Parameters to assess severity of aortic regurgitation

Specific signs of severity

Mild

Severe

Vena contracta

<0.3cm

>0.6cm

Jet (Nyquist 50-60cm/s)

central, <25%

central, >65% of LVOT

of LVOT

Descending aorta

No or brief early

Holodiastolic flow reversal

diastolic flow reversal

Supportive signs of severity

Mild

Severe

Pressure half-time

>500ms

<200ms

Left ventricle

Normal LV

Moderate or greater (only

for chronic lesions) LV

enlargement (no other cause)

Report as moderate if signs of regurgitation are greater than mild but there are no features of

severe regurgitation.

460

CHAPTER 6 Transoesophageal anatomy and pathology

Aortic valve preoperative assessment

Thorough preoperative assessment allows careful planning of surgery

on the aortic valve. Aortic valve replacement is the most frequently per-

formed valve surgery with an increasingly elderly population. Preoperative

information should include data on the valve, the left ventricle, and the

aorta.

What the surgeon wants to know

General

Before all types of aortic surgery the basic information needed is:

• Aortic valve cusp morphology and function.

• Aortic root size (look for abscesses if endocarditis present).

• Aortic annulus size (to judge prostheses size if replacement planned).

• Evidence of sinotubular junction dilatation (if >25% bigger than aortic

annulus then aortic homograft or stentless bioprosthesis may be

contraindicated).

• Ascending aortic dimension and geometry (ascending aorta dilatation

>45mm may require replacement).

• Descending aorta size and flow velocity.

• Anatomy and dynamics of LVOT (in surgery for stenosis check for a

subaortic stenosis to account for gradient).

• Coronary ostia size, location, and flow velocity (check for ostial

stenoses and coronary sinus calcification that might complicate

coronary reimplantation in aortic root replacement).

• Left ventricle cavity size, function, and degree of hypertrophy.

Bicuspid valves

In young patient with bicuspid aortic valve pay particular attention to:

• Concomitant abnormalities in LVOT.

• Coronary anatomy.

• Aortic root, arch, and descending aortic structure.

Aortic remodelling

In aortic root remodelling check native valve can be preserved. Look at:

• Aortic cusp morphology and mobility.

• Aortic sinus geometry.

3D aortic valve preoperative assessment

• Assessment for suitability and guiding transcatheter aortic valve

implantation, see b p.464.

462

CHAPTER 6 Transoesophageal anatomy and pathology

Aortic valve replacement

Postoperative assessment

Assessment of an aortic valve replacement should be based on:

Valve prosthesis opening

With 2D, 3D imaging (and if appropriate M-mode) look at valve opening

and closing (Fig. 6.28). Assess velocity across the aortic valve with CW

Doppler from a transgastric view. Expect a mean gradient of <15mmHg.

Valve prosthesis regurgitation

Check for regurgitation with colour flow. There may be small closing jets

or some mild paraprosthetic regurgitation particularly before protamine

is given. If regurgitation is seen, determine severity and location (trans- or

paraprosthetic). If bioprosthetic valve implanted, consider whether due to

annulus distortion. Paravalvular regurgitation is more likely with a severely

calcified aortic annulus, infected aortic valve or redo aortic valve surgery.

Endocarditis

If surgery was for endocarditis ensure any abscesses or fistulae that were

present have been excluded or closed.

Cardiac function

For all surgery, determine global and regional cardiac function using standard

techniques (b p.480). Expect an ejection fraction of 40-60% if normal

before surgery. If significant impairment consider causes as for mitral valve

surgery (b p.447) and in particular consider whether there has been

damage to coronary artery ostia.

Coronary arteries

Check for proximal coronary obstruction or occlusion. In short axis views

assess proximal coronary lumen size and flow velocity. Acute coronary

obstruction can be due to acute thrombus, emboli, prosthesis mal-position

and/or oversizing, or abnormal coronary anatomy in congenital aortic

valve disease. Depending on the degree and location of coronary ostia

obstruction, it can cause failure to wean off cardiopulmonary bypass at the

outset or delayed onset of cardiac arrest by the time of chest closure.

De-airing

During cardiopulmonary bypass air can be trapped in pulmonary veins,

the left ventricle apex, or left atrial appendage. This air is mobilized by the

surgeon before coming off bypass and enters the left ventricle and aorta.

As it is expelled it resembles the typical pattern of agitated saline (as might

happen if there was a massive right-to-left shunt during contrast echocar-

diography). Remaining air can be scanned for after de-airing.

Other

Monitor for LVOT obstruction and systolic anterior motion of mitral valve

(see b p.446). If there has been septal myoectomy check for a ventricular

septal defect.

464

CHAPTER 6 Transoesophageal anatomy and pathology

TAVI

Assessment of patient suitability for transcatheter aortic valve implantation

(TAVI) requires detailed imaging including echocardiography. A full study

is performed either with TTE or TOE but often both.

Assessment before TAVI

The study needs to include information on:

Aortic valve

The information needed by the operator relates to the severity of aortic

stenosis to confirm that TAVI is required, the anatomy to determine whether

the valve is suitable for percutaneous closure, and the presence of other

pathology that may influence patient outcome. The report should include:

• Whether the valve is tricuspid valve or bicuspid (bicuspid valve

currently a contraindication).

• The true severity of aortic stenosis: aortic valve area <1cm2 or

<0.6cm2/m2. Accurate planimetry of the valve based on careful 2D or

3D alignment with leaflet tips should be included.

• Extent and location of valve calcification: possibility of coronary

obstruction by displaced calcification.

• Size and shape of aortic sinuses and sinotubular junction.

• Aortic annulus size: measure annulus size in a parasternal long axis

view or from a 3D dataset from hinge point to hinge point of valve

leaflets—crucial for correct device sizing (Fig. 6.29).

• Report on the presence of left ventricular septal hypertrophy:

prominent septal bulge may complicate device positioning.

• Try and determine location of coronary ostia and height from annulus

(coronary height). Table 6.5: assess risk of coronary obstruction by

device.

General

Assess ventricle and other valves:

• Assess left ventricular hypertrophy and function and cavity size:

particularly important for transapical approach.

• Assess right ventricular function and estimate pulmonary pressure: risk

of RV deterioration during procedure.

• Mitral valve anatomy and function: significant mitral regurgitation is a

relative contraindication.

• Aortic calcification: extensive descending aorta atheroma may increase

embolic risk.

• Presence of pleural and pericardial effusions: to allow early

identification of any complications.

In patients with significant left ventricular dysfunction and aortic stenosis

a dobutamine stress echo may be helpful in clarifying both the severity of

the aortic stenosis and the degree of left ventricular hibernation.

TAVI

465

Importance of annulus size

)

are suitable for annulus sizes ranging from 18-27mm (Table 6.5). If there

is concern over measurement accuracy then comparison with data from

angiography, computed tomography, and magnetic resonance aortography

may be required to decide on eventual device size.

The degree of valvular calcification and LVOT size are also important

factors in correct device sizing. Undersizing the prosthesis may lead to

paravalvular regurgitation, oversizing may lead to poor stent expansion,

coronary obstruction or root rupture.

Table 6.5 TAVI devices

Device

Annulus

Sinus of Sinotubular Coronary

range

Valsalva junction

height

26mm

20-23mm

t27mm d40mm

t14mm

29mm

24-27mm

t28mm d43mm

t14mm

23mm 18-21.5mm

N/A

t10mm

21.5-24.5mm N/A

N/A

t11mm

Fig. 6.29 Measurement of aortic annulus size by 2D (left) and 3D (right) TOE.

466

CHAPTER 6 Transoesophageal anatomy and pathology

Assessment during TAVI

Peri-procedural echocardiography, usually with TOE (although both ICE

and TTE have been used), is key to ensuring accurate valve deployment

and excluding any complications (Fig. 6.30).

TAVI procedure steps

Crossing the aortic valve

• Assess position of wire across valve—usually in commissure between

non- and right-coronary cusps.

• Exclude pericardial effusion due to wire perforation of left ventricle.

• Assess degree of aortic regurgitation once wire and catheter across

valve.

Balloon aortic valvuloplasty

• Confirm balloon position across aortic valve.

• Assess degree of expansion of balloon.

• Quantify aortic regurgitation post valvuloplasty.

• Assess change in aortic valve motion—sufficient to allow passage of

prosthesis?

Prosthesis positioning and deployment

• The exact position of the prosthesis depends on the type used but

both require precise placement to within 1mm to ensure correct

function.

• Full expansion of the balloon during deployment should be noted.

• Degree and extent of any paravalvular regurgitation post

deployment—rarely a second balloon inflation may be needed.

Assessment of any complications

The echocardiographer must be alert to potential complications and con-

tinuously monitor for:

• Decline in left or right ventricular function following rapid pacing or

prosthesis deployment.

• Pericardial effusion and tamponade due to ventricular or annulus

perforation.

• Prosthetic dysfunction due to stuck leaflets.

• Paravalvular regurgitation.

• Aortic injury or dissection.

• Coronary obstruction.

• Thrombus formation on wires and sheaths.

468

CHAPTER 6 Transoesophageal anatomy and pathology

Tricuspid valve

The tricuspid valve is often included in a transoesophageal study but,

unless the indication is a study of endocarditis, is not the primary focus.

Generally the right heart is more difficult to study with TOE because it lies

furthest from the probe.

Normal findings

Views

• The best views are: 4-chamber 0°; bicaval 110°; short axis 80° (right

ventricular inflow/outflow); and right ventricle transgastric 90°.

Findings

• 4-chamber 0° view: the tricuspid valve lies on the left and the probe

may need to be advanced slightly to optimize the image.

• Bicaval 110° view: usually used to study the atrial septum, if the probe

is advanced slightly, the tricuspid valve often comes into view in the far

field. This view usually gives good alignment for Doppler studies.

• Right ventricle 80° short axis view: the aortic valve appears in cross-

section in the centre of the view with the right ventricle wrapped

around in the far field. This view gives a good image of both tricuspid

and pulmonary valves with tricuspid valve on the left.

• Transgastric 90° long axis view: from a standard long axis view of

the left ventricle, clockwise rotation of the probe to the right can

sometimes bring the right ventricle with the tricuspid valve and

subvalvular apparatus clearly into view.

Tricuspid regurgitation and stenosis

Assessment of regurgitation

Assess regurgitation on appearance and severity according to the standard

transthoracic guidelines (b p.158). Vena contracta (Fig. 6.31), PISA, CW

tracing, valve structure, and right heart size are usually possible with TOE,

whereas jet area and hepatic vein flow are not. See Table 6.6.

Assessment of stenosis

Assess stenosis on appearance (leaflet thickening or restriction) and severity

according to the transvalvular gradient. Remember: severe tricuspid stenosis

is usually associated with a gradient of 3-10mmHg.

470

CHAPTER 6 Transoesophageal anatomy and pathology

Pulmonary valve

Both transthoracic and transoesophageal imaging tend to have limited

views of the pulmonary valve. There are no consistent views in TOE that

allow Doppler alignment through the valve apart from modified trans-

gastric views in some patients.

Normal findings

Views and findings

• The most useful views are based on the short axis 50-80° (right

ventricular inflow/outflow) view. This is a short axis view through

the aortic valve in which the pulmonary valve is seen lying behind and

slightly to the right of the aortic valve. The image may be optimized by

changing the angle slightly from between 50° and 90° until the leaflets

of the pulmonary valve are seen opening and closing. Short axis views

of the pulmonary valve are now possible using X-plane in this view and

aligning the second plane through the valve.

Pulmonary regurgitation and stenosis

Assessment of regurgitation

Colour flow mapping of the pulmonary valve identifies small regurgitant

jets in most people—usually to one edge near the aortic valve. If there

appears to be more regurgitation than normal, comment on size, site, and

severity. Grade severity as mild, moderate, or severe based on colour flow

mapping criteria (b p.172). It may also be possible to use PW Doppler

in the pulmonary artery to look for holodiastolic flow reversal consistent

with severe pulmonary regurgitation. Remember to comment on the right

heart. See Table 6.7.

Assessment of stenosis

Pulmonary stenosis is usually valvular and congenital (e.g. related to rubella,

Noonan’s, or tetralogy of Fallot). Comment on valve appearance and

appearance of related structures (i.e. pulmonary artery, right heart). It is

difficult to align Doppler measures across the pulmonary valve with TOE

but the degree of opening using 2D/3D may be used as an estimate of

severity. See Table 6.8.

472

CHAPTER 6 Transoesophageal anatomy and pathology

Endocarditis

TOE has better sensitivity and specificity than TTE for identifying

vegetations. The higher spatial and temporal resolution can identify

smaller vegetations with rapid movement. Image quality is also better to

identify complications of endocarditis: aortic root, fistulae, and valve dys-

function such as leaflet perforation. Remember a normal echocardiogram,

including TOE, never excludes endocarditis.

Assessment

Use a full systematic examination with focus on both left and right-sided

valves. Report on:

Vegetations

• Vegetations tend to appear as masses on valves (rarely, septum and

chamber walls (Fig. 6.32). Focus on each valve (aortic, mitral, tricuspid,

and pulmonary valve) and vary position slightly while watching for

‘flicking’ bright objects attached to valve. Record loops and scroll

through frame-by-frame to pick out any abnormal mobile elements.

• If one is seen, move probe position and see if you can see it in multiple

planes. Consider possible differential diagnoses, e.g. fibrin strand

(Lambl’s excrescence), chordae (perhaps ruptured).

• If vegetation, also look for ‘seeded’ vegetations where the vegetation

(or its associated regurgitant jet) touches other valves or walls

(e.g. outflow tract, septum and aorta).

• Report: location, number, size, functional effect.

Abscess

Look particularly at valve rings (but also study leaflets) focus on aortic

root and mitral valve. The aortic root can be seen particularly well so

look for thickening, ‘boggy’ appearances or frank abscesses. If after valve

surgery, remember there may be some normal inflammation associated

with the operation. Report position, size, functional effects (compression)

and whether the abscess has now opened into a cavity (if so, say which).

Fistulae

These can usually be best seen with TOE. Suspect a fistula if there is

a known abscess, a new murmur has been heard or there has been a

sudden haemodynamic change in the patient. Use colour flow mapping

to look for abnormal flow and cavity jets. Fistulae can be between any

adjacent cavities where there has been infection e.g. around valves, aorta

to right heart.

Valve dysfunction

If there is a vegetation give details of functional effect on valve. Even if

you have not seen a vegetation look for suspicious valve dysfunction in a

systematic manner and report.

Pericardial effusion see b p.298.

475

Chapter 7

Transoesophageal

anatomy and pathology:

chambers and vessels

Left ventricle

476

Left ventricular size and mass

478

Left ventricular function

480

Left ventricular ranges

482

Right ventricle

484

Right ventricular size

486

Right ventricular function

488

Right ventricular ranges

489

Left atrium 490

Left atrial size

490

Left atrial appendage

492

Pulmonary veins 494

Right atrium 496

Right atrial size

496

Right atrial features

498

Coronary sinus 498

Atrial septum 500

Atrial septal defects and patent foramen ovale 502

Contrast study for intracardiac shunts

506

Ventricular septum 508

Pericardium 510

Pericardial effusion

512

Cardiac tamponade 512

Aorta 514

Aortic size

516

Aortic atherosclerosis

518

Aortic dissection

520

Intramural haematoma 524

Aortic transection or traumatic aortic disruption

524

Aortic coarctation 526

Sinus of Valsalva aneurysm 526

Thoracic aortic aneurysm 526

Masses 528

Cardiopulmonary bypass and coronary artery surgery 530

Haemodynamic instability 534

Mechanical cardiac support 538

Pleural space and lungs 542

Pacing wires and other implants 544

476

CHAPTER 7 Transoesophageal chambers and vessels

Left ventricle

TTE usually provides sufficient information to assess the left ventricle and

should be the echocardiographic modality of choice. With TOE the left

ventricle is in the far field and it can be difficult to obtain unforeshortened

views. Transgastric imaging allows accurate measures from stable short

axis views. Nevertheless, during a transoesophageal study assessment

should be made of the left ventricle, even if limited, to gain an impres-

sion of left ventricular size and function and help interpretation of other

findings.

Anatomy is described on b p.192. Briefly, the left ventricle is a muscular

cavity with a septum dividing it from the right ventricle. The ventricle has

anterior, inferior, lateral and inferolateral (or posterior) walls.

Indications for transoesophageal imaging

TOE is indicated when transthoracic windows are poor, in particular situations

such as in Intensive Care Unit or Cardiac Recovery, or when intraopera-

tive evaluation of cardiac function is needed during cardiac surgery.

Normal findings

Views

The key views to assess the left ventricle are the 4-chamber 0°, long axis

135°, 2-chamber 80°, and transgastric 0° short axis view (Fig. 7.1).

Findings

• 4-chamber 0° view: equivalent to the apical 4-chamber but usually with

marked foreshortening of the left ventricle. The septum is on the left

and lateral wall on the right. To realign the plane through the apex try

probe retroflexion until the apex comes into view. The probe may

lose contact with oesophagus on retroflexion.

• Long axis 135° view: equivalent to the parasternal long axis it is often

easier to align through the apex with gentle rotation. The septum

(anterior portion) is seen by the left ventricular outflow and the

posterior (inferolateral) wall is on the left.

• 2-chamber 70-90° view: equivalent to an apical 2-chamber view. The

inferior wall is on the left and anterior wall on the right. This is a

preferred view for measuring left ventricle size.

• Transgastric short axis 0° view: the best view to confidently assess left

ventricle function and obtain systolic and diastolic measures of cavity

size and wall thickness. Equivalent to a parasternal short axis view.

Advancing and withdrawing the probe may make it possible to scan

through the left ventricle in cross section from apex to mitral valve.

The walls of the ventricle are the opposite order to the parasternal

short axis, i.e. inferior wall lies nearest the probe and anterior in the

far field with septum on the left and lateral wall on the right.

478

CHAPTER 7 Transoesophageal chambers and vessels

Left ventricular size and mass

Report quantitative measures of size (Tables 7.1 and 7.2) if measurements

are possible and include a general summary: normal, mild, moderate, or

severe dilatation; normal, mild, moderate, or severe hypertrophy. Both lin-

ear and volumetric measures are possible with TOE. Use 2D measures

as it is not usually possible to align an M-mode cursor unless transgastric

views are obtained. Start with an overview of the ventricle in all views to

gather an impression of appearance, size, and function.

Linear measures

2D-imaging

• Optimize a transgastric 0° view at the mid-papillary level and record a

loop (Fig. 7.3).

• Identify the end-diastolic frame (widest ventricle). Measure from

the inferior wall endocardial border to the anterior wall endocardial

border in a line at right angles to each wall. Report the left ventricular

end-diastolic diameter. Scroll through to identify the end-systolic frame

(smallest ventricle) and use the same technique to measure the left

ventricular end-systolic diameter.

• M-mode, although not usually done, is technically possible in this view.

• The 2-chamber 80° view gives another window to measure left

ventricular diameters from anterior to inferior walls (Fig. 7.2).

• Left ventricular hypertrophy can be assessed with measures of wall

thickness from the transgastric 2D images at end-diastole in the

septum and posterior wall.

Volumetric measures

Simpson’s method

Simpson’s method of discs can be used if the oesophageal views allow

planes to be set up through the apex. It relies on a good 4-chamber 0°

view that is not foreshortened.

• In the 4-chamber 0° view optimize an image of the left ventricle, with

clear endocardial border and enough depth to include the apex.

• Record a loop. Trace around the border in diastolic and systolic

frames to obtain left ventricular end-diastolic and end-systolic volumes.

• Measure left ventricular length from apex to middle of mitral valve in

the same view to obtain left ventricular long axis.

• For biplane measures repeat the process using an optimized

2-chamber 80° view.

Area-length equation

This method (b p.200) can be used based on a transgastric 0° short axis

mid-papillary level view.

Mass

All the equations and models from TTE (b p.210) can be applied. Ideally

use the transgastric 0° view (equivalent to parasternal short axis). For

measurements based on apical 4- and 2-chamber views use the respective

4-chamber 0° and 2-chamber 80° views. Transoesophageal evaluation is

reasonably accurate, but tends to report slightly higher left ventricular

mass.

480

CHAPTER 7 Transoesophageal chambers and vessels

Left ventricular function

Assessment of left ventricular function with TOE is often needed in the

context of Intensive Care or intraoperatively. Assessment has clinical

importance and should be as comprehensive as possible. Minimal re-

quirements are: left ventricular size and shape; systolic function including

regional differences. Diastolic function assessment from transmitral and

pulmonary vein flow is possible.

Global systolic function

As with transthoracic imaging an eyeball assessment of function is often

used and quoted as normal, mild, moderate, or severe impairment. However,

a visual gauge should, when possible, be backed up by quantification. Use

the same equations as for transthoracic imaging (b p.226) based on the

equivalent measures. The transoesophageal views for measurement of left

ventricular diameters are the 4-chamber 0°, 2-chamber 80°, and transgas-

tric views. Left ventricular diameters in transgastric views are measured

from anterior wall to inferior wall in a line perpendicular to the long axis

of the ventricle, at the junction of the basal and middle thirds of the long

axis. Left ventricular volumes are traced as for transthoracic imaging—

with care to avoid using foreshortened images. Doppler-based measures

e.g. dP/dT (b p.232) can be used from the oesophageal views of mitral

regurgitation.

Regional systolic function

The usual requirement for regional assessment is to determine wall move-

ment in coronary artery territories (Fig. 7.4). The standard 16-segment

model can be applied to transoesophageal images and technically wall mo-

tion scores are possible although not normally quoted.

Wall motion

• Use 4-chamber 0°, long axis 135°, 2-chamber 80°, and transgastric

0° views. Avoid foreshortening. Endocardial border definition is usually

very good.

• Look at the segments and decide whether normal, hypokinetic

(excursion <5mm), akinetic (excursion <2mm), or dyskinetic

(endocardium moves out in systole). If you are unsure look for

thickening >50% between diastole and systole. If present report as

normal or hypokinetic.

• Remember, most commonly:

• Left anterior descending artery supplies: mid and apical septum

and lateral wall in 4-chamber 0° view; anterior wall and apex in

2-chamber 80° view, and septum and apex in long axis 135° view.

• Left circumflex artery supplies: basal and mid segments of posterior

(inferolateral) wall in long axis 135° view and basal lateral wall in

four chamber 0° view.

• Right coronary artery supplies: inferior wall in 2-chamber 80° view

and basal septum in 4-chamber 0° view.

• Transgastric short axis view has right coronary territory nearest

the probe, left anterior descending territory in the far field, left

circumflex territory supplying the posterior wall (on the right).

482

CHAPTER 7 Transoesophageal chambers and vessels

Left ventricular ranges (Table 7.1)

Table 7.1 Left ventricular ranges in women1

Normal

Mild

Moderate

Severe

LV dimension

LV d diameter, cm

3.9-5.3

5.4-5.7

5.8-6.1

>6.1

LV d diameter/BSA, cm/m2 2.4-3.2

3.3-3.4

3.5-3.7

>3.7

LV d diam/height, cm/m

2.5-3.2

3.3-3.4

3.5-3.6

>3.7

LV volume

LV d vol, mL

56-104

105-117

118-130

>130

LV d vol/BSA, mL/m2 35-75

76-86

87-96

>96

LV s vol, mL

19-49

50-59

60-69

>69

LV s vol/BSA, mL/m2

12-30

31-36

37-42

>42

Linear method: fractional shortening

Endocardial, %

27-45

22-26

17-21

<17

Mid-wall, %

15--23

13-14

11-12

<11

2D method: Ejection

>54

45-54

30-44

<30

fraction, %

Linear method

LV mass, g

67-162

163-186

187-210

>210

LV mass/BSA, g/m2

43-95

96-108

109-121

>121

LV mass/height, g/m

41-99

100-115

116-128

>128

LV mass/height2, g/m2

18-44

45-51

52-58

>58

Relative wall

0.22-0.42

0.43-0.47

0.48-0.52

>0.52

thickness, cm

Septal thickness, cm

0.6-0.9

1.0-1.2

1.3-1.5

>1.5

Posterior wall thickness, 0.6-0.9

1.0-1.2

1.3-1.5

>1.5

2D method

LV mass, g

66-150

151-171

172-182

>182

LV mass/BSA, g/m2

44-88

89-100

101-112

>112

BSA, Body surface area; d, diastolic; s, systolic.

Bold rows identify best validated measures.

LEFT VENTRICULAR RANGES

483

Table 7.2 Left ventricular ranges in men1

Normal

Mild

Moderate

Severe

LV dimension

LV d diameter, cm

4.2-5.9

6.0-6.3

6.4-6.8

>6.8

LV d diameter/BSA, cm/m2 2.2-3.1

3.2-3.4

3.5-3.6

>3.6

LV d diam/height, cm/m

2.4-3.3

3.4-3.5

3.6-3.7

>3.7

LV volume

LV d vol, mL

67-155

156-178

179-201

>201

LV d vol/BSA, mL/m2

35-75

76-86

87-96

>96

LV s vol, mL

22-58

59-70

71-82

>82

LV s vol/BSA, mL/m2

12-30

31-36

37-42

>42

Linear method: fractional shortening

Endocardial, %

25-43

20-24

15-19

<15

Mid-wall, %

14-22

12-13

10-11

<10

2D method: Ejection

>54

45-54

30-44

<30

fraction, %

Linear method

LV mass, g

88-224

225-258

259-292

>292

LV mass/BSA, g/m2

49-115

116-131

132-148

>148

LV mass/height, g/m

52-126

127-144

145-162

>163

LV mass/height2, g/m2

20-48

49-55

56-63

>63

Relative wall

0.24-0.42

0.43-0.46

0.47-0.51

>0.51

thickness, cm

Septal thickness, cm

0.6-1.0

1.1-1.3

1.4-1.6

>1.6

Posterior wall

0.6-1.0

1.1-1.3

1.4-1.6

>1.6

thickness, cm

2D method

LV mass, g

96-200

201-227

228-254

>254

LV mass/BSA, g/m2

50-102

103-116

117-130

>130

BSA—Body surface area; d, diastolic; s, systolic.

Bold rows identify best validated measures.

Reference

1 Recommendations for chamber quantification: A report of the American Society of

Echocardiography Guidelines and Standards Committee and the Chamber Quantification

Writing Group, developed in conjunction with the European Association of Echocardiography.

J Am Soc Echocardiogr 2000; 18:1440–63.

484

CHAPTER 7 Transoesophageal chambers and vessels

Right ventricle

The right ventricle is more difficult to see with TOE than transthoracic

imaging because it lies distant to the probe. However with an appropriate

combination of views it is possible to make a reasonable assessment of

right ventricular size and function. Briefly the anatomy consists of a free

wall and the interventricular septum. The cavity is crescent-shaped and

wrapped around the left ventricle. Inflow is through the tricuspid valve and

outflow through the pulmonary valve.

Normal findings

Views

• The key views are: 4-chamber 0° view and short axis 50-80° view

(right ventricular inflow/outflow view) (Fig. 7.5). These can be

supplemented by transgastric 90° long axis view with the probe

rotated clockwise away from the left ventricle.

Findings

• 4-chamber 0° view: rotation to the right focuses on the right atrium

with the right ventricle furthest from the probe. The right ventricular

free wall and septum can be seen. This view permits some assessment

of size although the right ventricle is often foreshortened.

• Short axis 50-80° view: this is also known as the right ventricular

inflow/outflow view and allows assessment of the more basal areas

of the right ventricle free wall, as well as, the tricuspid and pulmonary

valves.

• Transgastric 0° view: this permits a short axis view through the left

ventricle. The right ventricle will be seen wrapping around the left

ventricle (equivalent to a parasternal short axis). This view can be used

to look for septal motion to assess right ventricle overload.

• Transgastric 90° view (right ventricle): rotating the probe away from the

standard left ventricle view may demonstrate the right ventricle. The

tricuspid subvalvular apparatus is visible.

486

CHAPTER 7 Transoesophageal chambers and vessels

Right ventricular size

The complex shape of the right ventricle makes assessment complex and

it may be difficult to support a qualitative impression with quantitative

measures. Assessment is similar to transthoracic imaging (b p.264). Use

several views and comment on wall thickness, cavity size, and outflow

tract size (Fig. 7.6).

Wall thickness

• Use 4-chamber 0° view and comment on thickness of the free wall

at the level of the tricuspid valve chordae tendinae. Do not include

epicardial fat or coarse trabeculations in the measurement.

Cavity size

Qualitative

• Use 4-chamber 0° view and look at mid-cavity diameter. Right

ventricular size is normal if <2/3 left ventricular size, mildly dilated if

slightly smaller than left ventricle, moderately dilated when the same

size, and severely dilated if larger than the left ventricle.

• Alternatively, look at the apex and report as mildly dilated if >2/3 of

the way to the left ventricular apex, moderately dilated if it reaches

the left ventricular apex, and severely dilated if it extends past the left

ventricle.

Quantitative

• Use the 4-chamber 0° view optimized to avoid foreshortening.

Measure right ventricular length, tricuspid annulus diameter, and mid

cavity diameter (Table 7.3).

• Use right ventricular inflow/outflow 80° view to measure right

ventricular outflow diameter, pulmonary valve diameter, and pulmonary

artery diameter.

488

CHAPTER 7 Transoesophageal chambers and vessels

Right ventricular function

The right ventricle contracts in both the long and short axis. The long axis

assessment of the free wall is the easiest way to gauge right ventricular

function.

Assessment

• Use a 4-chamber 0° view.

• Make a qualitative judgement of global function as mild, moderate, or

severe impairment based on whether there is less than the accepted

25mm movement of the tricuspid annulus towards the apex but not

a major reduction in movement (mild), no movement (severe), or

something in between (moderate).

• If you want to quantify the global assessment, measure right ventricular

length in diastole and systole and calculate fractional shortening:

RV diastolic length − RV systolic length

RV length in diastole

(normal is >35% fractional shortening)

• For regional assessment look at the basal, mid, and apical segments

of the free wall in the same 4-chamber view and report them as

hypokinetic, akinetic, or dyskinetic. As with the left ventricle you

should be able to see right free wall thickening to corroborate a

statement of normal or hypokinetic motion.

RIGHT VENTRICULAR RANGES

489

Right ventricular ranges (Table 7.3)

Table 7.3 Right ventricular ranges

Normal Mild

Moderate

Severe

RV dimension

Basal RV diameter, cm

2.0-2.8

2.9-3.3 3.4-3.8

>3.8

Mid RV diameter, cm

2.7-3.3

3.4-3.7 3.8-4.1

>4.1

Base-apex length, cm

7.1-7.9

8.0-8.5 8.6-9.1

>9.1

RVOT diameter

Above aortic valve, cm

2.5-2.9

3.0-3.2 3.3-3.5

>3.5

Above pulmonary valve, cm

1.7-2.3

2.4-2.7 2.8-3.1

>3.1

PA diameter

Below pulmonary valve, cm

1.5-2.1

2.2-2.5 2.6-2.9

>2.9

RV area and fractional area change

RV diastolic area, cm2

11-28

29-32 33-37

>37

RV systolic area, cm2

7.5-16

17-19 20-22

>22

Fractional area change, %

32-60

25-31 18-24

<18

In relation to Fig. 7.6 apical 4-chamber view: basal RV = RVD1, mid RV = RVD2, base-apex =

RVD3.

In relation to Fig. 7.6 parasternal short axis view: aortic valve to free wall = RVOT1, level of

pulmonary valve = RVOT2, pulmonary artery = PA1.

490

CHAPTER 7 Transoesophageal chambers and vessels

Left atrium

The transoesophageal probe lies directly behind the left atrium and pro-

vides excellent views of inflow from all pulmonary veins, outflow across

the mitral valve, left atrial appendage, and atrial septum. Any left atrial

masses are therefore seen much better with transoesophageal than trans-

thoracic imaging.

Normal findings

Views

• The key views are: 4-chamber 0° view, 2-chamber 75° view, long axis

135° view, and bicaval 110° view.

• Further views are needed to look at the pulmonary veins (b p.494).

Findings

• 4-chamber 0° view: the left atrium lies directly in front of the probe and

may allow measurements of left atrial size.

• Long axis 135° view: again the left atrium lies in front of the probe and

can be measured.

• 2-chamber 75° view: with slight adjustments this is perfect for

assessment of the left atrial appendage.

• Bicaval 110° view: the standard view for assessment of the septum.

Left atrial size

Left atrial size is difficult to assess with TOE because the imaging sector

does not normally include the whole of the atrium. Volumes are therefore

unreliable particularly if the atrium is dilated. Linear measures are possible

but may miss longitudinal changes (Fig. 7.7).

Assessment

• Give a qualitative judgement of size based on size relative to the left

ventricle. If the left atrium entirely fits into the 4-chamber 0° view it

is likely to be small. If it appears similar in size to the left ventricle it is

probably severely dilated. There may be supportive qualitative changes

of dilatation, such as spontaneous contrast to suggest slow blood

movement in a large cavity.

• Use quantitative measures of area in the 4-chamber 0° view if the

boundaries of the left atrium can be seen. Trace around the border to

estimate left atrial size and use equations as for transthoracic imaging

(b p.280).

• Simple linear measures are usually sufficient in the long axis 135° view

or short axis 50° view. Measure the distance between the probe and

the left atrial wall by the aortic valve. Remember that quantitative

measures are likely to be unreliable and should be interpreted

taking into account other echocardiographic findings and qualitative

assessment of atrial size.

492

CHAPTER 7 Transoesophageal chambers and vessels

Left atrial appendage

The left atrial appendage is the most common site for left atrial thrombi in

at risk patients, e.g. those with atrial fibrillation, and is therefore of great

clinical relevance, for instance when planning cardioversion or looking for

source of emboli.

Normal findings

Views

• The key view is the 2-chamber view (Fig. 7.8).

• However, the left atrial appendage can have a variable shape so this

key view will need to be adjusted in patients being assessed for cardiac

source of emboli, if the left atrium is enlarged or atrial fibrillation is

found. Once the left atrial appendage is spotted in the 2-chamber

view, adjust the scan angle and move the probe up and down to scan

through the whole appendage.

• It can be useful to study the appendage at ~90° to this view to see the

pectinate muscles in more detail. The scan plane can be rotated to

~140° while maintaining the appendage in the centre of the image.

Findings

• 2-chamber view: the left atrial appendage lies on the right, curving

around the edge of the mitral valve. Parallel to the appendage and

nearer the probe is the left upper pulmonary vein. The appendage and

vein are separated by a bright ridge of tissue known as the warfarin or

coumadin ridge. This can accumulate fat and may appear bulbous.

Assessment

To assess the appendage:

• Identify the appendage (in some people it can be absent or have been

removed/tied/stapled during cardiac surgery).

• Scan through at different planes to identify shape, orientation and

number of lobes (usually one lobe but bilobed appendages occur in

around 10%). Retroverted appendages (pointing towards the probe)

can occur. Inverted appendages are a rare complication of surgery and

appear as a mobile mass in the left atrium below the pulmonary vein.

• Look for evidence of thrombus or rarely tumours. Differentiate

abnormal masses (e.g. thrombus) from pectinate muscles normally

present in the appendage. Thrombus is normally associated with low

flow. If it is not clear whether there is a mass, colour flow mapping can

demonstrate flow down to the apex, or left-sided ultrasound contrast

can opacify the appendage (a mass will remain dark).

• X-plane imaging can be very useful to ‘scan’ through the appendage.

• Measure filling and emptying velocities (Fig. 7.8). Place PW Doppler

cursor 1cm into the appendage and record a trace. Normal velocities

are >40cm/s. Low velocities are associated with atrial fibrillation or

atrial stunning and should make you suspicious that there may be a

clot. Less than 20cm/s indicates a higher risk of clots. Atrial flutter

is associated with regular velocities, occurring at a faster rate than

the ventricular rate. Look for spontaneous contrast in the atrium or

‘smoking’ out of the appendage if velocities appear low.

LEFT ATRIAL APPENDAGE

493

Spontaneous contrast

Spontaneous contrast in the left atrium appears ‘smoke-like’. It is classified

as mild or severe (based on a qualitative assessment of quantity) and may

be located in the left atrial appendage, or both appendage and atrium.

Usually spontaneous contrast in the left atrium indicates increased risk

of thrombosis. It is due to sludging of the red blood cells and is found

when intracardiac velocities decrease. In particular, a dilated left atrium

and atrial fibrillation cause spontaneous contrast. Anticoagulation does

not affect spontaneous contrast. The higher the frequency of the trans-

ducer the better spontaneous echo contrast is displayed.

Differentiating pectinate muscle from thrombus

Pectinate muscle

Thrombus

• Strand-like

• Generally rounded

• Can span the appendage

• May fill the appendage

• Adherent

• Adherent or pedunculated

• Not mobile

• Can be mobile

• Often associated with spontaneous

contrast

Warfarin

Left upper

ridge

pulmonary vein

Left atrial

appendage

Pulsed wave Doppler in

appendage

Atrial flutter on ECG

Velocities of >40cm/s

Fig. 7.8 2-chamber view (top) demonstrates prominent left atrial appendage,

warfarin ridge and pulmonary vein. PW trace (bottom) demonstrates velocities in

appendage consistent with atrial flutter. See W Video 7.1, W Video 7.2, W Video 7.3.

494

CHAPTER 7 Transoesophageal chambers and vessels

Pulmonary veins

Normal anatomy

There are normally 4 pulmonary veins that drain blood from the pulmo-

nary circulation to the left atrium—2 on the left (lower and upper) and

2 on the right (lower and upper). They all lie at the back of the atrium.

Variations in anatomy include only 1 pulmonary vein on 1 side, usually

because the upper and lower veins have joined proximally, or significant

differences in the size of each vein.

Normal findings

Views

The transoesophageal probe lies behind the atria between the 4 pulmo-

nary veins. To see all 4 pulmonary veins modifications of standard views

are required. The key views are the 4-chamber 0° view, 2-chamber 75°

view, and bicaval 110° view (Fig. 7.9).

Findings

• 4-chamber 0° view: all 4 veins can usually be tracked down in this

view. Start from the 4-chamber view and rotate to right or left then

advance or withdraw the probe to bring each vein into view. The

upper pulmonary veins on both sides point towards the probe and

are best aligned for Doppler measures. The lower pulmonary veins lie

perpendicular to the probe.

• 2-chamber 80° view: in this view the the left upper pulmonary vein lies

parallel to the appendage, nearer the probe.

• Bicaval 110° view: by rotating the bicaval view the right upper

pulmonary vein can be brought into view as it drains into the left

atrium parallel to the septum and superior vena cava.

How to optimize pulmonary vein views

• 4-chamber 0° view: if the veins are not obvious, colour flow mapping

placed in the near field on the left or right can be used to highlight

the inflow.

• If the veins are seen but not clearly aligned, rotation of probe angle

between 0° and 90° may help to improve the view.

Assessment

Pulmonary veins are often needed for flow assessment relevant to left

atrial pressure, particularly in mitral regurgitation (b p.120). Their anat-

omy may also be relevant to procedures that use the pulmonary veins as

landmarks, such as ablation for atrial fibrillation.

• Comment on whether:

• All 4 are seen or whether there are more or less than 4.

• They are in standard locations.

• There is any discrepancy in size.

• Report pulmonary vein flow patterns.

496

CHAPTER 7 Transoesophageal chambers and vessels

Right atrium

There are good views of the right atrium with TOE because of its relative

proximity to the probe. Right atrial inflow from both superior and inferior

vena cavae as well as coronary sinus are also straightforward to image.

More detailed studies of the right atrial appendage, Eustachian valve and

atrial septum are possible.

Normal findings

Views

• Key views are 4-chamber 0° view and bicaval 110° view.

• A transgastric view is possible with rotation of the probe from a

standard transgastric 90° long axis view of the left ventricle. This will

normally bring into view the right ventricle and with some withdrawal

of the probe may allow views of the right atrium and tricuspid valve.

Findings

• 4-chamber 0° view: equivalent to the apical 4-chamber, rotation of

the probe to the right allows focused study of right atrium and a

qualitative assessment of size.

• Bicaval 110° view: this is the best view to see the whole of the right

atrium with inferior cava draining on the left and superior vena cava on

the right. The right atrial appendage is invariably present just below the

superior vena cava. The Eustachian valve (if present) will be seen at the

ostium of the inferior superior cava usually directed towards the fossa

ovalis. The atrial septum lies parallel to the probe and the fossa ovalis

is usually seen as a ‘dip’ in the middle of the septum. Use this view to

assess the atrial septum.

Right atrial size

• Assess right atrial size qualitatively based on the 4-chamber 0° view

(Fig. 7.10). Judge size relative to the left atrium and right ventricle.

Normally the 2 atria are roughly the same size.

• The simplest quantitative assessment is the linear measure of the minor

axis in a 4-chamber 0° view (linear measure from middle of right atrial

lateral wall to mid atrial septum). Volumes have not been validated but

can be attempted as for transthoracic imaging.

498

CHAPTER 7 Transoesophageal chambers and vessels

Right atrial features

These usually do not represent pathological findings, but may be mistaken

for abnormalities:

Eustachian valve

Best seen in the bicaval 110° view (Fig. 7.11). The Eustachian valve is a

membranous structure originating from the junction of the inferior vena

cava and right atrium. It represents a remnant from fetal circulation where

placental oxygenated blood coming from the inferior vena cava has to

be diverted through the foramen secundum into the left heart. Thus the

blood flow coming from the inferior vena cava hits the fossa ovalis. This

has implications for contrast application via injections into the arm veins:

there is usually a wash-out of contrast close to the fossa, which may impair

contrast passage. Size can be highly variable. Rarely thrombosis or endo-

carditis can be attached to the valve.

Chiari network

The Eustachian valve may reach the interatrial septum and have net-like

perforations. This is a Chiari network (Fig. 7.11). The Eustachian valve

forms from the regression of one of the valves of the sinus venosus and

if this is incomplete a Chiari network is formed. Echocardiographically a

network of small strands may be seen—sometimes with a broad base,

which can be attached to different parts of the right atrium.

Thebesian valve

Like the Eustachian valve this does not represent a real valve. It is a muscle

and/or fibrous band at the orifice of the coronary sinus in the right atrium.

It can be seen in views displaying the orifice of the coronary sinus.

Christa terminalis

Separates the smooth part of the right atrium from the pectinated muscle

of the right atrium. In the bicaval view the christa terminalis is displayed as

a ridge at the junction of the right atrium and superior vena cava. When

pulling back from a 4-chamber view the christa terminalis can be seen as a

bright protrusion of the lateral atrial wall. Further pulling back shows how

this structure continues into the superior vena cava.

Coronary sinus

To see the coronary sinus use a 4-chamber 0° view. Advance the probe

slightly and retroflex slightly to look below the mitral valve. The coronary

sinus should appear across the image draining to the right atrium.

The sinus can enlarge if there is anomalous drainage of a persistent left

superior vena cava. Anomalous drainage can be demonstrated by injecting

agitated saline into a left-sided arm vein. Because the left-sided vena cava

drains into the coronary sinus the contrast comes through the coronary

sinus into the right atrium.

500

CHAPTER 7 Transoesophageal chambers and vessels

Atrial septum

The atrial septum divides the left and right atrium and embryologically has

2 distinct elements—the primum and secundum septum, which fuse after

birth. Abnormal development or closure of the septum is fundamental

to the emergence of septal defects. TOE is uniquely suited to study the

septum because it can be viewed through the left atrium in several planes

suitable for colour flow and continuous wave Doppler, as well as, contrast

studies.

Normal findings

Views

The key views are 4-chamber 0° view, short axis 50° view, bicaval 110°

view (Fig. 7.12).

Findings

• 4-chamber 0° view: in the 4-chamber view the septum is close to the

probe and rotation to the left can be used for an initial assessment.

Atrial septal defects are usually first evident in this view and colour

flow mapping can identify left to right flow patterns. The atrial septum

normally bows slightly towards the right atrium but in ventilated

patients there is a mild systolic bowing towards the left both during

inspiration and expiration. If right atrial pressure exceeds left atrial

pressure it will bows towards the left.

• Short axis 50° view: here the septum extends from the aortic valve ring,

in a line at 10 o’clock. The primum septum is evident closest to the

valve and this view can be used for stable contrast studies.

• Bicaval 110° view: the standard view to study the septum as it lies

parallel to the probe. The fossa ovalis is usually easily seen as a

depression. This view should be used for colour flow and contrast

studies.

Assessment

Assess the septum in all views using 2D. Look for:

• Lipomatous hypertrophy (bright thickening of the septum that spares

the fossa ovalis).

• Septal defects or an appearance of layers in the septum suggestive of a

patent foramen ovale.

• Atrial septal aneurysms. The septum should move by >10mm either

towards right or left atrium.

Then use colour flow over the septum in the bicaval view:

• A septal defect will be seen as interatrial flow. Also, screen for patent

foramen ovale—a small colour flow jet may be seen in the fossa ovalis

into the atrium during a short part of the cardiac cycle.

502

CHAPTER 7 Transoesophageal chambers and vessels

Atrial septal defects and patent

foramen ovale

Requests for TOE in people with suspected atrial septal defects and patent

foramen ovale are usually because:

• There is a high suspicion from transthoracic imaging of a defect.

• The patient is being evaluated for intervention.

• The study is to look for an embolic source.

Assessment

As for transthoracic imaging (b p.288) initial assessment should be with

2D imaging to look for obvious defects, followed by colour flow mapping.

If a septal defect is seen, Doppler can be used to quantify the shunt size.

Finally, agitated saline contrast injections should always be used if the septal

defect or foramen ovale has not clearly been seen.

2D and colour flow mapping

Use all 3 views but in particular the bicaval view. Look for gaps and then

overlay the colour flow to look for flow (most likely to be left to right).

Comment on:

• Defect position including proximity to aortic valve and likely

classification (primum or secundum) (Figs. 7.13 and 7.14).

• Defect size in several directions.

• Direction and timing of flow from colour flow mapping.

• Associated cardiac defects (particularly relevant for primum defects).

Doppler quantification of shunt

See transthoracic imaging (b p.288). Doppler quantification is not normally

needed for patent foramen ovale. Shunt quantification using measurement

of Qp and Qs is often limited with TOE because alignment of the Doppler

beam to flow through the pulmonary valve is difficult. However measure-

ment of the diameter of the pulmonary artery or right ventricle outflow

tract and of the left ventricle outflow tract is more reliable than on trans-

thoracic images. Pulmonary and aortic vti can be determined separately

with transthoracic imaging.

Agitated saline contrast versus colour flow mapping

In patent foramen ovale or septal defects the left-to-right shunt can be

detected by colour flow mapping. In most patients a right-to-left shunt is

present when right atrial pressure increases, for instance during Valsalva

manoeuvre. However, it may be difficult to display these right-to-left

shunts with colour Doppler. In these cases contrast echocardiography is

indicated (b p.506). Contrast echocardiography is also needed, when

colour flow mapping does not reveal a shunt, since contrast echocardi-

ography appears to be more sensitive.

504

CHAPTER 7 Transoesophageal chambers and vessels

Secundum atrial septal defect—device closure

TOE is indicated to guide transcatheter closure of secundum defects. 3D

TOE can provide more detailed assessment of the defect during the in-

terventional procedure. The key features to record before the procedure

to plan closure are:

• Size in different scan planes (many ASDs are not circular!).

• Presence of multiple defects.

• Presence of interatrial septal aneurysm.

• Size of rim of normal tissue between defect and adjacent structures

for device to fit over. In particular look at rim close to aortic valve.

• Assess for thrombus in left atrial appendage.

• Other cardiac abnormalities (must assess pulmonary veins and

ensure a structurally normal heart).

During the procedure monitor and advise on:

• Guidewire position while crossing the defect.

• Defect size for device sizing.

• Positioning of closure device during deployment.

• Residual shunt after closure.

• Development of thrombus.

• Any impingement on valves.

After the procedure and during follow-up look for:

• Device position.

• Residual shunts.

• Clots or other abnormalities on the device.

Primum atrial septal defect

Primum septal defects are usually well displayed with TTE. During a

transoesophageal study the beginning of the defect will be seen at the

hinge-points of the mitral and tricuspid valves, which arise from the same

level. A 4-chamber 0° view is usually ideal. TOE (Fig. 7.15) is useful for

a comprehensive assessment of the pathology, which often includes

defects of the proximal interventricular septum, mitral and tricuspid valve

insufficiency (including cleft anterior mitral leaflet).

Sinus venosus defect

Sinus venosus defects are very difficult to display using transthoracic 2D

echocardiography. A superior sinus venosus defect is best displayed in a

modified bicaval view with the probe slightly rotated to the right. There

will often be communication between the pulmonary vein and the supe-

rior vena cava opposite to the sinus venosus defect. The abnormal drain-

age of the right upper pulmonary vein can also be displayed in a 0° view

pulled back from the standard flour chamber image to show a short axis

view of the superior vena cava and ascending aorta.

Inferior sinus venosus defects are less common and may be associated with

abnormal drainage of the right lower pulmonary vein.

Coronary sinus defects are between the coronary sinus and the left atrium.

Coronary sinus views are needed to display the shunt, which may be dif-

ficult to see.

506

CHAPTER 7 Transoesophageal chambers and vessels

Contrast study for intracardiac shunts

The 3 elements to ensure a good contrast study looking for an atrial shunt

are identical to those for transthoracic imaging (Fig. 7.16). The sedation

with transoesophageal imaging complicates the Valsalva manoeuvre but

does not make it impossible and the manoeuvre must be used.

1. A stable image

The bicaval 110° view aligns the septum across the image and therefore

provides good views of contrast flow. An alternative view is the short axis

50° view at aortic valve level. The Valsalva manoeuvre causes movement

of the heart up and down. The 50° view tends to be more stable with this

movement as the septum is in line with the image plane.

2. Good quality contrast

The contrast should be 8mL of saline, 1mL of air, and (ideally) 1mL of blood

from the patient mixed in 2 connected syringes until ‘frothy’. Use syringes

with locks to avoid them bursting off. Inject rapidly through a venflon

inserted into the right antecubital vein (if the patient is lying on their left

side this arm will not be compressed and be uppermost). This will ensure

the fastest transit of contrast to the heart (ensure the blood pressure cuff

does not inflate on this arm during the procedure). Good contrast should

completely and rapidly opacify the right atrium. Sometimes rapid flow

from the inferior vena cava causes mixing and partitioning of contrasted

and uncontrasted blood in the right atrium. As the inferior vena cava

directs blood at the foramen ovale the mixing tends to keep contrast away

from the septum. If this persists despite fast boluses then an alternative is

to inject contrast via a femoral vein.

3. A good Valsalva

If further studies are needed after rest injections always do the study with

a Valsalva. The critical time is when the patient relaxes, when right-sided

pressures transiently elevate relative to left. The patient takes a breath and

bears down hard. Inject the contrast and when it fills the right atrium tell

them to relax. If there is a shunt a few bubbles appear in the left atrium

and left ventricle within 5 beats of the patient relaxing. If bubbles appear

later this suggests a pulmonary arteriovenous malformation. This proce-

dure is entirely feasible during transoesophageal imaging with a compliant

patient. To improve compliance lighter sedation can be used and/or the

shunt study can be near the end of the examination (as sedation becomes

lighter). Assistance can be given by asking the patient to press against a

hand placed on the stomach.

Image acquisition

Set the system to capture 10 cardiac cycles and start acquisition on con-

trast injection. Look back through the loop searching for bubbles. Repeat

the study with more contrast until you are happy all 3 elements of the

study are perfect.

508

CHAPTER 7 Transoesophageal chambers and vessels

Ventricular septum

The ventricular septum can be difficult to see entirely with transoesopha-

geal imaging and therefore it is not indicated for assessment of the septum.

However, it is normal to assess the septum routinely during a study and

comment if abnormalities are identified incidentally. TOE provides reason-

able views of the proximal septum and can be efficient for membranous

septal defects. More apical defects, as often occur post-ischaemia, are dif-

ficult to see.

Normal findings

Views

The key views are the 4-chamber 0° view and the long axis 135° view

(Fig. 7.17). These can be supplemented by the short axis 50° view to look

at septum around the aortic valve. The transgastric short axis 0° view can

also be useful.

Findings

• 4-chamber 0° view: the septum lies between the left and right ventricle.

With an unforeshortened view it may be possible to see to the apex

but the views are not aligned for colour flow mapping. The view gives

good depiction of the proximal septum. Withdrawal to the 5-chamber

view allows imaging of the septum below the aortic valve.

• Short axis 50° view: with a slight advance of the probe the membranous

and outlet septum just below the aortic valve can be seen.

• Long axis 135° view: this also demonstrates the septum close to the

aortic valve.

• Transgastric view: this gives equivalent information to the parasternal

short axis view and provides information on the muscular (trabecular)

septum in the mid-ventricle.

Assessment

Assess the septum in all views with 2D and then overlay colour flow to

look for defects. If there is evidence of hypertrophy, particularly in the

outflow tract, then colour flow can also be used to look for subaortic

valve flow acceleration.

• If comments on the septum are required then report septal thickness

(this can be measured from transgastric views) and comment on any

irregular thickening of the septum.

• To identify a ventricular septal defect first look in 2D for evidence of a

‘gap’ then use colour flow to identify definite flow across the septum.

If there is a gap measure the size in two different directions/planes.

Finally, if Doppler alignment is possible consider calculation of a shunt.

However, if a septal defect is sufficient to cause major shunts these

can often be seen most easily with transthoracic imaging.

510

CHAPTER 7 Transoesophageal chambers and vessels

Pericardium

TTE usually gives all the information needed to assess the pericardium.

However, the pericardium should be assessed routinely during tran-

soesophageal studies. TOE can be useful in perioperative cardiac patients

to assess localized collections or because of poor postoperative windows.

Assessment of the pericardium should follow the same routine as with

transthoracic imaging.

Normal findings

Views

Part of the pericardium can be seen (and should be assessed) in all views.

Findings

Pericardial surfaces

The surfaces are usually a thin white line around the heart (normal 1-2mm

thick). Transoesophageal imaging is more accurate for assessing thickness

than transthoracic but should not be relied upon.

Pericardial space

The space, if it contains fluid, is a black, lucent area associated with the

pericardial surfaces (normally <0.5cm, although small effusions can have

significant effects post surgery).

Transverse and oblique sinuses

TOE is good for studying the transverse and oblique sinuses. The transverse

sinus lies between left atrium and aorta/pulmonary trunk (Fig. 7.18).

• Use atrio-ventricular short axis 50° view and then long axis 135° view.

• Fluid or haematoma in the sinus appears as space—shaped like a

crescent or triangle—between ascending aorta and left atrium.

Problems with the transverse sinus

To differentiate the space from the left atrium or left atrial appendage

(roof lies in transverse sinus) use colour flow Doppler. There will be no

flow in the sinus. Beware, because of the position of the sinus it can be

mistaken for abscess or cyst or—if containing fat—an atrial mass.

Oblique sinus lies between the pulmonary veins on back of left atrium.

• Use 4-chamber 0° view.

• Fluid or haematoma in sinus appears as a space between left atrium

and the probe tip in the oesophagus.

512

CHAPTER 7 Transoesophageal chambers and vessels

Pericardial effusion

Assessment

Global effusions

• Use all views. Seen well in 4-chamber 0° view or transgastric short axis

90° view (Fig. 7.19).

• Report depth in several different sites and report where the

measurements were made.

• Gauge global effusion on same parameters as transthoracic imaging

(<0.5cm; 0.5-1cm: mild; 1-2cm: moderate; >2cm: large).

• Comment on appearance (fibrin strands, masses, haematoma).

Differentiate between pleural and pericardial fluid by using

descending aorta and left atrium

(as for transthoracic imaging). In

4-chamber view rotate probe to focus on the left ventricle and

descending aorta. Pericardial fluid will pass between aorta and left

atrium (sometimes widening the gap) whereas pleural fluid will extend

to the lateral side of the aorta.

Localized effusions

• Common sites are in oblique sinus behind left atrium or a posterolateral

collection against right atrium or right ventricle.

• Both can be seen in the 4-chamber 0° view.

• Space between probe and left atrium is the oblique sinus collection.

• Rotate probe to focus on right heart. Look at right ventricle and

atrium for evidence of localized compression or collapse from a

posterolateral effusion.

• Use long axis 135° view to check transverse sinus.

Cardiac tamponade

Features of cardiac tamponade can usually be assessed with transthoracic

imaging. If assessment is required during transoesophageal imaging use

the 2D and Doppler parameters as for transthoracic studies (b p.300).

Remember that tamponade is a clinical diagnosis (hypotension, tachycardia

etc.) and echocardiography will only provide supportive evidence.

Problems in ventilated post-surgery/ITU patients

• There will not be the normal respiratory variation in Doppler indices

of mitral and tricuspid inflow and these should not be used. Rely on

2D features.

• Look for right or left ventricular or atrial collapse.

• Look for localized collection compressing left or right ventricle or

atria reducing chamber function.

• With oblique sinus collection look at pulmonary vein flow. Local

compression will reduce flow velocity in vein.

514

CHAPTER 7 Transoesophageal chambers and vessels

Aorta

The close proximity of the oesophagous to the aorta makes transoesopha-

geal imaging ideal for assessment of the ascending and descending thoracic

aorta. Parts of the aortic arch including the origin of the brachiocephalic

vessels can also be visualized. The views allow diagnosis and assessment

of aortic dissection and severity of aortic atheroma. The portability of

transoesophageal imaging also permits assessment of traumatic aortic

trans-section.

Normal findings

Views

The key aortic views are the 50° short axis aortic valve view both at aortic

valve level and withdrawn slightly, the 135° long axis view, and dedicated

descending aorta and aortic arch views (Fig. 7.20). Deep transgastric and

110° long axis transgastric views can be used for alignment of Doppler in

the ascending aorta.

Proximal ascending aorta

• Proximal ascending aorta is best seen in the 50° short axis view with

slight withdrawal of the probe to scan up the aorta. The 135° long

axis view also allows measures of aortic root size. Transgastric views

sometimes allow Doppler alignment through the proximal ascending

aorta.

Aortic arch

• Seen as the last views as the probe is withdrawn in the aortic views

and can be seen in long and short axis.

Descending thoracic aorta

• The descending thoracic aorta can be seen in short (0°) and long axis

(90°) with the dedicated posteriorly-directed aortic views. Advancing

and withdrawing the probe allows scanning of the entire length of the

aorta. This view can help demonstrate descending aortic aneurysm and

atheroma,. Rotation will differentiate artefact from true abnormality,

particularly when dissection suspected.

• Aortic views can also demonstrate the aortic isthmus, and the ostium,

and proximal part, of the left subclavian artery. This landmark is used

to describe extent of dissection or help assess placement of intra-

aortic balloon pumps.

Emergency evaluation of the aorta

In an emergency where aortic dissection is a major indication proceed

immediately to the 135° long axis view. This view shows the aortic

annulus, aortic valve, and proximal ascending aorta with sinuses of

Valsalva and right and non-coronary leaflets of the aortic valve. A proxi-

mal aortic dissection flap or excessive dilatation of the sinus of Valsalva

is therefore readily diagnosed. Pericardial fluid and aortic regurgitation

can also be detected.

516

CHAPTER 7 Transoesophageal chambers and vessels

Aortic size

Proximal aorta

• Make measurements in 2D imaging from mid-oesophageal 135° long

axis view in systole (with valve leaflet tips open to their maximum).

Standard measures are annulus, sinus of Valsalva at aortic leaflet tip

level, sinotubular junction, proximal ascending aorta (Figs. 7.21 and 7.22).

3D TOE to measure aortic annulus

Measurement of the aortic annulus and proximal aorta is of particu-

lar importance in determining suitability of patients for transcutaneous

aortic valve implantation (TAVI) and selecting appropriate prosthesis

size. Use of 3D imaging and the X-plane modality helps ensure true

cross-sectional diameter being measured.

• Either obtain short-axis 50° view of aortic valve and then position

X-plane cursor though centre of valve to obtain true long-axis cut,

or preferably, obtain a full volume 3D dataset of the aortic valve and

post process to get a precise cross section at the different levels.

The key level is at the level of the aortic annulus and measurements

should be taken from hinge point to hinge point. Measurements in 2

axes should also be performed as the annulus is often not circular.

• It is likely that measurement of true orifice (aortic annulus) from 3D

images will become viewed as the standard. 3D measures are often

slightly larger than 2D measures.

Arch and descending aorta

• In aortic short axis 0° view measure aortic diameter at different levels.

Record the distance from incisors (40cm, 35 cm, 30cm) for each

measure. When withdrawn to the aortic arch rotate to 90° to get a

cross-section and measure diameter.

518

CHAPTER 7 Transoesophageal chambers and vessels

Aortic atherosclerosis

Aortic atherosclerosis is easily seen with TOE. Assessment is important

when hunting for embolic source or before surgery for impression of likely

coronary atherosclerotic disease. Risk of embolic events increases incre-

mentally with extent of atheroma and is dramatically higher once plaque

extends beyond 4mm. Severity is strongly associated with risk factors for

atheroma and, incidence and severity of carotid and coronary disease.

Site of atherosclerosis is not always correlated with stroke localization

and presence of atherosclerosis may simply be a marker of generalized

atherosclerosis.

Assessment

Atherosclerosis is seen as wall thickening, irregular plaque, or as ulcerated,

thrombotic, mobile plaque. Significant atherosclerosis increases the risk

for dissection and aneurysm formation.

• In aortic views scan up the descending aorta and aortic arch. Also

assess proximal ascending aorta.

• Measure wall thickness at several sites and in particular at any position

where there are irregularities. Aortic thickness is intima-media

thickness. The wall is seen as 2 white lines separated by a black space.

Intima-media thickness is the thickness of the inner white and black

bands added together (Fig. 7.23).

• Grade atherosclerosis within the different sections of the aorta as mild,

moderate, or severe (Fig. 7.24).

• Normal wall thickness <2mm.

• Mild atherosclerosis wall thickness 2-4mm moderate

atherosclerosis wall thickness >4mm.

• Severe atherosclerosis irregular protruding plaque (Fig. 7.25).

• Comment on specific lesions, such as thrombus or ulcerated plaques,

and comment on location and depth.

AORTA

INTIMA

MEDIA

Fig. 7.23 Measurement of aortic intima media thickness.

520

CHAPTER 7 Transoesophageal chambers and vessels

Aortic dissection

TOE allows diagnosis and serial monitoring of aortic dissection. Diagnostic

utility with experienced operator is good and comparable to other

modalities (sensitivity and specificity >97%).

Diagnosis

• TTE should routinely be performed first as this may be diagnostic and

negate need for TOE.

• For transoesophageal imaging adequate sedation and good technique

are essential. Excessive retching can cause acute blood pressure

rise, which could extend dissection and cause acute haemodynamic

deterioration. Therefore, if concerns particularly if haemodynamic

instability consider performing study in theatre with cardiac surgeon

available.

• Use all aortic views to scan all of aorta in short and long axes

(Fig. 7.26). In short axis, look for an enlarged aorta with a line across

lumen dividing true and false lumens. True lumen is usually smaller.

Colour flow mapping can be used to demonstrate high velocity flow in

the true lumen and no, or slow flow, in false lumen. In long axis views

dissection flap may be seen as a linear mobile structure with motion

independent of the aortic wall. See Table 7.4.

Limitations—false negative and false positive findings

• The distal ascending aorta cannot be assessed by TOE due to

interposition of trachea and left bronchus. Thus pathology in about

5cm in length may be missed. However, isolated dissection in this

location is rare. False negative studies can occur due to localized

root dissection with pericardial haematoma but no false lumen.

• Linear artefacts have to be distinguished from real intimal flaps.

Reverberation is the most frequent source of these artefacts. Strong

backscatter from various tissue-fluid interfaces such as the anterior

aortic valve or Swan-Ganz catheters in the pulmonary artery can

cause linear echoes in the aortic lumen. They are typically found at

double the distance from the transducer compared to the source of

the reverberation. Also mirror artefacts showing a reduplication of

the aortic lumen are possible. A real intimal flap should be visible in

at least 2 planes. See Table 7.5.

• 3D echocardiography is particularly useful in differentiating dissection

flap from artefact: a true flap can be visualized as a sheet, rather than

a linear structure if artefactual.

522

CHAPTER 7 Transoesophageal chambers and vessels

Assessment

If an aortic dissection is diagnosed (Fig. 7.27) or the study is for serial monitor-

ing of a known dissection the objectives of the investigation should be to:

• Perform all standard aortic measures and measure diameter of true

and false lumens at different levels.

• Try and identify start and end of dissection and record positions.

This allows serial monitoring of size and length of dissection. In the

ascending aorta dissections tend be along the greater curvature and in

the descending aorta may spiral around the true lumen.

• Multiple tears may be present and sometimes it is not possible to

locate the entry site with transoesophageal imaging. As you scan

up the aorta use colour flow to identify connections between true

and false lumens (will be seen as colour flow jets). If seen, measure

positions and direction of flow.

• Comment on and quantify aortic regurgitation. Aortic valve

insufficiency can occur due to dilatation of the aortic root, impaired

cusp movement by ring haematoma, impaired cusp support and cusp

prolapse, or prolapse of the dissecting flap into outflow tract.

• Comment on pericardial fluid and evidence of tamponade.

• Assess global and regional left ventricle function in case of coronary

artery involvement. 10% of dissections involve the coronary ostia.

• Use 3D assessment to confirm nature and extent of dissection flap.

Orientate the probe in 2D just above aortic valve in cross section

initially. Look for coronary ostia to confirm or exclude involvement:

this may be better visualized and appreciated in 3D. Perform 3D

colour flow study to look for additional tears, the number and extent

of which may be under-appreciated on 2D imaging.

• When monitoring dissection, review last study and repeat all measures.

Highlight any changes in appearances or size.

Surgery for aortic dissection

Preoperative

If performing echocardiography before Type A dissection surgery:

• Check diagnosis and differentiate between acute dissection, leaking

aneurysm or intramural haematoma. Type and timing of surgery will

vary significantly.

• Look at aortic valve cusps and aortic root. If normal cusps, and

aortic annulus and sinotubular junction normal size, then even if

regurgitation is seen, inter-position ascending aortic graft replacement,

rather than total aortic root replacement, can be considered.

Postoperative

Ensure successful repair and no residual evidence of dissection. If native

valve was preserved, ensure normal valve function.

AORTIC DISSECTION

523

Table 7.4 Differentiating true from false lumen

True lumen

False lumen

Diameter

True < false

False > true

Pulsation

Systolic expansion

Systolic compression

Blood flow

Systolic, antegrade

Reduced

Spontaneous contrast Rare

Frequent

Thrombus

Rare

Frequent, depending on flow

communication

Localization

Inner, anterior contour Outer, posterior contour

Table 7.5 Differentiating intimal flap from artefact

Intimal flap

Artefact

Borders

Definite

Indistinct

Movement

Rapid, oscillatory

Parallel to strong reflector

proximal to artefact

Extension

Within aorta

Beyond aortic wall

Colour Doppler

Homogenous colour

Different colour

on both sides

communicating jets

Sheet like appearance

Linear

Fig. 7.27 3D TOE demonstrating dissection flap in the aorta. See WVideo 7.15.

524

CHAPTER 7 Transoesophageal chambers and vessels

Intramural haematoma

There is debate as to whether aortic intramural haematoma is a discrete

pathological entity or precursor of aortic dissection. Haematoma tends to

occur in older patients with hypertension.

Diagnosis and assessment

• Intramural haematoma is seen as a generalized thickening of the media

without obvious disruption of the intima and no flow communication.

• Wall thickness >7mm suggests haematoma (normal <4mm).

• Can affect any area of aorta. Intramural haematoma in ascending aorta

is usually managed similar to type A dissection.

Differential diagnosis of haematoma is atherosclerotic disease with a pen-

etrating aortic ulcer. Penetrating ulcer is always: associated with heavy

atheroma; predominantly affects descending aorta; intima is irregular with

thickening above the intima. Atherosclerosis is also suggested by inward

displacement of any intimal calcification with homogenous mottled thick-

ening of wall either side of the displacement.

Aortic transection or traumatic aortic

disruption

Usually occurs at aortic isthmus following acceleration/deceleration injury

(e.g. restrained passenger or driver in road traffic accident). Usually other

traumatic injuries.

To differentiate from dissection:

• Transection is disruption of media rather than intima, resulting in

relatively thick flap, usually very mobile, and perpendicular to aortic

wall (aortic dissection is intimal, with thin flap parallel to wall).

• There is usually no thrombus in the false lumen but there may be a

mediastinal haematoma.

• Usually asymmetric aortic shape. >4mm difference in anteroposterior

and longitudinal aortic dimensions (dimensions similar with dissection).

• Colour flow mapping reveals similar velocities on both sides of any

flap, with turbulence around the point of disruption (turbulence

unusual in dissection and usually slower velocities in false lumen).

526

CHAPTER 7 Transoesophageal chambers and vessels

Aortic coarctation

Usually diagnosed from transthoracic assessment of Doppler flow in

suprasternal view. Accurate transoesophageal imaging can be difficult but

images are best obtained by examining the descending aorta at 0° in mul-

tiple sections to identify the isthmus. At level of isthmus, rotate to a 90°

longitudinal view to identify the origin of the left subclavian artery. Look

for irregularity of aortic lumen. Morphology of aortic coarctation is often

complex and further imaging is usually necessary.

Assessment

• Measure size of aorta proximal, distal, and at the coarctation. For

follow-up, post-repair, compare with previous studies to look for

repair dilatation or persistent gradient.

• PW Doppler in long axis aortic views can be used to look for flow

acceleration across a coarctation.

• 3D volume set acquired at level of maximal narrowing can help

appreciate complexity of coarctation.

Sinus of Valsalva aneurysm

A rare, congenital abnormality (<1:1000 patients). Acquired aneurysms

are even rarer and are predominantly due to endocarditis, trauma, syphilis,

or tuberculosis. Often an incidental finding. When symptomatic, rupture

causes chest pain and breathlessness or, with smaller ruptures, more insidious

onset congestive cardiac failure.

Assessment

• Use the 135° long axis view (>95% originate from either right or non-

coronary cusps, both visualized). Aneurysm usually has a wind-sock

appearance blowing in either right atrium or right ventricle.

• 3D imaging from this view can clarify relationship to cardiac chambers

and aid with planning of interventional approach.

• Colour flow mapping will show an aortic to cardiac chamber shunt.

CW Doppler assessment confirms continuous flow.

• Use a 50° aortic short axis view with slight probe withdrawal to level

of coronary sinus to identify coronary arteries and exclude coronary

artery fistula as an important differential diagnosis.

• Haemodynamic effect of a ruptured coronary sinus is best assessed from

size of atria and left ventricle, reflecting extent of volume overload.

Thoracic aortic aneurysm

Thoracic aortic aneurysm is usually suspected on chest X-ray or TTE.

Confirmation can be by CT, magnetic resonance imaging, or TOE

(Fig.

7.28). CT and magnetic resonance imaging have the advantage of

showing the true extent of the aneurysm and clear identification of the

origin of the head and neck vessels, while TOE more accurately delineates

flow patterns within the aneurysm, the presence of thrombus, and the

presence of atherosclerotic debris.

528

CHAPTER 7 Transoesophageal chambers and vessels

Masses

Masses are usually much clearer on TOE than TTE and therefore TOE is

indicated for definition of masses (Fig. 7.29). Abnormal masses are vegeta-

tions or very rarely thrombi or tumours (see b p.326).

Report position, size, and functional effects. Comment on any suspicions

as to the nature of the mass but remember that echocardiography is

unlikely to give the definitive diagnosis.

Differential diagnosis of masses

Like TTE, transoesophageal imaging does not provide a specific tissue

pattern of the tumours (the exception being lipomas). Therefore it is

not possible to differentiate masses (tumours, thrombi, and vegetations)

according to their structure on echocardiography. However there are

associated features, which help to make a diagnosis.

Myxomas

Myxomas are the most frequent cardiac tumours and usually originate

from the fossa ovalis of the interatrial septum. They also may be found in

other chambers.

Fibroelastoma

Fibroelastoma are mobile tumours on the upstream side of the aortic

valve (rarely mitral valve). In comparison to vegetations there are usually

no other valvular lesions.

Lipomatous interatrial hypertrophy, lipoma in the tricuspid ring

These lipomatous changes have a characteristic high density appearance

but do not result in acoustic shadowing like calcification.

Thrombi

Thrombi are usually associated with reduction in blood flow (atrial fibrilla-

tion, dilated heart chambers, altered or artificial valves or atheroma)

Exceptions to this principle are thrombi associated with coagulopathy and

left ventricular non compaction or on aortic atherosclerosis.

Vegetations

Vegetations are associated with other clinical signs of endocarditis

(e.g. raised inflammatory markers, positive blood cultures).

If the study is for benign or malignant tumours, and there is suspicion of

an extracardiac tumour, consider whether there might be oesophageal

involvement. If this is possible then consider an endoscopy or other

imaging before performing transoesophageal imaging.

530

CHAPTER 7 Transoesophageal chambers and vessels

Cardiopulmonary bypass and coronary

artery surgery

If cardiopulmonary bypass is used for coronary artery surgery in a patient

with normal left ventricular function and no significant valve disease, it

remains a matter of debate whether intraoperative TOE is used routinely.

However, a comprehensive study performed before establishing cardiop-

ulmonary bypass, provides a comparison for postoperative studies in par-

ticular in patients with suboptimal target vessels and challenging grafting.

Indications

• TOE is strongly indicated in coronary artery surgery complicated by:

severe cardiac dysfunction; significant ischaemic mitral regurgitation;

large left ventricular aneurysm; mural thrombus; left ventricular

remodelling (Dor procedure); recent myocardial infarction; ischaemic

ventricular septal defect; requirement for left ventricular assist device

support post surgery.

• TOE should be used when a patient preoperatively has mild to

moderate aortic or mitral valve disease to determine whether valve

surgery is also required. Postoperative echocardiography is required to

assess cardiac function and valve performance whether the valve was

operated on or not.

Coming off bypass

Start monitoring with transoesophageal imaging soon after the aortic

cross clamp is removed. Monitor de-airing of the left heart and aorta and

then watch to ensure restoration of cardiac function. After the patient is

weaned off bypass, ensure stable systemic haemodynamics (i.e. systolic

blood pressure >90-100mmHg, adequate left ventricular filling) then assess

effectiveness of surgery. For all surgery, determine global and regional

cardiac function using standard techniques. If global cardiac dysfunction

develops consider:

• Was there satisfactory myocardial preservation, in particular with

concomitant coronary artery disease?

• Was there a large amount of air emboli into a coronary (particularly

the right as this is uppermost in the supine patient)? Usually causes

severe right, and some left, ventricular failure with significant

tricuspid and mitral regurgitation. Further cardiopulmonary bypass

may be required to wash out air emboli. Monitor recovery with

echocardiography.

• Is there insufficient flow in the bypass grafts (kinking, sutures, etc.)

causing regional wall motion abnormality?

CARDIOPULMONARY BYPASS AND CORONARY ARTERY SURGERY

531

Failure to wean off bypass

A possible urgent call for TOE is to evaluate a patient who has failed

to come off bypass following surgery. Ensure you are familiar with what

surgery is being performed and what the preoperative investigations and

transoesophageal findings were i.e. valve disease, left ventricular func-

tion, and degree of coronary disease. Although there could be many

causes look for:

• Massive mitral or aortic regurgitation due to prosthesis failure

• Acute right ventricular failure due to air emboli (the right coronary

artery is particularly prone to air emboli because of its proximal

position and therefore ‘upper’ position in the supine patient).

Left ventricular failure due to intraoperative myocardial infarction. This

could be due to concomitant coronary disease without sufficient coro-

nary protection or surgical injury (to a coronary ostia in aortic surgery

or the circumflex coronary artery in mitral surgery). Check regional wall

motion abnormalities as a guide to which artery may be affected. Look

at coronary ostia lumen size and flow in short axis views.

532

CHAPTER 7 Transoesophageal chambers and vessels

Off-pump coronary artery bypass

Transoesophageal monitoring can be useful in off-pump coronary artery

bypass graft surgery to monitor cardiac function and potential mitral

regurgitation. Beware of the following aspects of off pump surgery:

• Imaging of left ventricular wall motion is limited by the stabilizer

apparatus, which tethers the adjacent myocardium.

• During right coronary artery and circumflex grafting major

displacement of the heart does not allow reliable imaging.

• Distortion of the heart can also cause transient mitral regurgitation or

increase in right atrial pressure and a shunt via a patent foramen ovale.

• It is best to restart imaging after completion of anastomoses and

release of the stabilizer.

• For a short period after the anastomosis regional wall motion

abnormalities are seen, representing stunned myocardium. If wall

motion abnormalities are persistent, graft patency should be checked.

Ischaemic mitral regurgitation

Ischaemic mitral regurgitation is regurgitation due to incompetent mitral

valve systolic coaptation with normal valve leaflet structure, in the pres-

ence of ischaemic heart disease. Commonly due to tethered mitral leaflets

after basal posterior myocardial infarction, combined with mild to mod-

erate mitral annulus dilatation. Less frequently due to papillary muscle

dysfunction or detachment.

• It is usually present before surgery. In this case imaging has to

assess the severity to decide on the need for mitral valve repair or

replacement. To plan surgery (approach, mitral valve ring size etc.)

measure leaflet tethering distance (distance between posterior

papillary muscle and mitral valve posterior annulus) and mitral valve

annulus diameter.

• Ischaemic regurgitation may also evolve during coronary bypass

surgery due to insufficient grafting to the right coronary artery or

diffuse myocardial ischaemia. Ischaemic mitral regurgitation is dynamic

so tends to be less severe during surgery because of the reduced left

ventricular afterload and the general anaesthetic. Moderate to severe

regurgitation on intraoperative echocardiography requires surgical

intervention.

Aneurysm repair

Before and during ventricular aneurysm resection or apex remodelling

(Dor procedure) echocardiography should focus on:

• Presence, mobility, and distribution of mural thrombus.

• Involvement of mitral valve apparatus and papillary muscle.

• Mitral regurgitation caused by surgery.

• Amount and function of residual myocardium.

534

CHAPTER 7 Transoesophageal chambers and vessels

Haemodynamic instability

On the Intensive Care Unit and during intraoperative monitoring TOE

provides a quick and reliable way to investigate the cause of haemodynamic

instability. Haemodynamic instability usually means unexplained hypotension

in some cases associated with unexplained hypoxaemia. TOE provides

information on both intrinsic cardiac causes (e.g. ventricular function,

valve function) and extracardiac factors (e.g. left ventricular preload and

afterload). Assessment should take into account the clinical history and

follow a standard routine to try and exclude common cause (Table 7.6).

Chapter 11 provides information on how to use TTE in this setting.

Hypotension due to hypovolaemia

Hypovolaemia causes reduced left ventricle preload/filling. A simple meas-

ure of preload/filling is the left ventricular end-diastolic area in the short-

axis transgastric view. This view can be used for monitoring during surgery.

It is useful if a baseline area is known (e.g. preoperative or at start of

surgery) in order to judge change from normal filling.

• Hypovolaemia causes a reduced end-diastolic left ventricular volume

and, with preserved left ventricular function, an even greater reduction

in end-systolic volume. This results in a very high fractional area

change.

• If hypovolaemia is diagnosed, the response to fluid therapy should be

monitored. Optimal filling of the left ventricle is achieved when further

volume supplements do not result in further increases in end-diastolic

left ventricular area. Further volume then merely causes increase in left

ventricular end-diastolic pressure.

Hypotension due to reduced peripheral resistance

Reduced peripheral resistance (e.g. due to sepsis) results in much higher

stroke volumes. End-diastolic volume therefore remains normal but the

end-systolic volume is reduced. This again leads to an increased fractional

area change.

Hypotension due to ischaemia

If there is clinical suspicion of myocardial ischaemia it is useful to compare

any new findings to the preoperative assessment of cardiac function. Look

for:

• Left ventricular systolic global and regional function.

• Right ventricular systolic dysfunction. Right ventricular dysfunction

is often associated with right ventricular dilatation, tricuspid

regurgitation, paradoxical septal movement and a decrease in left

ventricular chamber size can sometimes occur.

• True or pseudo-aneurysm and/or right ventricular rupture in those

known to have had an infarct.

• Ischaemic ventricular septal defect or papillary muscle rupture.

• Pericardial effusion or tamponade.

HAEMODYNAMIC INSTABILITY

535

Table 7.6 Conditions causing hypotension. Severe aortic stenosis can

also be associated with hypotension and is identified from changes to

the aortic valve and transvalvular gradient. Aortic dissection can cause

hypotension due to associated pericardial effusions and tamponade,

hypovolaemia or aortic regurgitation

Condition

End-diastolic End-systolic Ejection Cardiac

Associated findings

volume*

fraction** output

Decreased preload

Hypovolaemia

Decreased afterload n

Vasodilation/sepsis

LV dysfunction

Global/regional wall

motion,

rupture

RV dysfunction

(d)

Dilated right heart

thrombus in

pulmonary artery

Tamponade

Effusion

^*Left ventricle end-diastolic and end-systolic areas in the short axis transgastric views may be

used as markers of left ventricle volume.

^**Fractional area change can be substituted for ejection fraction.

536

CHAPTER 7 Transoesophageal chambers and vessels

Unexplained hypoxaemia

Hypoxaemia suggests inadequate lung perfusion. In ventilated patients this

may be a greater than normal need for respiratory support. Cardiac causes

can include right ventricle dysfunction, pulmonary embolism, or right-

to-left shunts. Investigations should also look for primary lung pathology

(e.g. pneumonia with associated sepsis).

Pulmonary embolism

Pulmonary embolism is not easy to diagnose (and can not be excluded)

because large emboli are needed to induce haemodynamic changes or to

be visualized. Helpful features to suggest pulmonary embolism include:

Indirect signs

• Dilated right atrium. Dilated and diffusely hypokinetic right ventricle.

Dilated pulmonary artery. (An increased right ventricle wall thickness

suggests a more chronic problem, e.g. pulmonary hypertension.)

• An increase in tricuspid regurgitation because of raised pulmonary

artery pressure. Judge pressure from the tricuspid regurgitation.

(However, cardiac shock can lead to a normal gradient.)

Direct signs

• Thrombus in the inferior or superior vena cavae, or pulmonary artery.

• There are 2 types of thrombi. Type A are highly mobile and

vermiform. They derive from deep veins and can become trapped in a

Chiari network, tricuspid valve chordae or right ventricle trabeculae.

Type B originate from chamber walls, leads, or prostheses.

• To see the pulmonary artery withdraw the probe slightly from an

aortic 50° view and angulate the probe forward. The right pulmonary

artery can be seen wrapping around the aorta. The left pulmonary

artery is obscured by the bronchus.

Patent foramen ovale

In suspected pulmonary embolism always assess the inter-atrial septum.

High right atrial pressure opens the foramen and can cause significant

right-to-left shunting. With successful treatment of the embolism the

shunt reduces and then disappears. Paradoxical embolism is possible and

sometimes thrombi can be trapped in the septum.

Right-to-left shunt

Right-to-left shunts can be intracardiac or intrapulmonary. Base initial sur-

vey on colour flow mapping of the atrial and ventricular septa. If no shunt

is displayed by colour flow mapping use agitated saline contrast, injected

through a central line.

• If an intracardiac shunt, contrast will pass from right to left atrium, or

from right to left ventricle immediately after arrival in the right atrium.

• If an intrapulmonary shunt, contrast will appear in the left atrium via the

pulmonary veins at least 3 beats after the right atrium.

• If there is a known pre-existing left-to-right shunt this may be turned

into a right-to-left shunt by the type of surgery, ventilation, or a

super-added pulmonary embolism. Positive end-expiratory pressure

ventilation may open a patent foramen ovale in the presence of severe

pulmonary embolism.

538

CHAPTER 7 Transoesophageal chambers and vessels

Mechanical cardiac support

Intra-aortic balloon pump

TOE can be used to identify contraindications to a balloon pump and en-

sure the balloon is correctly placed in the thoracic descending aorta, distal

to the subclavian artery (Fig. 7.30).

Complicating factors

Possible contraindications include: descending aortic aneurysm, moderate

to severe aortic regurgitation, severe atheroma.

Placement

To localize the balloon tip start with an aortic arch view. Try and locate

the left subclavian artery origin then advance the probe until the tip of the

balloon pump comes into view. It should be several centimetres below

the left subclavian artery. The tip appears as a bright mark in the centre of

the aorta, with associated artefacts. If the probe is advanced further the

balloon may be seen deflating and inflating in the aorta.

Left ventricular assist devices

Left ventricular assist devices take blood from a cannula placed in the

left atrium or left ventricle, pass it through an extracorporeal pump, and

then pump the blood back into the circulation via a tube inserted into

the ascending aorta. TOE can help in placement, assessment of device

function, and device weaning.

Complicating factors

Before placement, imaging should be used to identify possible contraindi-

cations and complications.

• Aortic regurgitation may deteriorate after device placement because

of increased backflow into a relatively decompressed left ventricle. In

moderate aortic regurgitation valvular surgery has to be considered

prior to device placement.

• Thrombi within the ventricular cavities may be mobilized by assist

device tubes and should be excluded.

• Aortic atheroma may be dislodged during cannula insertion.

• Right ventricular dysfunction should be assessed in case right

ventricular assistance is required.

• Patent foramen ovale should be identified. Significant right-to-left

shunting can be found after left ventricular assist device placement.

The device significantly offloads the left heart and drops left atrial

pressure, whereas the right atrium remains at a relatively high

pressure.

540

CHAPTER 7 Transoesophageal chambers and vessels

Placement

During placement of a left ventricular assist device use TOE to report to

the surgeon:

Cannulae

• Position of the atrial cannula (should be in centre of atrium). It should

not lie against a wall and be away from the subvalvular apparatus.

• Flow in the cannulae (can be displayed using colour flow mapping).

• Flow pattern in the descending aorta.

• De-airing of the system by observing clearing of bubbles through the

ascending or descending aorta.

Changes to valves and septum

• Patent foramen ovale, which may have been missed pre-placement.

• Presence of tricuspid regurgitation.

• Competence of the aortic valve.

Changes to chamber function

• Whether adequate left ventricle offload is achieved.

• Left atrium filling status and size.

• Right ventricle volume status and contraction.

During use

After placement, TOE should monitor for bleeding and pericardial effu-

sion. This is common during the first 24 hours of support and can cause

cardiac tamponade.

Weaning

On removal, TOE should be used to judge weaning of left ventricle

assist support. The emphasis should be on watching the effect of reducing

support on left ventricular function. The left ventricle should gradually

improve and take over haemodynamic function.

• Monitor response of the left ventricle to resumed volume loading at

both regional and global levels.

• Look at mitral valve competence and systemic haemodynamics.

• Check that improvement in left ventricle function is sustained with

minimal support rather than just a shorted-lived improvement of left

ventricle contraction.

544

CHAPTER 7 Transoesophageal chambers and vessels

Pacing wires and other implants

As well as prosthetic valves a series of other artificial devices will be seen

during transoesophageal studies. Right-sided implants include pacing and

defibrillator wires in the right atrium and ventricle and central lines in the

superior vena cava and right atrium (Fig. 7.32).

Increasingly, percutaneous closure devices are being implanted. Most

commonly these are seen across the atrial septum but can also be posi-

tioned in the ventricular septum or beside prosthetic valves to close para-

prosthetic leaks. Left atrial appendage occluder devices are also implanted

in some centres. Make sure you check the notes before and during the

procedure if there is an unusual feature identified.

548

CHAPTER 8 Intracardiac Echocardiography

Background

• Since its initial use over 30 years ago, intracardiac echocardiography

(ICE) has become increasingly available and important as an alternative

to TOE primarily to guide percutaneous interventions and support

electrophysiological procedures.

• The limitations of the earliest ICE catheters used (poor tissue

penetration and difficult manipulation) have been overcome with

catheters that use lower frequencies (enabling tissue penetration of up

to 12cm) and have better manoeuvrability (Table 8.1).

• ICE provides high-resolution images of cardiac structures which can be

displayed as M- and B-modes, with Doppler (CW, PW, or colour flow

imaging) or reconstructed into 3D (mainly used in research only at the

moment but clinical 3D ICE is not far off now).

• Advantages of ICE over TOE during percutaneous interventions

include clearer imaging, shorter procedure times and the use of local

(rather than general) anaesthesia.

• ICE catheters are for single-use only and the additional cost that this

incurs is the principal disadvantage although this may be offset by the

shorter procedure times, improved patient turnaround, and reduced

personnel costs.

• ICE is ideal for imaging PFO closures as these procedures can now be

performed as a day case under local anaesthetic with total procedure

times of around 30min.

• As visualization of the septum is so accurate, ICE has also been

shown to reduce the need for fluoroscopy when compared to

TOE-guided procedures with a reduction in radiation doses used,

shorter procedure times, and shorter hospital stays.

• ICE catheters are not inserted ‘over a wire’ and are relatively stiff so

careful intravascular and intracardiac manipulation is required to avoid

perforation.

Indications

• Percutaneous ASD/PFO closure.

• Percutaneous closure of perimembranous ventricular septal defects.

• Balloon mitral commissurotomy.

• Left ventricular or atrial septal pacing.

• Septal ablation for hypertrophic cardiomyopathy.

• Guiding the biopsy of cardiac masses.

• Pulmonary valvuloplasty.

• Guiding transseptal access during electrophysiological procedures.

• Catheter ablation of arrhythmias for defining anatomy.

• Paravalvular leak closure.

• Left atrial appendage occlusion.

• Transcatheter aortic valve implantation.

550

CHAPTER 8 Intracardiac Echocardiography

Equipment

Mechanical catheters

• Mechanical transducers have a rotating element (9MHz) which creates

a 360° imaging plane perpendicular to the long axis of the catheter.

• The transducers provide a tissue penetration of around 4cm.

• The main limitations of mechanical catheters are the limited imaging

plane (horizontal only), reduced catheter manoeuvrability (versus

more recent phased-array catheters), and the inability to perform

Doppler studies.

Phased-array catheters

• Phased-array 64-element transducers are able to scan in a longitudinal

plane, creating a 90° sector image.

• Lower range frequencies (5-10MHz) allow better tissue penetration

(up to 12cm).

• Improved manoeuvrability is achieved as the head of the catheter has a

multidirection articulation tip and steering locks can maintain catheter

angulation (Fig. 8.1).

Procedure

Patient preparation

Patient preparation relates to the interventional procedure that is to be

undertaken. Normally this will involve:

• Pre-procedural fasting for 4 hours. An important aspect for ICE is that

the patient should not be dehydrated so give IV fluids if necessary.

• Insertion of a peripheral cannula to allow delivery of sedation if

needed. Both inguinal areas should be prepared and draped.

Catheter preparation

• A connector is used to link the ICE catheter to the ultrasound

machine. The connector is covered in a sterile sleeve then connected

to the ICE catheter. Check the catheter steering mechanism before

use.

Vascular access

• Venous access is usually obtained via the right femoral vein using a

Seldinger technique although the right jugular vein has also been used.

• The catheter is manipulated into the right atrium. Special caution is

needed when manipulating the catheter through the pelvic veins and

fluoroscopy screening is recommended to avoid the catheter catching

on venous branches (Fig. 8.2).

• Sometimes gentle AV steering is needed tortuous vessels.

• Placement of a guidewire through an adjacent sheath can help guide

the catheter into the right heart, or insertion of a longer sheath

(e.g. 12Fr Mullins sheath) to the IVC or right atrium in particularly

difficult cases.

552

CHAPTER 8 Intracardiac Echocardiography

Imaging planes

With the use of a phased array catheter, all cardiac anatomical landmarks

can be imaged with the probe positioned either in the right atrium or right

ventricle. A structured system of steering and manipulation of the catheter

is recommended to allow a detailed thorough examination, improving op-

erator orientation and recognition of landmarks.

Standard view

The ‘standard view’ (Fig. 8.3) is achieved with the ICE probe sited in the

mid-right atrium and with the scan plane facing anteriorly.

• This provides excellent views of the right atrium, right ventricle, and

tricuspid valve.

• Withdrawing the catheter to the inferior right atrium brings the

Eustachian ridge and the tricuspid valve isthmus into view.

What do you see?

• Right atrium.

• Right ventricle.

• Tricuspid valve.

Atrial septum

Slowly advancing the catheter whilst gently retro-flexing and rotating the

catheter tip manipulates the probe towards the intra-atrial septum, high-

lighting the fossa ovalis (Fig. 8.4).

• In order to avoid foreshortening some left-to-right manipulation may

be needed.

• Detailed interrogation of the atrial septum and fossa ovalis can

be obtained and, if needed, agitated saline bubble contrast studies

(b p.506) can be performed to assess for the presence of a patent

foramen ovale.

• This position of the catheter for assessment of the atrial septum is

employed for percutaneous septal procedures as it sits in a neutral

position, without interfering with interventional catheters.

What do you see?

• Right atrium.

• Atrial septum.

• Left atrium.

Aortic valve and root

To view the aortic valve in the short axis the catheter tip is retroflexed

and then rotated clockwise towards the aorta (Fig. 8.5).

What do you see?

• Aortic valve.

• Ascending aorta.

• Left ventricle.

554

CHAPTER 8 Intracardiac Echocardiography

Pulmonary veins

The left superior and inferior pulmonary veins can be viewed by increasing

the depth from the atrial septum view (Fig. 8.6). For finer adjustment inferior

angulation may be needed. The right pulmonary veins can be seen by gen-

tle clockwise rotation and superior advancement of the catheter.

What do you see?

• Left and right pulmonary veins.

• If needed, Doppler studies can be performed to analyse the venous flow.

Left atrial appendage

Advancing the catheter towards the atrial septum and rotating clockwise

brings the left atrial appendage into view.

What do you see?

• Left atrial appendage.

• Left ventricle.

• Mitral valve.

Mitral valve and left ventricle

Advancing the catheter towards the atrial septum and rotating clockwise

brings the left atrial appendage and mitral valve into view (Fig. 8.7).

What do you see?

• Left atrium.

• Mitral valve.

• Left ventricle.

Right ventricle

From the initial standard view the catheter can be flexed and gently

advanced towards the tricuspid valve. With further careful manipulation

under fluoroscopic control the catheter can be placed in the right ventricle

(Fig. 8.8). Typically the catheter lies against the septum and rotated to scan

either the right ventricular free wall or the left ventricle.

What do you see?

• Ventricular septum.

• Right ventricular free wall.

• Left ventricular lateral wall.

556

CHAPTER 8 Intracardiac Echocardiography

Atrial septal interventions

Visualization of the interatrial septum and fossa ovalis with ICE allows a

detailed assessment of the size and length of the PFO ‘tunnel’ and additional

information gained on the mobility of the atrial septum (Figs. 8.9 and 8.10).

The ICE catheter is usually quite stable for guiding the percutaneous

closure of PFO and atrial septal defects (ASDs).

Key views

The following steps in sequence allow full assessment of the atrial septum

during atrial septal interventions:

• After advancing the ICE catheter from the inferior vena cava into the

mid-right atrium rotate the probe clockwise. The aorta and LVOT will

initially be seen. Further clockwise rotation will allow visualization of

the lower atrial septum.

• Posterior deflection with continued clockwise (posterior) rotation will

obtain a long axis view of the atrial septum.

• Moving the catheter cranially and caudally shows the entire atrial

septum.

• If appropriate a bubble contrast study can be performed from this

position to document the presence of a PFO.

• From here, the left upper and lower pulmonary veins can be visualized

with the aid of Doppler colour flow.

• Clockwise rotation of the catheter allows visualization of the right

upper and lower pulmonary veins.

• Gentle anterior flexion and clockwise rotation shows the superior

vena cava.

• With anterior and lateral movement of the catheter tip a short axis

view of the atrial septum is obtained.

558

CHAPTER 8 Intracardiac Echocardiography

Balloon sizing

• The long axis view of the atrial septum usually provides the best

imaging plane for balloon sizing (Fig. 8.11).

• Colour flow imaging is used whilst obtaining multiple views of the

inflated balloon to demonstrate complete coverage of the defect.

• The balloon size can be obtained from anterior and lateral fluoroscopy

images.

Device deployment

• Following sizing, a sheath is positioned over a stiff wire into the left

upper pulmonary vein through which the device is delivered.

• After device insertion, prior to and following deployment the adjacent

structures should be interrogated to ensure that there was no

encroachment of the device on the atrioventricular valves, the right

pulmonary vein or the inferior or superior vena cava (Fig. 8.12).

Evaluation of the defect during atrial septal intervention

During atrial septal intervention the key views will allow ASD size

estimation by measurement of the distance between the defect to the:

• Aortic valve (superior-anterior rim).

• Coronary sinus (posterior rim).

• Mitral valve (inferior-anterior rim).

• Inferior vena cava (inferior-posterior rim).

Special care should be taken to also evaluate the relationship of the

defect to:

• Pulmonary veins.

• Atrioventricular valve.

• Aortic root.

560

CHAPTER 8 Intracardiac Echocardiography

Electrophysiological interventions

The advantage of accurate visualization of anatomical structures means that

ICE can be used to guide interventional physiology. Clinical applications of

ICE during electrophysiology include:

Transseptal puncture guidance

• During electrophysiology transseptal puncture is very important to

obtain access into the left atrium for ablation procedures.

• Historically fluoroscopy has been used to guide the transseptal

puncture. Here, the anatomical structures are not displayed directly

and the needle puncture is guided by the movement during pullback

from the superior vena cava and position in the cardiac shadow

relative to a catheter in the aortic root.

• ICE offers the opportunity to guide the transseptal puncture by

directly visualizing the needle tip within the fossa ovalis region.

By detailing the relevant anatomy, ICE can offer the operator further

information when confronted with anatomical variations (atrial septal

aneurysm or lipomatous hypertrophy of the atrial septum, etc).

• Colour flow Doppler can also be helpful to identify the puncture site

should the interventional catheter fall back into the right atrium.

Catheter ablation of arrhythmias

The detailed anatomical orientation provided by ICE has the following

advantages during ablation procedures:

• A detailed understanding of the anatomy of the pulmonary veins.

• ICE provides the ability to confirm stable, complete catheter-tissue

contact which ensures more complete ablation and reduces the

incidence of clot formation on the catheter.

• To identify the presence of thrombus within the left atrial appendage.

• To confirm the anatomy of the oesophagus in relation to the left

atrium, to reduce the possibility of atrio-oesophageal fistula.

• Assists accurate placement of both mapping and ablation catheters.

• Operators are able to prevent tissue overheating (and resultant scar

formation, thrombosis, or stenosis) by delivering ablation therapy until

the onset of microbubble formation, ensuring maximal safety.

• Images acquired using ICE have recently been combined with

3D electrophysiological mapping catheters to provide additional

anatomical information during ablation.

Additional uses

ICE has also been used to guide catheter occlusion of the left atrial

appendage by deploying the ICE catheter in the pulmonary artery via

a long sheath, and to guide transcatheter aortic valve implantation

(see b p.464), utilizing both transvenous and transarterial placement.

Radiological interventions such as fenestration of aortic dissection flaps

can also be guided with the use of 8Fr intra-arterial ICE.

562

CHAPTER 9 Contrast echocardiography

Introduction

Contrast imaging relies on the use of an injected agent that is very echo-

genic in order to increase the brightness of the ultrasound image. Broad

types of contrast used are those that are normally only held in the venous

circulation and then absorbed in the lungs (right-heart contrast agents)

and those that are present in both the venous and systemic circulations

(left-heart contrast agents).

Both right and left contrast agents essentially consist of gas bubbles of

varying size. On the right this is air contained in saline and on the left a gas

in a lipid or albumin shell (Figs. 9.1-9.3).

Right-heart contrast agents

• Right-heart contrast agents such as agitated saline consist of air

microbubbles (of a relatively large size when compared to left-heart

contrast agents). These are short lived and normally diffuse into

the lungs when crossing the pulmonary circulation. The presence

of agitated saline microbubbles in the left heart indicates either the

presence of a right-to-left intracardiac shunt or an arteriovenous shunt

elsewhere in the body, typically in the pulmonary circulation.

• The stability of these bubbles can be improved if the agitation is

performed with blood (<0.5ml in 10ml saline).

• Other agents used because they contain bubbles include Gelofusine®

(gelatine) but have the risk of allergic reaction.

Uses

• To identify the presence of a right-to-left intracardiac shunt due to an

atrial septal abnormality.

• To identify the presence of a right-to-left intrapulmonary shunt.

• To enhance the delineation of Doppler signals, e.g. the use of agitated

saline contrast can provide a better Doppler signal assessment of the

tricuspid valve.

Left-heart contrast agents

• Left-heart contrast agents must be durable and small enough to be

able to cross the pulmonary circulation and pass into the left atrium

following an intravenous injection.

• Left-heart contrast agents comprise a microbubble gas centre with

an outer shell. This makes it durable but also small enough for safe

passage across the pulmonary circulation.

Uses

• To improve LV endocardial border definition in order to:

• improve image quality and the percentage of wall segments visualized

• improve the confidence of interpretation of wall motion

abnormalities during stress imaging.

• improve accuracy of ventricular volumes and EF measures.

• To improve LV cavity opacification to detect pathology e.g. thrombus,

apical HCM, LV non-compaction.

• To enhance the delineation of Doppler signals.

• To assess myocardial perfusion.

564

CHAPTER 9 Contrast echocardiography

Specific contrast agent preparation

Left-heart contrast agents

SonoVue® (Bracco International BV)

• Structure: a phospholipid shell filled with sulphur hexafluoride (SF6).

• Preparation and storage: it is reconstituted with sodium chloride

(Fig. 9.4). The authors recommend that the contrast is constituted

within a few minutes of injection and to agitate the vial before each

injection is withdrawn. If given as an infusion it needs to be agitated in

a special agitating pump during delivery.

• Bolus: recommended dose is 2.0mL. However, the dose derives from

studies using fundamental imaging, which should be avoided. For

harmonic imaging bolus injections of 0.2-0.4mL are adequate. The

bolus should be followed by a 3-5mL bolus of 0.9% sodium chloride or

5% glucose. Total dose should not exceed 1.6mL.

• Infusion: for SonoVue® a special agitation pump is used (Fig. 9.5). For

stress studies 2 vials should be drawn up into the syringe. The rate of

infusion should be initiated at 0.8mL/minute, but titrated as necessary

to achieve optimal image enhancement (the range is 0.6-1.2mL/min).

Optison® (Amersham)

• Structure: Optison® (Amersham) an albumin shell containing perflutren

gas.

• Preparation and storage: it comes in a vial that requires reconstitution

and manual agitation. It is then drawn up into a 2mL or 1mL syringe.

A second needle is used to vent the vial (this can be removed if

repetitive doses are withdrawn. The authors recommend that the

agent is reconstituted directly before injection and the vial agitated

before each dose is withdrawn. It should be stored in a refrigerator

between 2-8°C.

• Dose and administration: the recommended dose is 0.5-3.0mL per

patient injected into a peripheral vein. However, that dosage derives

from studies using fundamental imaging, which should be avoided. For

contrast-specific imaging modalities bolus injections of 0.2-0.4mL are

adequate. Total dose should not exceed 8.7mL. The bolus should be

followed by a 3-5mL bolus of 0.9% sodium chloride or 5% glucose.

566

CHAPTER 9 Contrast echocardiography

(Bristol Myers Squib)

• Structure: Luminity® is composed of lipid-encapsulated perflutren

microspheres. The spheres are between 1-10 micrometres in

diameter.

• Preparation and storage: it should be stored in a refrigerator at 2-8°C

until activated. It needs to be activated by a mechanical shaking device

(Vialmix) and then can be used for up to 12 hours (although if left

standing for more than 5min it requires 10sec of shaking by hand

before further use). It can be reactivated once more within 48 hours.

• Dose and administration: recommended bolus dose is of 0.1-0.4mL

followed by a bolus of 3-5mL of 0.9% sodium chloride or 5% glucose.

Diluting 0.3mL in 10mL saline (0.9% sodium chloride) and injecting

1-2cc is an alternative and provided good contrast in IE33 scanners.

Total dose should not exceed 1.6mL. The recommended intravenous

infusion is of 1.3mL Luminity® added to 30ml of 0.9% sodium chloride.

The rate of infusion should start at 1mL/min and be titrated to achieve

optimal image enhancement (not to exceed 10mL/min).

Right-heart contrast agents

• Agitated saline contrast can be used to demonstrate the presence

of right-to-left shunts across the atrial septum, or to improve the

Doppler envelope when examining the tricuspid valve (Fig. 9.6).

• Insert a cannula ideally into the right antecubital fossa.

• Attach a 3-way tap to the cannula.

• Obtain 2 10mL Luer lock syringe. In one syringe draw up 9mL of saline

and 1mL of air. 0.5mL of the patient’s blood can also be drawn up.

• Ensure both Luer lock syringes are firmly attached to the cannula and

force the mixture back and forth between the syringes until frothy.

568

CHAPTER 9 Contrast echocardiography

Administration of contrast agents

Left-heart contrast agents

• Patient preparation requires insertion of an intravenous cannula usually

into an antecubital vein and its connection to a 3-way-tap or small-

bore Y connector. Ultrasound contrast agents can be injected through

this line by bolus injection or an infusion.

• The use of smaller diameter cannula should be avoided as the bubbles

from the contrast will be subjected to a large pressure drop as the

fluid exits the tip of the lumen. The faster the injection and the smaller

the diameter of the lumen, the larger the pressure drop and there is

increased chance of damage to the contrast bubbles.

Bolus injection

• Slow bolus injections (0.2mL) of all agents (SonoVue®, Luminity®, and

Optison®) can be used followed by a slow 5mL saline flush over 20s.

However, these are not as controllable or reproducible as infusions.

• Agitate the contrast immediately before injection slowly and withdraw

the contrast agent from the syringe avoiding high negative pressure.

• If giving a bolus injection for left-heart contrast studies, a saline flush

(5mL) may be considered to push the agent into the central blood

stream if there is delayed contrast appearance. Lifting the arm is often

sufficient.

Contrast infusion

• Because of microspheres behaviour, continuous agitation of the

contrast is necessary for optimum contrast.

• Agitation can be performed manually by slowly rocking the pump to

and fro. A special infusion pump has been developed for SonoVue®.

A constant infusion of SonoVue® 0.8mL/min from the start is usually

satisfactory and need not be changed in the majority of patients.

• The pump is particularly useful in stress echocardiography; the infusion

can be stopped at any time and resumed when needed. Between

infusion periods, the contrast agent is gently agitated.

Right-heart contrast agents

• Patient preparation also requires insertion of an intravenous cannula,

usually into an antecubital vein.

• Need to be given as a bolus injection through a relatively large bore

cannula in a relatively proximal location.

• Need to be given as a rapid bolus to ensure complete opacification of

the right atrium. Blood from both the superior and inferior vena cavae

streams into the right atrium and it is possible with slow boluses for

the bubbles not to mix into the flow from the inferior vena cava and

therefore not reach the interatrial septum.

• Another way some people use if they are having difficulties with

opacification of the atrium near the interatrial septum is to give an

injection into the femoral vein so that the bubbles travel up the

inferior vena cava.

ADMINISTRATION OF CONTRAST AGENTS

569

Advantages of bolus injections

• Easy to perform.

• Wash-in period and wash-out is visible.

• Agent is quickly used with little stability problems.

• Allows the highest peak enhancement.

Disadvantages of bolus injections

• Contrast is short-lived.

• The contrast effect changes during study.

• Timing of injection of bolus can be difficult.

• Comparative contrast studies difficult.

Advantages of contrast infusion

• Prolongs the period of contrast enhancement.

• Provides a steady (constant) effect.

• Allows the dose of the agent to be optimized and used efficiently.

Disadvantages of contrast infusion

• More complex than bolus injections to perform.

• Titration of contrast takes time.

570

CHAPTER 9 Contrast echocardiography

Contrast safety

Left-heart contrast agents

The safety of ultrasound contrast agents has been assessed in cohorts of

several thousand patients. Side effects have been noted but they are usually

mild and transient. Most frequent side effects of SonoVue® in clinical trials

were: headache (2.1%), nausea (1.3%), chest pain (1.3%), taste perversion

(0.9%), hyperglycaemia (0.6%), injection site reaction 0.6%), paraesthesia

(0.6%), vasodilation

(0.6%), injection site pain

(0.5%). Serious adverse

events in particular allergic reactions are very rare

(0.01%) and less

frequent than for X-ray contrast agents.

• Allergic reactions: They may happen as acute sensitivity reactions (IgE

mediated type I), but Complement Activation Related Pseudo Allergy

(CARPA) seems to be more typical for the contrast agents with a

phospholipid membrane (SonoVue® and Luminity®). In comparison to

IgE mediated reactions, CARPA reactions need no prior exposure to

the agent, the reaction is milder or absent upon repeated exposures

and spontaneous resolution is possible. Although serious adverse

events are very rare, appropriate allergy and emergency equipment as

well as a physician with knowledge in emergency medicine should be

present or close by.

• Acute coronary disease: Only Optison® and Luminity® may be used in

acute coronary syndromes, since their contraindication on the use in

these conditions has been recently withdrawn by FDA, based on the

evidence of their favourable risk:benefit profile and safety. SonoVue®

may be used 7 days after acute coronary syndrome.

• Special considerations and precautions with use: mechanical

ventilation, clinically significant pulmonary disease (including diffuse

interstitial pulmonary fibrosis and severe chronic obstructive

pulmonary disease), adult respiratory distress syndrome, severe heart

failure (NYHA IV), endocarditis, acute myocardial infarction with

ongoing angina or unstable angina, hearts with prosthetic valves, acute

states of systemic inflammation or sepsis, known states of hyperactive

coagulation system, recurrent thromboembolism.

Right-heart contrast agents

Reports of serious side effects from the use of agitated saline injection are

rare. There have been a few case reports of agitated saline contrast caus-

ing ischaemic complications such as stroke or transient ischaemic attacks.

Available data is not sufficient to estimate the incidence of these events,

although such complications appear to be extremely rare.

CONTRAST SAFETY

571

Management of allergic reactions¹

• Recognize signs and symptoms of an allergic reaction: itching,

erythema, urticaria, wheeze, laryngeal obstruction, tachycardia,

hypotension.

• Ensure airway is secure and give 100% O2.

• If any signs of airway obstruction seek anaesthetic help to maintain

airway patency.

• If suspected anaphylaxis give IM adrenaline 0.5mg (i.e. 0.5mL of

1:1000). Repeat every 5min if needed as guided by blood pressure,

pulse, and respiratory function until better.

• Secure IV access

• Chlorpheniramine 10mg and hydrocortisone 200mg IV.

• IV normal saline titrated against blood pressure.

Ensure appropriate monitoring on ward: cardiac monitor, regular blood

pressure review.

Left-heart contrast agents in pregnant or lactating women

• No left-heart ultrasound contrast is approved for use in pregnant or

lactating women.

• In women of childbearing age the physician has to ask for confirmed

or possible pregnancy.

• Ultrasound contrast injections should be avoided unless there is no

alternative imaging method to answer the clinical question and the

clinical need for information is felt to be greater than any potential

risks.

Reference

1 Longmore M et al. (eds) (2010). Oxford Handbook of Clinical Medicine, 8th edn. Oxford: Oxford

University Press.

572

CHAPTER 9 Contrast echocardiography

Right-heart contrast study applications

Contrast study for atrial shunts and patent foramen ovale

Microbubble contrast studies can be used to identify atrial shunts and

confirm the presence of a patent foramen ovale (Fig. 9.7). There are 3

elements to a good contrast study for an atrial shunt:

A stable image

• Use apical 4-chamber view (or subcostal view) optimized so that all

4 chambers are seen. Try the view with the patient doing a Valsalva to

ensure you can keep all chambers in view.

Agitated saline injection

• Inject rapidly through a Venflon® inserted into an antecubital vein. It

must completely and rapidly opacify the right atrium.

A good Valsalva

• Shunting may be evident at rest so the first contrast injection should

be without Valsalva.

• If no bubbles appear in the left heart repeat the injection with a

Valsalva manoeuvre.

• The critical time of a Valsalva is when the patient relaxes. It is then

that right-sided pressures transiently elevate relative to the left and

contrast shunts.

• Get the patient to take a breath and bear down hard. Inject the

contrast and when it has filled the right atrium tell them to relax.

If there is a shunt a few bubbles will appear in the left atrium and left

ventricle within 5 beats of the patient relaxing. If bubbles appear later

this is more consistent with a pulmonary arteriovenous malformation.

• Set the system to capture 10-20 beats and start acquisition on

contrast injection. Look back through the loop for bubbles. Repeat

the study with more contrast until all three elements of the study are

perfect.

• The appearance of bubbles in the left heart within 5 cardiac cycles

following right chamber opacification and release of Valsalva suggests

an intracardiac shunt.

574

CHAPTER 9 Contrast echocardiography

Contrast study for pulmonary shunts

Intrapulmonary shunts are often the result of pulmonary arteriovenous

malformations. Intravenous agitated saline contrast can be used to aid the

diagnosis of intrapulmonary shunts.

• A stable image position and adequate agitated saline injection should

be used as described on b p.572.

• The appearance of bubbles in the left heart only after 5 cardiac cycles

suggests an intrapulmonary shunt.

Contrast study for Doppler enhancement

Intravenous injection of agitated saline and other contrast agents can

be used to enhance the tricuspid regurgitation signal (Fig. 9.8). The con-

trast enhancement of a weak TR velocity jet signal allows more accurate

estimation of right heart haemodynamics. Right-heart contrast agents may

also enhance the appearance of hepatic vein flow reversal.

• Acquire the TR jet CW signal by placing the CW cursor across the TR

jet as in the normal examination (see b p.162).

• Inject the agitated saline or left-heart contrast.

• The contrast is likely to generate a lot of noise on the spectral trace so

reduce the gain until the enhanced Doppler envelope is evident.

Diagnosis of persistent left superior vena cava

The diagnosis of a persistent left SVC is usually made incidentally fol-

lowing identification of a dilated coronary sinus or because there are

difficulties with pacemaker lead insertion from the left side. This is be-

cause a persistent left-sided SVC most frequently drains directly into the

coronary sinus.

A good view of the coronary sinus and its insertion into the right

atrium is required. This can often be best done on TOE or with TTE

using a modified apical 4-chamber view tilted down to cut through the

coronary sinus.

• Following injection of agitated saline into the left arm the contrast is

seen to appear in the coronary sinus before the right atrium.

• In the majority of patients a right (normal) SVC is then also present.

Therefore when agitated saline is injected into the right arm it is

seen to enter the right atrium before any appearing in the coronary

sinus. However, if the right SVC is absent then this injection will also

appear in the coronary sinus first.

576

CHAPTER 9 Contrast echocardiography

Imaging techniques for left ventricular

opacification

The durability of the contrast agent within the left ventricle is highly

dependent upon both the bubble composition and also the ultrasound

settings. Optimizing the ultrasound settings is vital to ensure good opacifi-

cation of the LV (Table 9.1).

Imaging presets and analysis

• When ultrasound contrast agents are used, contrast-specific imaging

modalities should be employed (Fig. 9.9) based on the use of harmonic

frequencies and low transmit power from the transducer.

• There are a range of manufacturer specific presets. The standard is a

real-time, low power mode. The low-power contrast-specific imaging

technology provides excellent ventricular opacification and often

simultaneous myocardial opacification.

• In systems without contrast-specific imaging modality use harmonic

imaging but with a mechanical index of <0.6.

Contrast specific imaging

• When exposed to ultrasound waves, the contrast bubbles resonate

and emit harmonic frequencies in addition to the frequency that

comes from the transducer, the fundamental frequency. The harmonic

frequencies are two times greater than the fundamental (second

harmonic), three times (third harmonic), and so on. With increasing

frequency the amplitude of the ultrasound waves decreases.

• Myocardial tissue shows the same response to ultrasound but only

with high transmit power (MI>1). Microbubbles will resonate at low

powers (MI=2).

• Thus, if the transducer is set to low power imaging the harmonic

signals from the contrast in the blood will be significantly stronger than

any signals from the myocardium and therefore excellent blood to

myocardial contrast is obtained.

Image settings to prevent microbubble destruction

The transmitted ultrasound frequency from the ultrasound machine can

destroy the microbubbles. Bubble destruction can be done purposefully

in some forms of imaging such as myocardial flash perfusion imaging but

usually stable micro-bubbles are needed to optimize image quality. To

increase the length of time microbubbles persist in the circulation there

are two imaging aspects that can be varied:

• Low mechanical index: The higher the mechanical index, the greater the

transmitted acoustic power and the higher the chance of microbubble

destruction. Using lower mechanical indexes will therefore also reduce

the destruction of micro-bubbles. However, this needs to be balanced

against the need for penetration to achieve adequate depth of imaging,

for which higher mechanical indexes can be used.

• Intermittent imaging: Continuous imaging with the transducer on the

chest wall will cause a gradual depletion of microbubbles. Therefore

intermittent imaging is recommended to increase microbubble durability.

578

CHAPTER 9 Contrast echocardiography

Left-heart contrast study applications

Contrast study for left ventricular opacification

European Association of Echocardiography indications for resting left ven-

tricular opacification contrast are as follows:

In patients with suboptimal images:

• To enable improved endocardial visualization and assessment of LV

structure and function when 2 or more contiguous segments are not

seen on non-contrast images.

• To have accurate and repeatable measurements of LV volumes,

and ejection fraction by 2D/3D echo (e.g. before CRT, follow-up

echocardiograms for assessment of cardiac toxicity) (Fig. 9.10).

• To increase the confidence of the interpreting physician in the LV

function, structure, and volume assessments.

• To confirm or exclude the echocardiographic diagnosis of the

following LV structural abnormalities, when non-enhanced images are

suboptimal for definitive diagnosis:

• Apical hypertrophic cardiomyopathy, LV non-compaction.

• Ventricular non-compaction.

• Apical thrombus (Fig. 9.11).

• Ventricular pseudoaneurysm.

Contrast study for Doppler enhancement

• Intravenous injection of left-heart contrast agents can be used to

enhance Doppler signals. The technique is as for right-heart agents

(see b p.574).

• As left-heart contrast agents pass from the right to the left heart,

they can be used to augment Doppler traces from the right heart

(e.g. tricuspid valve) and also the left heart.

• In the left heart, contrast can be used to enhance mitral Doppler

traces or pulmonary vein Doppler traces for the assessment of

diastolic dysfunction.

• Since only small amounts of contrast are needed for this indication,

Doppler enhancement can be achieved in the wash-out phase after

LV opacification. Usually the Doppler and/or power gain needs to be

reduced to achieve normal intensity spectra.

580

CHAPTER 9 Contrast echocardiography

Contrast study in dobutamine stress

echocardiography

Since image quality is crucial for reliable stress echocardiography, review

all baseline images prior to beginning the stress procedure. If endocar-

dial borders are not visible (or barely visible) in 2 or more myocardial

segments consider using an ultrasound contrast agent (Fig. 9.12).

Indications for use of contrast in stress echocardiography

• When 2 or more endocardial border contiguous segments of LV are

not well visualized.

• To obtain diagnostic assessment of segmental wall motion and

thickening at rest and stress.

• To increase the proportion of diagnostic studies.

• To increase reader confidence in interpretation.

Contraindications

• Known or suspected significant intracardiac shunts.

• Known hypersensitivity to the agent.

582

CHAPTER 9 Contrast echocardiography

Contrast study for myocardial

perfusion

The use of left-heart ultrasound contrast agents for the assessment of

myocardial perfusion has the potential to significantly improve myocardial

assessment during stress echocardiography. Myocardial contrast echocar-

diography is quick, easy to perform, and potentially a bedside technique

(as long as facilities for an infusion of contrast are available). Contrast

echocardiography supplements wall motion information with perfusion

judged from the appearance of contrast within the myocardium.

Principle

• Myocardial contrast echocardiography (perfusion imaging) describes

echocardiography with intravascular ultrasound contrast agents.

• This results in opacification of the cavities and the intramyocardial

blood vessels.

• The amount of myocardial opacification depends on the settings of the

ultrasound scanner, the density of the myocardial micro vessels (where

most of the myocardial blood is located), and the myocardial blood

flow.

• Differences in the intensity of myocardial opacification and in the

speed of filling the myocardium with contrast can be used to identify

areas of non-viability and/or ischaemia.

Indications

• At present most guidelines for echocardiographic assessment of

ischaemia and viability are based on assessment of LV wall motion

alone.

• Ultrasound contrast agents are approved for LV opacification

and endocardial definition. At present, assessment of myocardial

perfusion is not an approved indication for ultrasound contrast

agents.

• However, using state-of-the-art equipment myocardial opacification

often is inevitable when performing contrast echo for LV

opacification (Table 9.1).

• It is worth including these findings when assessing the patient for

myocardial viability and ischaemia as the perfusion data can confirm

sometimes questionable findings on LV wall motion.

• Protocols that exclusively make the diagnosis from perfusion images

may be an option in the future.

CONTRAST STUDY FOR MYOCARDIAL PERFUSION

583

Table 9.1 Common pitfalls seen in myocardial contrast

echocardiography and their solutions

Pitfall of myocardial contrast

Solution

echocardiography

Insufficient contrast dosage and/or

Increase contrast dose and/or

setting causing inhomogeneous

correct setting

opacification and swirling

Nearfield destruction artefacts in the

Stepwise reduce transmit power (MI)

apical parts of the left ventricle setting

in 0.1 step and/or change focus to

causing inhomogeneous opacification and

farfield

swirling

Very strong signals in the nearfield and

Increase transmit power or just wait

poor LV contrast in the farfield

several beats, for subsequent

particularly in the basal part of the

injections use a small dosage or a

LV segments

slower bolus

Rib shadows can be found in all segments:

Try modified view

look for the typical band of low

echogenicity

584

CHAPTER 9 Contrast echocardiography

How to set imaging parameters

A balance between having sufficient power of the ultrasound and an

adequate signal-to-noise ratio without significant microbubble destruction

is important to achieving adequate perfusion imaging. Both high power and

low power (MI <0.2) have been used.

• High power: High power provides good signal-to-noise ratio although

there is destruction of microbubbles and so assessment of myocardial

perfusion cannot be performed in real time nor can it be performed

simultaneously with assessment of wall motion.

• Low power: Low power imaging reduces microbubble destruction

allowing simultaneous assessment of perfusion and wall motion

although has a lower sensitivity for the detection of microbubbles.

How to assess myocardial perfusion

The myocardial contrast distribution can be visually assessed to give

the operator an impression of overall myocardial perfusion (Fig. 9.13).

Continuous infusion of contrast is used and the microbubbles are

destroyed by a high burst of ultrasound at a high mechanical index causing

a ‘flash’. Following this the replenishment of the contrast agent within the

myocardium and its distribution can be visually assessed (Fig. 9.13).

• The presence of an intact coronary microvasculature and normal

myocardial blood flow allows an even replenishment of contrast within

the myocardium.

• If there is diminished epicardial flow (e.g. following myocardial

infarction) the speed and amount of contrast replenishment will be

Training and accreditation

Basic and stress echocardiography training including BLS/ALS is needed.

As long as there are no approved procedures for accreditation in contrast

echocardiography the following approach appears to be reasonable:

• Introduction by a physician with experience in contrast

echocardiography (>50 studies/year).

• Participation in a course on contrast echocardiography in order to

learn the performance, interpretation, pitfalls, and adverse effects in

contrast echocardiography.

• Perform at least 20 contrast echoes under guidance or supervision.

• Experience with contrast agent for left ventricular opacification in at

least 50 cases is a prerequisite for moving on to assess perfusion and

function with contrast agents.

588

CHAPTER 10 Stress echocardiography

Introduction

Stress echocardiography has become a valuable method for cardiovascular

stress testing. It plays a crucial role in the initial detection of coronary

artery disease, in determining prognosis, and in therapeutic decision-

making. The major use of stress echocardiography is to assess myocar-

dial ischaemia or viability in patients with coronary artery disease. Stress

echocardiography can also be applied to evaluation of valvular disease and

cardiomyopathies.

Stress echocardiography or other non-invasive

imaging tests?

Non-invasive imaging techniques have greatly improved the evalu-

ation of patients with known or suspected coronary artery disease.

Stress echocardiography and myocardial scintigraphy are widely avail-

able and provide similar diagnostic accuracy along with an incremental

value over clinical risk factors for detection of coronary artery disease.

Cardiovascular magnetic resonance (CMR) is the most recent addition

to the functional cardiac imaging armamentarium. It offers a comprehen-

sive assessment of myocardial ischaemia which may include wall-motion

analysis at rest and during dobutamine stress, or rest and stress first-

pass myocardial perfusion during vasodilatory stress. Myocardial viabil-

ity is evaluated with either the late gadolinium enhancement technique

(infarct imaging) or the low-dose dobutamine test. Positron emission

tomography has high diagnostic performance to detect ischaemia and

viability, but continues to have limited clinical use because it is not widely

available. Cardiac computed tomography allows coronary calcium scan-

ning along with non-invasive anatomic assessment of the coronary tree,

but no functional information on ischaemia/hibernation. Therefore, it

should be combined with a functional test (ideally stress echocardiogra-

phy or CMR, and not myocardial scintigraphy which also involves radia-

tion), to provide a complete assessment of the physiological significance

of stenotic lesions in coronary arteries.

There are clinical situations where myocardial scintigraphy is relatively

contraindicated (left bundle branch block, bifascicular block, and ven-

tricular paced rhythms). In these situations dynamic exercise leads to

perfusion abnormalities of the septum and adjacent walls in the absence

of obstructive coronary disease. If there is local expertise, stress echocar-

diography is an option. On the other hand, in patients with known exten-

sive coronary artery disease and regional wall abnormalities at rest, the

diagnostic accuracy of stress echocardiography is somewhat reduced. If

available, CMR with adenosine first-pass perfusion and late gadolinium

enhancement is an attractive option for those patients. No single imag-

ing modality has been proven to be superior overall. Available tests all

have advantages and drawbacks, and none can be considered suitable for

all patients. The choice of the imaging method should be based on the

clinical history and also on local expertise and availability.

INTRODUCTION

589

Pre-test probability

In patients referred for stress echocardiography the likelihood of having

coronary artery disease can usually be estimated from their symptoms

and history. This pre-test probability is useful because the gain by per-

forming a stress test depends on the pre-test probability (Table 10.1).

Based on the accuracy of stress echocardiography to detect coronary

artery disease it is also possible to calculate the probability of coronary

artery disease with a negative or positive result of stress echocardiogra-

phy (post-test probability).

If there is a high pre-test probability (e.g. typical angina and risk factors) the

risk of a cardiac event remains high even if there is a negative test. In patients

with a low pre-test probability (e.g. young patients with atypical chest pain)

a positive test does not predict poor prognosis. Therefore, when used for

diagnosis, stress echocardiography (like nuclear perfusion imaging) is ideal

for patients with intermediate pre-test probability (e.g. women with atypical

chest pain and some risk factors). In this group of patients a negative test

predicts a low risk of further cardiac events, whereas a positive test indicates

a high risk and warrants further invasive diagnostics.

Although stress echocardiography in patients with high pre-test prob-

ability is of limited diagnostic value, it is still of clinical value. In patients

with known coronary artery disease stress echocardiography can help to

define the location and extent of ischaemia.

Table 10.1 Combined Diamond-Forrester and CASS data of pre-test

likelihood of coronary artery disease in symptomatic patients. (Modified

from Committee on the Management of Patients with chronic stable

angina. ACC/AHA 2002 guideline update for the management of

patients with chronic stable angina. J Am Coll Cardiol 2003; 41(1):159-68.)

Age

Atypical angina

Typical angina

Men Women

30-39

40-49

50-59

60-69

Values represents % with coronary artery disease on angiography

>70%

30-70%

<30%

590

CHAPTER 10 Stress echocardiography

Indications

The main indication for stress echocardiography is the assessment of

coronary artery disease patients (Fig. 10.1). ECG stress testing is the most

frequently used initial stress test to evaluate patients with suspected coro-

nary artery disease. Stress echocardiography is used in addition to stress

ECG or as the initial diagnostic tool. However, stress echocardiography

has been applied to several other pathologies. The key indications are to

aid management of patients with:

Suspected coronary artery disease

• As part of an investigational strategy for the diagnosis of patients in

whom stress ECG was inconclusive.

• For people for whom treadmill exercise is difficult or impossible

because of poor mobility or inability to perform dynamic exercise.

• For people for whom stress ECG poses particular problems of poor

sensitivity or difficulties in interpretation, including women, patients

with cardiac conduction defects (for instance, left bundle branch block

and resting ST segment abnormalities), and diabetes

• For people with a lower likelihood of coronary artery disease and

future cardiac events. Likelihood of coronary artery disease depends

on clinical assessment of risk factors including age, gender, ethnic

group, family history, associated comorbidities, clinical presentation,

physical examination, and results from other investigations (e.g. blood

cholesterol levels or resting ECG).

Known coronary artery disease

• To determine the likelihood of future coronary events, for

instance after myocardial infarction or risk assessment for proposed

non-cardiac surgery.

• To assess myocardial viability and hibernation, particularly with

reference to planned myocardial revascularization.

• To guide strategies of myocardial revascularization by determining the

haemodynamic significance of known coronary lesions.

• To assess the adequacy of percutaneous and surgical revascularization.

Valvular heart disease

• Aortic stenosis with a low gradient and poor left ventricular systolic

function (see Chapter 3).

• Aortic stenosis with a high gradient in asymptomatic patients.

• Mitral stenosis with discrepancy between haemodynamic and clinical

findings (e.g. dyspnoea despite low gradient at rest, asymptomatic

patient with high-grade stenosis).

• Mitral regurgitation (organic, severe) in asymptomatic patients.

• To establish evidence of inducible ischaemic mitral regurgitation.

• To evaluate aortic regurgitation (severe) in asymptomatic patients.

Hypertrophic cardiomyopathy or subaortic muscular

obstruction

• Assessment for dynamic gradient.

592

CHAPTER 10 Stress echocardiography

Contraindications

Absolute contraindications for all stress modalities

• Non-ST-segment elevation acute coronary syndrome. Once stabilized,

exercise stress can be considered 24-72 hours after chest pain, in

low- or intermediate-risk patients. High-dose dobutamine should not

be performed within the first week after a myocardial infarction.

• ST-segment elevation myocardial infarction within the previous 4 days.

• Left ventricular failure with symptoms at rest.

• Recent history of life-threatening arrhythmias.

• Severe dynamic or fixed LVOT obstruction (aortic stenosis and

obstructive hypertrophic cardiomyopathy).

• Severe systemic hypertension (systolic blood pressure >220mmHg

and/or diastolic blood pressure >120mmHg).

• Recent pulmonary embolism or infarction.

• Thrombophlebitis or active deep vein thrombosis.

• Known hypokalaemia (particularly for dobutamine stress).

• Active endocarditis, myocarditis, or pericarditis.

• Left main coronary artery stenosis that is likely to be

haemodynamically significant.

Absolute contraindications for vasodilator stress

• Suspected or known severe bronchospasm.

• 2nd- and 3rd-degree atrioventricular block in the absence of a

functioning pacemaker.

• Sick sinus syndrome in the absence of a functioning pacemaker.

• Hypotension (systolic blood pressure <90mmHg).

• Caffeine intake, xanthines, or dipyridamole use in the last 24 hours.

Relative contraindications to vasodilator stress

• Bradycardia of <40bpm. Initial dynamic exercise normally increases the

rate sufficiently to start the infusion.

• Recent cerebral ischaemia or infarction.

Contraindications to contrast imaging

• Known allergy to any of the constituents of contrast agents.

594

CHAPTER 10 Stress echocardiography

Detection of ischaemia

Principle

The rationale for the diagnosis of myocardial ischaemia with stress

echocardiography is a relative reduction in myocardial blood flow on

stress sufficient to cause a decrease in myocardial contraction. The ischae-

mic changes in left ventricle wall motion appear earlier than ECG changes

and angina (the ischaemic cascade, Fig. 10.2). During stress, in a normal

subject, coronary and myocardial blood flow increases 3-4-fold to comply

with the increased oxygen demand of the myocardium. This can occur

because myocardial arteriolar resistance reduces. If there is a significant

stenosis of an epicardial coronary artery the resistance of the arteriolar

vessels is already reduced at rest. This is known as auto-regulation and

allows preservation of coronary blood flow at rest, and at low levels of

stress, in the territory supplied by the stenosed artery. Therefore, at rest

severe occlusions do not result in wall motion abnormalities. However,

with stress and increased oxygen demand the blood flow cannot be fur-

ther increased and the corresponding myocardial segment cannot con-

tract as well as myocardial segments supplied by patent arteries. The more

severe the epicardial stenosis the smaller the possible increase in coronary

blood flow and the earlier wall motion abnormalities occur.

Limitations

• Usually stenosis >50% results in wall motion abnormalities on stress.

However, less severe stenosis in particular with long segments or

vascular remodelling can also cause ab-normalities.

• There has to be a significant increase in oxygen demand to disclose

regional wall motion abnormalities—in particular for moderate

stenoses. This is only possible by reaching or exceeding target heart

rates as in exercise ECG stress testing.

• Even severe stenosis may be missed if there is a well-developed

collateral circulation.

• Worsening of wall motion or an inappropriate loss of contractility in

comparison to other myocardial segments is the hallmark of stress

echocardiography. However, this may be difficult to visualize if resting

function is already reduced.

• Abnormal microvascular function, e.g. in arterial hypertension

or diabetes, may reduce the auto-regulation and cause abnormal

responses to stress. However, the changes are usually diffuse and not

segmental as observed in coronary artery disease.

596

CHAPTER 10 Stress echocardiography

Viability assessment

• Viability studies based on left ventricular wall motion are performed

when akinetic (or severely hypokinetic) segments are found and

there is a question as to whether the patient will benefit from

revascularization. If segments are reported as viable this implies the

myocardial function is still preserved even though their blood supply

is limited (Fig. 10.3).

• The rationale for the diagnosis of myocardial viability with stress

echocardiography is to demonstrate that the akinetic (or severely

hypokinetic) segments improve contractility when exposed to low

doses of dobutamine. This ability to increase contractility is referred

to as a contractile reserve.

• If there is a haemodynamically significant stenosis or an occlusion of

the supplying artery, higher dosages of dobutamine may then result in

ischaemia and the contractility decreases. This improvement and then

deterioration is referred to as a biphasic response.

Limitations

• Dobutamine increases oxygen demand and at higher doses induces

ischaemia in hibernating myocardium (biphasic response). This usually

requires doses exceeding 20microgram/kg/min. However, very severe

stenoses may cause ischaemia at the lowest doses of dobutamine and

no improvement of contractility may be seen.

• Contractility depends on preservation of the inner layers of the

myocardium. Therefore the lack of contractile reserve does not mean

there is no viable myocardium in the outer layers. Although major

recovery of function after revascularization appears to depend on

preserved contractility, segments with irreversibly damaged inner

layers but preserved outer myocardial layers still may benefit from

improved blood flow and remodelling.

• It may be difficult to differentiate passive movement (tethering, i.e.

being pulled with a normally moving segment) of a myocardial segment

from active movement due to contraction. Image processing analysis

tools, such as strain imaging and tissue tracking, may be useful to

differentiate but there is limited experience.

• Viability assessment using stress echocardiography relies on good

image quality. Contrast echocardiography is usually needed to improve

border delineation.

VIABILITY ASSESSMENT

597

DOBUTAMINE STRESS

REST

LOW DOSE

HIGH DOSE

SYSTOLE

NORMAL

*ISCHAEMIA

HIBERNATION

- biphasic

viable

INTRAMURAL SCAR

- viable

SCAR

non-viable

not performed

WALL THICKENING

Fig. 10.3 Changes in wall thickening with dobutamine stress. *Decline in wall thick-

ening with ischaemia can be variable in degree and timing.

Causes of akinetic left ventricle segments

Scar (non-viable)

• Irreversible loss of myocardium.

• Often reduced diastolic wall thickness <0.6cm.

Stunning (viable)

• Transiently reduced contractility after ischaemia.

• Usually spontaneous recovery (e.g. transient coronary occlusion in

infarction with early recanalization, or post stress in severe stenosis).

• Stunning usually diagnosed by follow-up studies that demonstrate

recovery in function.

• If complete occlusion during infarction this can take 4-6 weeks.

Hibernation (viable)

• Permanently reduced contractility.

• Permanent coronary occlusion or high-grade stenosis with

insufficient collateral blood flow ‘too little to live, too much to die’.

• Transient recovery with low-dose dobutamine.

• Worsening with high dose ‘biphasic response’.

Intramural scar (viable)

• Scar in wall but with no significant stenosis in supplying artery and

remaining viable myocardium in wall.

598

CHAPTER 10 Stress echocardiography

Perfusion assessment

Principle

• Normal viable and non-ischaemic myocardium can be recognized

by observing the pattern of myocardial contrast enhancement

(see Chapter 9 and Fig. 10.4).

• Usually with normal perfusion the microvessels fill with contrast and

there is homogeneous opacification and prompt refill of contrast

following microbubble destruction.

• After myocardial infarction, scar tissue replaces the myocytes and

the density of intramyocardial vessels decreases. Similarly, in acute

myocardial infarction without reperfusion, myocardial blood flow is

absent in the necrotic area. Therefore the myocardial opacification

decreases and ‘dark’ or ‘black’ areas are seen within the myocardium,

usually in the subendocardial region.

• Typically infarct and scar tissue do not opacify because the amount

of contrast within the few vessels remaining is not enough to cause

an ultrasound signal. Therefore for viability assessment with contrast

only a resting study is necessary. Nevertheless the echocardiographic

method of choice for viability assessment is still low-dose dobutamine

stress and perfusion imaging is only considered when contrast has

been used for LV opacification or when dobutamine is contraindicated.

• If an area of myocardium starts to become ischaemic during a stress

study, again the perfusion with microbubbles decreases and the refill

of contrast reduces. Therefore the area becomes dark.

• Myocardial ischaemia is present when 2 or more myocardial segments

show normal opacification at rest and a perfusion defect during stress.

• Assessment for inducible ischaemia can be performed with all

approved stress protocols, but appear to be most suitable for

vasodilator protocols.

• In the ischaemic cascade, stress-induced myocardial perfusion defects

tend to precede wall motion abnormalities and as a result subtle wall

motion abnormalities can often be identified when a perfusion defect

has also become evident.

• It is important to remember that myocardial perfusion defects may be

transient and are often better seen during the replenishment after the

flash.

Limitations of perfusion assessment

• Scar tissue sometimes can cause a very echogenic tissue signal. This

makes it very difficult to assess changes in myocardial opacification

after contrast injection.

• A perfusion defect at rest is found in an akinetic segment, if not

consider an artefact.

600

CHAPTER 10 Stress echocardiography

Preoperative assessment for

non-cardiac surgery

• In patients undergoing major vascular surgery a dobutamine stress

echocardiogram allows determination of the perioperative risk for

cardiovascular complications. This is particularly useful if patients have

3 or more of the characteristics: age >70 years; current angina; prior

myocardial infarction; congestive heart failure; prior cerebrovascular

event; diabetes mellitus; or renal failure.

• The main method to protect patients with known coronary artery

disease perioperatively is to prescribe effective beta-blockade.

The risk of perioperative cardiac complications has been assessed

in clinical trials and is related to the number of wall segments that

become ischaemic on dobutamine stress echocardiography.

• Patients without new wall motion abnormalities have a low risk (<5%).

Patients with 1-4 segments showing new wall motion abnormalities

have a slightly higher perioperative risk but can be protected with

beta-blockers.

• If >4 segments exhibit new wall motion abnormalities during stress,

there is a high risk (>30%) of cardiac complications perioperatively.

This risk cannot be reduced by beta-blockers and there is therefore a

potential theoretical benefit from revascularization (although currently

unproven to reduce risk).

• The most recent guidelines (Fig. 10.5) were published in 20091. These

take into account the urgency of the surgery, the cardiac risk of the

surgery, the patient’s functional capacity, as well as cardiac risk factors.

• In patients with t3 cardiac risk factors then non-invasive testing can

be considered. If this shows dmoderate stress-induced ischaemia

and the patient is stable then the planned surgery can go ahead. If

non-invasive stress testing shows extensive ischaemia then each case

should be considered individually considering the potential benefit of

the proposed surgical procedure with the predicted outcome and the

effect of medical therapy and/or coronary revascularization.

Reference

1 Task Force for Preoperative Cardiac Risk Assessment and Perioperative Cardiac Management

in Non-cardiac Surgery; et al. Guidelines for pre-operative cardiac risk assessment and

perioperative cardiac management in non-cardiac surgery. Eur Heart J 2009; 30:2769–812.

PREOPERATIVE ASSESSMENT FOR NON-CARDIAC SURGERY

601

Cardiac Risk Factors

(angina, previous MI, heart

failure, previous CVA/TIA,

renal dysfunction, diabetes

mellitus requiring insulin)

>3 cardiac risk factors

Yes

Consider non invasive

testing prior to surgical

Continue with surgery

procedure

If extensive ischaemia

If non invasive testing

present on non invasive

shows ≤ moderate stress-

stress testing then each

induced ischaemia and the

case should be considered

patient is stable then the

individually considering the

planned surgery can go

potential benefit of surgery

ahead

against risks

Fig. 10.5 Flow chart showing preoperative assessment for non-cardiac surgery.

Task Force for Preoperative Cardiac Risk Assessment and Perioperative Cardiac Management in

Non-cardiac Surgery; et al. Guidelines for pre-operative cardiac risk assessment and perioperative

cardiac management in non-cardiac surgery. Eur Heart J 2009; 30:2769–812.

602

CHAPTER 10 Stress echocardiography

Equipment and personnel

Equipment

Because analysis of wall motion abnormalities is difficult and not reliable

in the presence of poor quality images, every effort has to be made to

optimize visualization of the endocardial border and the myocardium.

• The scanner should provide tissue harmonic imaging and a contrast-

specific imaging modality in order to be applicable in the majority of

patients.

• Use of digital frame grabbers and split or ‘quad-screen’ displays allow

side-by-side comparison of rest and stress images using the same

echocardiographic views and is the current standard for performing

stress echocardiograms.

• Tissue Doppler imaging is optional but may add clinical information

(e.g. detection of post-systolic shortening).

• 3D imaging, which is becoming increasingly available, offers the ability

to eliminate apical foreshortening and shorten the time needed for

acquisition of stress images.

Personnel and experience

• Two people are required to record and monitor stress

echocardiography—one of them should have substantial experience in

the evaluation of patients with ischaemic heart disease and in analysis

of wall motion/thickening abnormalities.

• Recordings should be performed by a skilled echocardiographer

(technician or physician).

• If a physician is not participating in the study, one should be available in

the immediate locality in case of acute problems. One of the personnel

present should be qualified in advanced life support.

• Recording and interpretation of stress echocardiograms requires

extensive experience in echocardiography and should be performed

only by technicians and physicians with specific training in the

technique. Most recommendations suggest physicians have performed

and interpreted a minimum of 100 studies under supervision

before they can perform stress echocardiography independently.

Supervised over-reading of at least 100 stress echocardiograms is

required to attain the minimum level of competence for independent

interpretation.

Drugs

• Depending on the stress protocol chosen the appropriate drugs

(dobutamine, adenosine, dipyridamole, atropine) and agents to reverse

their effects should be prepared (aminophylline if dipyridamole used,

beta-blockers).

• Standard resuscitation drugs and equipment will need to be available in

the room.

604

CHAPTER 10 Stress echocardiography

Patient preparation

Patients should be provided with information or have a detailed verbal

explanation. Informed consent is usually considered appropriate especially

for pharmacological stress or with the use of contrast agents.

Safety

A large international study of stress echocardiography reported on

85,997 patients undergoing stress echocardiography.1 The incidence of

life-threatening adverse events in those undergoing stress with exercise

was 1:6574, dobutamine 1:557, and dipyridamole 1:1294. There were

6 deaths (1:14333) related to the procedure (5 with dobutamine, and

1 with dipyridamole). These were mainly due to ventricular arrhythmias.

It was pointed out that the subgroup of patients receiving dobutamine

may have been at higher risk because of viability studies in those with

established coronary disease.

Reference

1 Varga A et al. Safety of Stress Echocardiography (from the International Stress Echo

Complication Registry). Am J Cardiol 2006; 98:541–3.

PATIENT PREPARATION

605

Example information sheet

You have been asked to attend for stress echocardiography. A stress

echocardiogram is an ultrasound scan of your heart, which is performed

after increasing your heart rate. A stress echocardiogram provides in-

formation about the performance of your heart at stress and helps your

doctors to identify symptoms you may have on exertion.

Before the procedure?

Please continue to take all your medications as usual except for your

beta-blocker which should not be taken on the morning of the test.

You will be seen by the doctor who will take a medical history and after

explaining the procedure will ask you to sign a consent form. If you have

any concerns, please do not hesitate to ask, as we would like you to be

as relaxed as possible and are happy to answer questions.

What happens during the procedure?

The doctor will insert a small tube into your arm (cannula) to infuse the

drug (dobutamine), which increases the heart rate. A blood pressure cuff

will be placed on your arm. You will be asked to lie on your left side and

the ultrasound scan will be performed. Dobutamine will be given via the

cannula, which will gradually increase the heart rate. In addition ultra-

sound contrast agents may be given to improve image quality. There will

be a doctor present and also a technician. The procedure takes 20-30min

to examine all areas carefully. When the examination is finished the dob-

utamine is stopped and the heart rate will come down quickly.

Benefits?

The benefits from stress echocardiography are that it can: Define the

nature of cardiac symptoms; Point out the status of the cardiovascular

system; Decide which further therapeutic and diagnostic procedures you

have to undergo following the information derived from this examination.

Risks?

Usually the investigation is tolerated well, some patients could have

some mild symptoms during the test (mostly palpitations, tremor, light

headed sensation). Serious risks are very rare less than 0.3% (1 in every

330 patients) and include heart rhythm problems, myocardial infarction

and low blood pressure. Your doctor would not recommend that you

have a stress echocardiogram unless she/he felt that the benefits of the

procedure outweighed these small risks.

After the procedure?

After the procedure you will be asked to stay for another 30min. This

is the time needed to completely clear the infused drugs. You will be

offered refreshments. The doctor will return and discuss the results of

your procedure. Any relevant advice and literature will then be given.

Your cannula will be removed and you may go home with your relative/

friend. A letter with the results of your procedure will be sent to your

GP and any referring doctor.

606

CHAPTER 10 Stress echocardiography

Performing the study

General

The image acquisition is structured to make it easy to identify changes

from baseline in wall motion and thickening of the left ventricle. The fun-

damental requirement is high-quality 2D echocardiographic recordings

with good endocardial border definition in all segments. These basic im-

ages need to be acquired confidently and quickly during stress. Additional

data can include tissue Doppler profiles (global and regional parameters

of function) and direct assessment of myocardial perfusion by myocardial

contrast enhancement (depending on local licences).

Views

Multiple views are required to ensure all left ventricular segments are

monitored and all 3 major coronary distributions are assessed. The key

4 views are: apical 4- and 2-chamber, parasternal short and long axis (or

apical long axis) (Fig. 10.6). Subcostal or additional short-axis views can be

substituted when necessary or when more appropriate for visualization of

specific anatomy.

Set-up

• Spend time ensuring good patient position (they will be in this position

throughout the stress). A clear, stable ECG recording is required.

• Study all 4 views and spend time optimizing the images.

• Machine settings: select harmonic imaging and adjust focus zone.

Ideally, frame rate should be >25 frames/s (if heart rate >140 then

frame rates >30 frames/s may be better).

• Probe position: be very careful not to foreshorten apical views

(Fig. 10.7). The patient may need to do held inspiration or

expiration for clear, stable, unforeshortened images.

• Contrast: decide whether there is good endocardial border

definition in each view and whether images can be acquired

confidently and smoothly during the stress in each window. If 2 or

more segments are not seen or the images are difficult use contrast.

PERFORMING THE STUDY

607

FOUR KEY VIEWS

PARASTERNAL LONG AXIS

PARASTERNAL SHORT AXIS

APICAL FOUR CHAMBER

APICAL TWO CHAMBER

Fig. 10.6 There are 4 key views. The parasternal long axis and apical 3-chamber

provide very similar information. See W Video 10.1, W Video 10.2, W Video 10.3,

W Video 10.4, W Video 10.5, W Video 10.6, W Video 10.7, W Video 10.8.

RIB

TRUE APICAL POSITION

FORESHORTENED VENTRICLE

PROBE ROTATION

Fig. 10.7 It is vital that all apical views are not foreshortened to avoid missing apical

wall motion abnormalities. If the probe is not on the true apex then even though

the apex may be included in the initial plane probe rotation for the next view will

create a foreshortened image.

608

CHAPTER 10 Stress echocardiography

Image acquisition

• Record a set of baseline images (use a stress protocol preset if

available). Use a standard acquisition order, e.g. parasternal long

axis, parasternal short axis, apical 4-chamber and apical 2-chamber

(alternatively the apical views can be recorded first).

• Start the stress (e.g. pharmacological/physical).

• At the preset time-points (depending on stress and clinical response)

record a complete set of images. Some machines have a ‘compare’

mode to ensure your images are in exactly the same position.

• Look for changes in wall motion and thickening during image

acquisition so that you interpret the test as you go along.

• Once all the images are acquired, review them off-line, ideally with a

second experienced reviewer, to create the final report.

3D stress applications

3D stress echocardiography

• Real-time 3D stress echocardiography allows the acquisition of a full

volume image of the left ventricle. This has several advantages: all

segments are imaged quickly and during the same time interval and

accurate comparisons can be made.

• The cropping of 3D volumes allows planes to be chosen which are

‘on axis’ which is sometimes difficult to achieve exactly with 2D

stress echocardiography.

• The reduced temporal resolution of stress echocardiography means

that LV contrast agents are invariably used.

• The presence of stitching artefacts can also hinder image analysis,

particularly if there is quick variability in the heart rate.

• However, acquisition of 3D datasets allows for other potential

assement of ischaemia such as changes in strain (Fig. 10.8).

• Whilst the advantages of 3D stress echocardiography are clear, the

reduced image quality and problems with stitching has limited its

uptake by cardiology departments.

iRotate

• This mode, offered by Phillips allows the 2D image to be rotated to

a different plane whilst maintaining the probe in the same position.

• This mode can be of use during stress echocardiography where

for instance following acquisition of the apical 4-chamber view the

ultrasound waves are transmitted in a different direction to obtain

a 2-chamber apical view and then a 3-chamber apical view without

moving the ultrasound probe.

610

CHAPTER 10 Stress echocardiography

Monitoring and termination criteria

Monitoring

As with other forms of stress testing, standard ECG and blood pressure

monitoring should be performed. This may provide diagnostic and prog-

nostic information during exercise studies. With pharmacological stress

ECG monitoring has limited diagnostic value but is needed to trigger loop

recording and monitor for arrhythmias. However, if a 12-lead ECG is not

performed during pharmacological stress, a 12-lead ECG recorder should

be readily available in case of problems.

Termination criteria

Treadmill exercise echocardiography should be terminated at traditional

endpoints:

• Attainment of target heart rates.

• Cardiovascular symptoms.

• Significant ECG changes or arrhythmias.

Bicycle exercise and pharmacological stress provide additional echocar-

diographic endpoints because they allow online, continuous visualization

of wall motion and thickening. Stress echocardiography with online moni-

toring should be terminated at:

• Traditional endpoints (previously listed).

• The development of wall motion abnormalities corresponding to 2 or

more coronary territories.

• Wall motion abnormalities associated with ventricular dilation and/or

global reduction of systolic function.

612

CHAPTER 10 Stress echocardiography

Exercise stress protocols

Exercise is the most physiological stressor for assessment of myocardial

ischaemia in patients able to exercise.

Stress protocol

• The protocols are the same as for exercise stress ECG testing.

• A Bruce treadmill protocol with 3-min stages of graded increases

in speed and gradient, or an ergometer with 3-min stages of graded

cycling resistance at a fixed cycling rate (Fig. 10.9).

• Treadmill exercise should be terminated at traditional endpoints such

as attainment of target heart rates, cardiovascular symptoms, and/or

significant ECG changes suggestive of ischaemia.

• Supine and upright bicycle exercise appear to have equivalent degrees

of accuracy. Supine bicycle ergometry on a special bed, which can be

rotated, provides additional echocardiographic endpoints because it

allows continuous visualization of wall motion at incremental levels of

stress, including peak exercise. Bicycle exercise should be terminated

at traditional endpoints and, if a supine bicycle is used, when wall

motion abnormalities develop that correspond with 2 or more

coronary territories, or wall motion abnormalities associated with

ventricular dilation and/or global reduction of systolic function.

Image acquisition

Imaging should be performed at:

• Baseline.

• Post treadmill exercise (because ischaemia-induced wall motion

abnormalities may resolve quickly, post-exercise imaging should be

accomplished within 60-90sec of termination of exercise). If the

patient is asymptomatic and there are no ECG changes then extending

the exercise up to 100% of target heart rate provides more time

post-exercise to acquire images.

• If supine bicycle ergometry is used imaging should also be performed

during exercise and an intermediate stage can be recorded.

Exercise or dobutamine?

For the diagnosis of myocardial ischaemia, there appears to be no dif-

ference in the accuracy and prognostic information obtained with dob-

utamine compared to exercise stress. It is possible that for milder forms

of coronary artery disease, treadmill may be advantageous. Exercise

stress echocardiography presents a challenge to obtain good quality

images. For patients unable to exercise, dobutamine is indicated. An

advantage of dobutamine is that it has a rapid onset and cessation of

action, and its effects can be reversed by beta-blocker administration. If

there is a contraindication to dobutamine then dipyridamole, adenosine

or pacing may be used. For risk assessment prior to non-cardiac sur-

gery the accuracy of dobutamine stress echocardiography is proven. For

assessment of myocardial viability use of low- and high-dose dobutamine

seems to be the best stress method for echocardiography.

614

CHAPTER 10 Stress echocardiography

Dobutamine stress for ischaemia

Myocardial ischaemia is assessed by graded dobutamine infusion. This increases

myocardial oxygen demand in a fashion analogous to staged exercise.

Contractility, heart rate, and systolic blood pressure are all increased.

Dobutamine infusion

• Start the infusion at 5 or 10microgram/kg/min dobutamine.

• At 3-min intervals increase the infusion to 20, 30, and then 40microgram/

kg/min.

• If the rise in heart rate is minimal by 30microgram/kg/min dobutamine

then consider using atropine (Fig. 10.10). Check for contraindications

to atropine, in particular glaucoma, before administration.

• Atropine should be used at the minimum effective dose. Administer

0.3mg doses at 60sec intervals until the desired heart rate response is

seen. Maximum dose should be 1.2mg. The effect on accuracy is not

fully established but appears beneficial.

Dobutamine stress and beta-blockers

In patients with ongoing beta-blocker treatment a reduced sensitivity

for reversible ischaemia has been found. This is seen even if target heart

rate is reached with additional atropine injections due to the negative

inotropic effect of beta-blockers. Therefore, it is recommended to stop

beta-blockers ideally 48 hours prior to the test to increase sensitivity

(avoid false negatives). However, if not possible, patients can still be

accepted for exercise or dobutamine stress with atropine accepting that

sensitivity is lower.

Image acquisition

See W Video 10.9, W Video 10.10, and W Video 10.11 for examples of wall motion

abnormalities. Images should be recorded at:

• Baseline.

• Intermediate stage (70% of the age-predicted heart rate).

• Peak stress (>85% of the age-predicted heart rate).

• Recovery.

The minimal images are baseline and peak. More than 4 stages can be

recorded as felt clinically needed.

Termination of test

Diagnostic endpoints of stress echocardiographic testing are: maximum

dose (for pharmacological) or maximum workload (for exercise testing):

achievement of target heart rate; obvious echocardiographic positiv-

ity (with akinesis of t2LV segments); severe chest pain; or obvious ECG

positivity

(with >2mV ST-segment shift). Submaximal non-diagnostic

endpoints of stress echo testing are non-tolerable symptoms or limiting

asymptomatic side effects such as hypertension, with systolic blood pres-

sure >220mmHg or diastolic blood pressure >120mmHg, symptomatic

hypotension, with >40mmHg drop in blood pressure; supraventricular

arrhythmias, such as supraventricular tachycardia or atrial fibrillation;

and complex ventricular arrhythmias, such as ventricular tachycardia or

frequent, polymorphic premature ventricular beats.

616

CHAPTER 10 Stress echocardiography

Dobutamine stress for viability

The basis for the diagnosis of myocardial viability is contraction of the

myocardium either spontaneously or after inotropic stimulation by acti-

vating contractile reserve. The principle of low-dose dobutamine stress is

to assess contractile reserve, i.e. look for evidence of improvement in wall

motion abnormalities or clear inotropic response in areas that are thought

to have coronary stenoses (Fig. 10.11). The need for viability assessment is

usually to determine the value of performing revascularization.

Dobutamine infusion

• Start the infusion at 5microgram/kg/min dobutamine.

• Continue the infusion for up to 5min and then increase to 10microgram/

kg/min. This can be increased to 20microgram/kg/min (Fig. 10.12).

• A 10% increase in heart rate marks the end of the low-dose protocol.

• After completing the low-dose protocol higher doses of dobutamine

(30 and then 40microgram/kg/min for 5-min periods) may be given

to look for a biphasic response (improved contraction at low dose

followed by reduced contraction at peak).

• The presence of a biphasic response indicates inducible myocardial

ischaemia and is perhaps the strongest predictor for recovery of

myocardial dysfunction following revascularization. It will indicate a

viable but jeopardized myocardial region.

Image acquisition

A full set of images should be recorded at:

• Baseline.

• Low stress (10% increase in heart rate).

• High stress (if performed).

LOW DOSE DOBUTAMINE

SCAR or LIMITED VIABILITY

SIGNIFICANT VIABILITY

1. No improved wall motion

1. Improved wall motion in

or <4 segments improve*

>4 segments improve*

2. Diastolic wall thickness <0.6cm

2. Diastolic wall thickness >0.6cm

3. End-systolic volume >140mL**

3. End-systolic volume <140mL**

HIGH DOSE DOBUTAMINE

INTRAMURAL SCAR

HIBERNATION

1. No change in wall motion

1. Ischaemic response

2. Worsening wall motion

*Improvement in ≥4 segments is a good predictor for recovery of left ventricle

function after coronary revascularization in patients with hibernating myocardium.

** End systolic volume >140mL indicates an advanced stage of remodelling.

Revascularization may not result in reverse remodelling.

Fig. 10.11 Viable or non-viable?

618

CHAPTER 10 Stress echocardiography

Vasodilator stress

Vasodilator stress echocardiography should only be considered when

physical stress is not possible and there are contraindications to dob-

utamine. It is less sensitive for identification of mild to moderate coronary

artery disease. Vasodilator stress, however, may become more important

as perfusion imaging becomes more widely clinically applicable.

Vasodilators are effective because they induce regional variation in cor-

onary blood flow. Dipyridamole or adenosine cause a 2- or more fold

increase in myocardial blood flow in segments supplied by normal coro-

nary arteries whereas in segments supplied by stenotic arteries flow is

unchanged or decreased. If oxygen demand increases with flow changes,

regional abnormalities in wall motion and thickening appear.

Because vasodilator stress acts via change in perfusion, theoretically, it

should be more suitable for direct assessment of myocardial perfusion

using contrast echocardiography.

Dipyridamole protocol for myocardial ischaemia

The protocol for dipyridamole is based on continuous ECG and echocar-

diographic monitoring during a 2-stage infusion.

Infusion

• Check for contraindications to dipyridamole.

• Initially infuse 0.56mg/kg of dipyridamole over 4min.

• Monitor for 4min. If there are no adverse effects and no clinical or

echocardiographic endpoints occur (significant anginal symptoms, wall

motion abnormalities) infuse 0.28mg/kg over 2min.

• As with dobutamine (b p.614 and Fig. 10.13), atropine (doses of

0.25mg up to a maximum of 1mg) can be used after the second stage

to increase heart rate and improve sensitivity.

• Aminophylline (240mg; IV) should be available for immediate use in

case of an adverse dipyridamole-related event.

Imaging

Imaging should be performed continuously, and images captured at base-

line, end of phase 1, end of phase 2 (if performed), and during recovery.

The minimal images are baseline and hyperaemia. When ultrasound con-

trast is used during the stress test (indicated for improved endocardial

definition) myocardial opacification can be assessed in addition to LV wall

motion (see b p.582).

Adenosine protocol for myocardial ischaemia

Adenosine works on a 6-min protocol with ECG and echocardiographic

monitoring.

Infusion

• Check for contraindication to adenosine.

• Infuse at a maximum dose of 140microgram/kg/min over 6min.

• Stop the infusion if clinical or echocardiographic endpoints are reached

(limiting symptoms or wall motion abnormalities).

620

CHAPTER 10 Stress echocardiography

Pacing stress

• This may be considered in patients with a permanent or temporary

pacemaker.

• Pacing by temporary intravascular or oesophageal leads is usually not

needed for clinically-indicated stress echocardiography.

• In most paced patients exercise, dobutamine, and vasodilator

protocols are applicable.

• Pacing stress can be considered when an increase in heart rate cannot

be achieved by exercise or dobutamine. Since pacing alone only

produces chronotropic stress, it is usually considered to have lower

sensitivity than the inotropic and chronotropic stress achieved by

pharmacological stress.

• Dobutamine can be given at the same time as increasing the pacing

rate to create both chronotropic and inotropic stress.

Pacing protocol

• Pacing stress should preferably be performed with atrial pacing to

ensure natural ventricular contraction and to avoid pacing-induced wall

motion abnormalities.

• In patients with permanent pacemakers, ensure the assistance of a

pacemaker programmer and experienced operator.

• Record baseline images.

• Start pacing at 100bpm.

• Increase every 2min by 10bpm until the target heart rate (85% of

age-predicted maximal heart rate) is achieved or until other standard

endpoints are reached.

• After reaching target heart rate, reduce heart rate every minute by

20bpm till baseline heart rate is reached.

Image acquisition

• Record baseline images and then at every stage and in recovery.

622

CHAPTER 10 Stress echocardiography

Analysis

Echocardiographic recordings have to be evaluated during image acquisi-

tion in order to assess for echocardiographic endpoints. This should be

followed by a comprehensive assessment after the stress test with side-

by-side comparisons of recordings captured at baseline and stress.

Stress echocardiograms can be analysed on several planes of complexity,

which range from a qualitative assessment of segmental wall motion in

response to stress, to highly detailed schemes for quantitative analysis.

For image interpretation, multiple cine loop display allows up to 4 differ-

ent stress levels for each imaging plane to be displayed simultaneously.

Standard review

• Start with assessment of image quality. Endocardial border definition

can be used as an indicator of image quality. If endocardial border

is not seen or is barely visible, wall motion and thickening cannot

be reliably assessed in this segment. Grade image quality as good,

acceptable, or poor and identify non-diagnostic segments.

• On resting images assess global function by LV ejection fraction using

a visual estimate or from measuring end-diastolic or end-systolic

volumes in 2 apical views.

• Compare rest and stress images for the development of global LV

dysfunction (left ventricular enlargement and shape changes) and

remeasure global function at stress if there appears to be a change.

• Then evaluate segmental wall motion at rest and at each level of stress

using a 16- or 17-segment model. Use a 4-step visual score for each

segment: 1—normal, 2—hypokinetic, 3—akinetic; 4—dyskinetic.

• Calculate a wall motion score at each stage, if required, to facilitate

serial comparison. Divide the sum of the points by the number of

segments analysed. Normal contraction has a wall motion score of 1;

a higher score indicates wall motion abnormalities.

• For assessment of myocardial viability wall thickness is useful. Diastolic

wall thickness <5mm at rest indicates non-viability and increases

diagnostic confidence in combination with absent contractile response

to dobutamine.

• If using contrast during stress echocardiography, it may be useful to

assess the myocardial contrast enhancement. With current knowledge

the results of perfusion imaging should be used in conjunction with the

findings of visual left ventricular wall motion analysis.

• The adequacy of stress should be noted and records kept of the

exercise time, symptoms, haemodynamic observations, and ECG

changes.

ANALYSIS

623

Stress echo training

EAE recommends performing at least 100 exams under the supervision

of an expert reader in a high-volume laboratory, and ideally with the

possibility of angiographic verification, before starting stress echocardi-

ography on a routine basis. Maintenance of competence requires at least

100 stress echo exams per year.

Audit and quality control

It is usually accepted that operators should interpret a minimum of 10

stress echocardiograms per month to maintain interpretational skills and

sonographers should perform a minimum of 10 stress echocardiograms

per month to maintain an appropriate level of skill.

Regular audits are useful to review the quality and accuracy of the stress

echocardiograms. The audit should include the total number of stress

echocardiograms performed per month for the time period audited: the

number of procedures per sonographer and reads per physician; indica-

tions; imaging technology; use of contrast; stress protocols; quality of the

studies; termination criteria; results (negative or positive for assessment

of ischaemia, viable or non-viable for viability studies); and complica-

tions. For those patients undergoing coronary angiography, it would be

ideal to have the results of coronary angiography for quality control with

routine review of false positive and negative findings.

Future technologies

Echocardiography technology is progressing rapidly and has been devel-

oped to ensure assessment of left ventricular wall motion is more objec-

tive. Automatic wall tracking software, tissue Doppler imaging, and strain

imaging are becoming clinically viable. The use of tissue Doppler velocity

measurements during stress echocardiography allows the identification

of post-systolic shortening—a known sign of regional ischaemia—which

can be used in order to increase the sensitivity of the test. However, no

data currently demonstrate the superiority of quantitative techniques

over conventional wall motion analysis for the assessment of viable and

ischaemic myocardium. 3D echocardiography has introduced a further

exciting option for stress echocardiography with rapid acquisition of 3D

volume datasets and reconstruction of 3D motion. The lower spatial

and temporal resolutions of 3D imaging are limitations of the current 3D

technique. However, 3D imaging eliminates apical foreshortening, which

is common with 2D imaging, and may improve the detection of apical

wall motion abnormalities. Moreover, 3D imaging generally shortens the

time required for acquisition of stress images.

624

CHAPTER 10 Stress echocardiography

Sample report

Section 1. Demographic and other information

All the standard demographic details should be included. Stress echocar-

diography should also include:

• The clinical indication, including relevant clinical history and

medications. This provides justification for the study and summarizes

clinical information from a number of sources to focus the final

conclusion.

• The stress protocol and imaging technique used with justification,

including the name and dosage of contrast agents.

• Changes of blood pressure and heart rate should be described briefly.

Reporting resting and peak stress blood pressure is usually sufficient.

• For exercise and dobutamine stress echocardiography the age, sex,

and specific target heart rate should be included.

• Further measurements or details of ECG changes can be included if

relevant.

Section 2. Description of observations and diagnostic

statements

• Start with a statement about the completeness of the study and image

quality, since diagnostic confidence heavily depends on high-quality

recordings.

• Next report the baseline analysis. If global and/or regional left

ventricular function is abnormal, the segments involved and the

degree of abnormality (hypokinetic, akinetic, dyskinetic) should be

demonstrated or listed. Schematics of the single views help to illustrate

the distribution of wall motion abnormalities. Non-diagnostic segments

can be marked (Fig. 10.14).

• Then report each of the stress recordings in the same way describing

whether there was a normal response to stress or abnormal response

with worsening wall motion. Segments that deteriorate should be

listed or marked on the schematic and degree of abnormality noted.

• In viability studies it is important to evaluate whether the akinetic

segments show improvement during stress.

Section 3. M-mode, 2D, and Doppler measurements

In stress echocardiography this section will include quantitative measures

of LV function (e.g. ejection fraction) at baseline and on stress. There may

also be information on left ventricular outflow velocities in patients with

suspected stress-induced gradients or changes in mitral valve function. If

tissue Doppler imaging or other analysis methods were used these can

be documented.

Section 4. Conclusions

The conclusion should comment on any suboptimal aspect of the study

(e.g. image quality, target heart rate reached, etc.) and any complica-

tions or adverse events. It should then address the clinical question and

detail the main abnormalities that occurred during stress, or summarize the

response as normal.

628

CHAPTER 11 Acute echocardiography

‘Front door’ echocardiography

Practice development

The last decade has seen the rapid development and refinement of port-

able echo technology. A simultaneous growth in interest in non-invasive

diagnostic tools has driven a worldwide development of transthoracic

echocardiography. As a result it has become a vital skill for those involved

in acute patient care.

• ‘Acute echocardiography’ refers to the use of echocardiography at the

bedside in the acute management of patients receiving urgent care in

ward-based, high-dependency and critical care settings.

• The majority of this patient population do not have artificial airways

and may have limited, established, invasive monitoring, particularly

if they have become acutely unwell. Transthoracic echo therefore

becomes an invaluable and powerful tool for rapid non-invasive

haemodynamic assessment.

• This chapter focuses on the use of transthoracic echocardiography in

the acute setting. This ‘front door’ echocardiography often operates in

time critical situations and relies on more limited types of equipment

with more focused data acquisition than might be expected in full

echocardiographic studies. Local practice, and acceptability, may

therefore vary and therefore local guidelines for use should be

established.

A unique role for echocardiography

• The unique value of this tool comes from the fact it provides direct

assessment of acute cardiac function combined with diagnostic

echocardiographic information.

• Acute echocardiography is most powerful when viewed as part of

a global patient assessment allowing full integration of clinical and

echocardiographic findings.

• Acute echocardiography supports and augments:

• Peri-arrest and resuscitation care.

• Acute medical and trauma diagnostics.

• Stabilization and management of the critically ill.

630

CHAPTER 11 Acute echocardiography

Safeguarding patient care

Practice safety framework

• Where a new practice is being established to provide acute

echocardiography it is essential that the practitioners delivering the

service have a level of echocardiographic expertise that allows them

to make independent, and correct, clinical decisions based on their

images.

• Therefore the service needs to develop approaches for appropriate

operator training and accreditation.

• The individual arrangements for experience and training in an acute

echocardiography service will vary between institutions, but, for many,

this may be best achieved with a service that has some devolved

autonomy from the parent cardiology echocardiography department.

Governance pathways

• As with any investigation that is routinely performed within a

department effective clinical governance pathways must be established.

• This should include:

• Systems for reporting and storing studies whilst maintaining patient

confidentiality.

• A forum for reviewing images with the parent cardiology

department.

• Established pathways to obtain urgent expert help.

• Identification of a service lead to coordinate clinical governance.

Technology

• A primary requirement for the establishment of an acute

echocardiography service will be acquisition of appropriate echo

equipment.

• A good starting point is to align equipment with the parent cardiology

department. This reduces operator errors and improves technological

compatibility, for example, where sharing image storage systems.

SAFEGUARDING PATIENT CARE

631

Echocardiography training in the UK

Resuscitation echocardiography

There are a number of courses available in the UK; for example Focused

Echocardiographic Evaluation in Life Support (FEEL) and Focus Assessed

Transthoracic Echo (FATE). Prior to attending a course we recom-

mend that a mentor is identified who will review and sign off the studies

required to complete the log-book to the expected standard. Time

investment from the mentor should be between 1-2 hours per 10 stud-

ies performed by the candidate. A time frame of 6 months is expected

to complete the accreditation process. Certification entitles the opera-

tor to perform transthoracic studies in the arrest setting provided that

they maintain reasonable competence. Practice must remain within the

resuscitation framework.

Accreditation with the British Society of Echocardiography

Full transthoracic accreditation allows the operator to function as

an independent practitioner and to perform comprehensive studies.

Accreditation requires completion of a log-book of 250 specific cases,

a written examination, and submission of 5 selected recorded studies

illustrating specific pathologies. Completion of the accreditation process

requires a significant time commitment from the operator over a 2-year

period and provision of departmental supervision and training. Following

achievement of accreditation, re-certification is required 5-yearly with

demonstration of continued echo practice and learning.

Contemporary training issues

The qualifications described were not designed to address the spe-

cific practice requirements of clinicians working in acute care areas.

At the time of writing in the UK the representative societies of

Emergency Medicine, Acute medicine and Critical Care, in partnership

with the British Society of Echocardiography, are individually considering

certification processes to address clinicians’ requirements and support

the practice of acute echocardiography. It is likely that these certification

processes will become available in the next 2 years. For more informa-

tion please see the website of the relevant society:

• Acute Medicine: M http://www.acutemedicine.org.uk

• Emergency Medicine: M http://www.collemergencymed.ac.uk

• Critical Care Medicine: M http://www.ics.ac.uk

632

CHAPTER 11 Acute echocardiography

Cardiopulmonary resuscitation

Introduction

• Although there are a number of courses providing training in peri-

resuscitation echocardiography Focused Echocardiographic Evaluation

in Life Support has been developed as a consensus approach for the

UK and is endorsed by both the British Society of Echocardiography

and the Resuscitation Council.

• The FEEL algorithm guides the operator through rapid

echocardiographic assessment during resuscitation using the Advanced

Life Support protocol.

• The aim of the protocol is to identify reversible causes of cardiac

arrest:

• Cardiac tamponade.

• Gross left ventricular overload and failure.

• Gross hypovolaemia.

• Massive pulmonary embolus.

• No measurements, colour imaging, or Doppler are used during the

protocol; diagnosis relies solely on the operator’s ability to observe

pathology accurately.

• Echocardiographic assessment must be performed during the 10-s

pulse check after 5 cycles of CPR and repeated only after completion

of a further 5 cycles.

• Echocardiography must not delay the return of chest compressions.

The FEEL protocol

• The FEEL protocol is based on 4 views:

• Parasternal long axis.

• Parasternal short axis.

• Apical 4-chamber.

• Subcostal.

• It may be unnecessary to obtain all views: a single view may be

adequate if diagnostic.

• The flow diagram in Fig. 11.1 can be used as a guide to asking pertinent

clinical questions in a logical order during the resuscitation, the

implications of key findings and urgent management.

Tips for success

• Clarity of communication is key to obtaining a useful echo study in

this situation.

• Ensure the machine is set up and ready to go before approaching the

patient.

• Negotiate the correct time to perform echocardiography with the

team leader.

• Ask the time-keeper to count 10sec out loud while you perform the

study.

• Communicate your findings to the team aloud.

• Do not compromise patient care: if you cannot locate adequate

images obtain senior help.

Step 1: Is there evidence

If pericardial fluid is present:

of pericardial fluid?

drain immediately.

If the ventricle is still: this

Step 2: Is the left ventricle

If the ventricle is mobile: a

indicates true pulseless

If hypovolaemia is suspected give

mobile or still?

small left ventricular cavity

electrical activity and

aggressive fluid therapy.

indicates hypovolaemia.

ventricular standstill.

If the ventricle is minimally mobile:

Step 3: If the ventricle is

ventricular dilatation indicates left

mobile and not

ventricular failure.

underfilled: is the right

ventricle severely dilated?

If the right ventricle is severely dilated:

If the right ventricle is not dilated:

is there paradoxical motion of the left

consider needle thoracocentesis for

ventricular septum?

the treatment of tension

pneumothorax.

Either or both of these findings should

prompt consideration of thrombolytic

therapy for massive pulmonary

embolus.

Fig. 11.1 Flowchart for FEEL algorithm.

634

CHAPTER 11 Acute echocardiography

Acute diagnostics

Diagnostic transthoracic echocardiography in the acute setting plays a par-

ticular role in the diagnosis and management of the patient presenting

with:

• Acute shortness of breath.

• Suspected cardiac tamponade.

• Suspected sub-massive pulmonary embolus.

• Low cardiac output states.

• Clinical acute coronary syndromes.

• Blunt and penetrating thoracic trauma.

Transthoracic echocardiography is urgently indicated to assist in management

decisions relating to:

• Thrombolysis in sub-massive pulmonary embolism.

• Urgent percutaneous coronary intervention in acute coronary

syndromes.

• Drainage of pericardial fluid in cardiac tamponade.

• Management of acute cardiac failure.

• Transfer to cardiothoracic theatre for operative management of

mechanical problems.

A full BSE minimum dataset should be the aim of all transthoracic studies

in this setting. However, given the need for urgent management triggered

by some echocardiographic findings, completion of a full study should not

delay patient management. Fig. 11.2 outlines a practical guide to echocar-

diology in the acutely unwell patient.

It is good practice to repeat the echo study following patient stabilization to

ensure a full dataset is achieved whenever possible and to record echocar-

diographic correlation with signs of improvement in the patient’s clinical

state.

Tips for success

• Optimize patient comfort and safety prior to attempting a study: for

example, ensure they have adequate oxygen to maintain saturations

and they are not in pain.

• Optimize patient position prior to commencing the study wherever

possible: for example, left lateral position can be maintained with

pillows, ask for help in turning the patient into a suitable position

to optimize views, ask for assistance in maintaining the left arm in a

suitable position.

• Be prepared: time available to perform a study may be limited. Think

about what you need to look for and exclude in a systematic fashion

using the protocol given in Fig. 11.2.

• Minimize time wasted: prepare the machine before optimizing patient

position.

• Utilize all available acoustic windows to achieve answers to clinical

questions: diagnostic acoustic windows can be achieved in 90-95% of

acute cases.

ACUTE DIAGNOSTICS

635

Step 1: Exclude

In a trauma situation:

pericardial fluid.

Notes: Ensure depth

In a non-trauma

The presence of fluid in

is adequate.

situation:

the pericardium in blunt

or penetrating chest

Assess for signs of

trauma should prompt

cardiac tamponade

IMMEDIATE assessment

Step 2: Categorise

by the cardiothoracic

global LV function.

If absent return to

team.

Notes: Use qualitative

step 2 & complete study.

or quantitative methods.

Following urgent referral

If present stop study

return to the patient: if

and contact cardiology

appropriate to continue the

Step 3: Assess each

and appropriate

study examine the aorta

wall region.

supportive teams urgently.

for signs of dissection and

then continue from step 2.

Septal dyskinesia

Other wall

Step 3a: Consider management as

motion

ACS if appropriate clinical context.

abnormality

Contact cardiology team and

appropriate supportive teams urgently.

Step 4: Assess the RV

free wall size and function.

Image the pulmonary

Notes: RV dilatation and

failure should prompt:

Step 3b: Make as specific search for:

arteries to exclude

Assessment of TR jet

VSD

visible thrombus.

Estimation of PAP

Papillary muscle dysfunction/rupture.

Categorise RA as dilated

Continue from step 4.

or non-dilated

Evidence of acute RV

Red arrows indicate pathological

pressure and volume

findings and specific relevant

overload supports

Step 5: Assess AV

pathway.

the decision to

opening and regurgitation.

thrombolyse a

pulmonary embolus

in the context of a

compatible clinical

Step 6: Assess MV

presentation and

opening and regurgitation.

evidence of

cardiovascular

compromise.

Step 7: Assess TV

forward flow &

regurgitation.

Step 8: Assess PV

forward flow &

regurgitation.

If no abnormality is found

assess fluid balance using

the flow diagram shown

overleaf.

Fig. 11.2 Transthoracic echocardiogarphy thought process in the acutely unwell

patient.

636

CHAPTER 11 Acute echocardiography

Critically ill: volume status

Dynamic fluid balance can be effectively assessed using transthoracic

echocardiography. The more profound the hypovolaemia or hypervolae-

mia the easier it is to demonstrate with echocardiography and the more

parameters assessed the more accurate the evaluation.

• Fig. 11.3 and Table 11.2 provide details of the key parameters and

imaging process that can help differentiate between hypovolaemia,

normal volume status and volume overload. The key parameters to

assess are:

• IVC diameter and response, and right atrial size.

• Parameters of left and right ventricular size.

• Change in measurements is of particular value. Therefore compare

with previous images whenever possible and repeat assessments

after therapy (diuresis or fluid) to determine whether fluid status is

changing.

• Beware of:

• Pre-existing regional wall motion abnormalities and chronic

chamber dilatation: these will alter the measurements and reduce

their value for assessment of volume status.

• Body size: dimensions should be adjusted for body surface area

(BSA) where possible:

BSA (m2) = √([Height(cm) × Weight(kg)]/3600)

Assessment of the inferior vena cava and right atrium

In spontaneously breathing patients the degree of collapse with inspiration

correlates well with right atrial pressure. However, right atrial pressure

itself only becomes an accurate assessment of volume status when signifi-

cantly high or low (Table 11.1).

Measuring the IVC

• Use the subcostal view and get the vessel in its long axis (though a

cross-section can be used).

• Measurement of IVC size should be taken 1-2cm below the entrance

to the right atrium if possible, just above or below the hepatic vein.

• Accurate measurement in 2D requires the vessel to be followed

throughout the respiratory cycle, keeping the junction of IVC and

hepatic vein in view. If using 2D then you may need to capture 5 or

more beats depending on the respiratory rate.

• M-mode gives better resolution and allows easy visualization of several

cycles but keeping the vessel in view can be more difficult.

Measuring the right atrium

• Area measures are acquired from apical 4-chamber views.

• Beware of long-standing right atrial dilatation that will make

correlations between size and right atrial pressure inaccurate.

CRITICALLY ILL: VOLUME STATUS

637

Volume Status

Assess the Inferior

Subcostal view

Vena Cava

Measure maximum diameter.

Gauge diameter change with respiration.

Check for hepatic vein dilatation.

In any view

Visually assess the LV - small and hyperdynamic suggests hypovolaemia.

Assess the Left

Papillary apposition suggests severe hypovolaemia.

Ventricle

Parasternal view

Look for causes of dynamic outflow obstruction: severe LVH, HOCM,

subaortic bulge.

Separation of the Anterior Mitral Valve leaflet tip

(End-Point Septal Separation) from the septum in diastole.

Measure the end diastolic internal dimension and calculate LVIDd/BSA

In PSAX measure end diastolic area index by plamimetry and calculate

Assess the Right

LVEDAI.

Atrium

Apical view

Where there is suspicion of dynamic outflow tract obstruction use

Continuous-Wave Doppler to assess LVOT gradient.

Measure LVEDAI if not done already or, if time allows, measure

End-Diastolic Volume using Simpson’s biplane method.

Look for dilatation - measure at least 2 RV dimensions from any of the

standard views.

Assess the Right

Parasternal view

Ventricle

In PSAX, look for septal flattening causing a ‘D’-shaped LV, suggesting

RV volume overload.

If flattening present, does it extend into systole? Is there clinical

suspicion of pulmonary embolism?

Apical view

Visually assess the RV and estimate RV/LV ratio.

Estimate RV systolic function using lateral Tricuspid annulus longitudinal

excursion (normal TAPSE is more than 1.8cm) or using tissue Doppler

at the same point (normal is more than 10 m/s).

Fig. 11.3 Emergency assessment of inferior vena cava, left ventricle, right atrium,

and right ventricle to guide volume status.

Table 11.1 Assessment of right atrial pressure

RAP (mmHg)

0-5

5-10

10-15 15-20 >20

IVC size (cm)

<1.5

1.5-2.5

1.5-2.5 >2.5

>2.5

Respiratory variation Collapses >50% collapse <50%

<50% No

change

638

CHAPTER 11 Acute echocardiography

Assessment of the left ventricle

A very under-filled

(small, cavity obliteration in systole) or severely

dilated (large) left ventricle is easy to spot, but for more subtle states the

measurement of dimensions and incorporation with other measures is

imperative (Fig. 11.3).

A significant amount of information can be derived from measurements of

left ventricular cavity size. The key measures that reflect cavity size are:

• Left ventricular internal diameter in diastole (LVIDd) (see b p.196).

• Left ventricular end-diastolic area index (LVDAI) (See Table 11.)—this

is left ventricular area in the short axis normalized for BSA.

• End-point septal separation—this is measured from the M-mode trace

at the level of the mitral valve and represents the distance between

the top of the first peak (E wave) of the mitral valve opening to the

interventricular septum. It increases with both ventricular dilatation

and reduced function (normal 6mm).

• Left ventricular end-systolic diameter (see b p.196).

Hypovolaemia can convert lesser degrees of left ventricular hypertrophy

into effective outflow obstruction because of the reduction in size of the

end systolic left ventricular cavity.

Assessment of the right ventricle

Right ventricular dimensions can be measured in several different views so

it is usually possible to get at least one accurate measurement. Standard

measures should ideally be used (Table 4.6) or simplified ‘rules of thumb’

can be found in Table 11.3.

• Acute dilatation implies pressure or volume overload. The common

causes for this in the critically ill include pulmonary embolus and acute

lung injury or acute respiratory distress syndrome; less common are

right ventricular infarction or acute tricuspid valve disease.

• In RV dilatation the right ventricular output is unlikely to be preload

dependent, making detailed fluid balance decisions difficult.

• Diastolic flattening of the interventricular septum occurs with acute

RV volume overload.

• Diastolic and systolic flattening suggests more severe volume overload

or the existence of RV pressure overload. (see b p.276).

• Severe dilatation is usually accompanied by systolic dysfunction and at

least moderate TR.

• Beware of long-standing RV dilatation that makes inferences

concerning size difficult in the acute setting.

CRITICALLY ILL: VOLUME STATUS

639

Table 11.2 Parameters to help identify fluid status

Suggests

Normal range

Suggests volume

hypovolaemia

overload

IVC diameter

<1cm and

1-2.5cm, collapsing >2.5cm, no response

and response

collapsing

25-75%

to respiration

LVIDd/BSA

<2.4 women

2.4-3.2

>3.2

(cm/m2)

<2.2 men

2.2-3.1

>3.1

LVEDAI

<5.5

5.5-10

>10

(short axis)

End point septal

<0.5m

>0.5cm

separation

LVESD

Papillary

2.0-4.0cm

apposition

RV internal

See below

RVIDd >LVIDd

dimensions

Interventricular

No flattening

Diastolic flattening

septum

Right atrium

<20cm2

>30cm2

Table 11.3 Right ventricular dimensions

Normal range (cm)

PLAX

AP dimension: 1.8-3.0

PSAX

RVOT: 2.0-3.2

A4C

TV annulus: 1.6-3.1

Mid RVIDd: 2.4-3.7

RV length (diastole): 6.9-8.9

640

CHAPTER 11 Acute echocardiography

Critically ill: fluid responsiveness

Any method of measuring change in stroke volume or cardiac output can

be used to assess whether a patient responds to a given volume of fluid.

Being able to predict whether a patient is likely to respond to that fluid

(‘fluid responsive’) is even more useful as it can avoid the potential detri-

mental effect of excessive fluid administration.

• The term ‘fluid responsive’ implies that stroke volume will increase by

10-15% when a fluid load is delivered (usually 500mL, or 70-80mL/kg,

of crystalloid or colloid given rapidly).

• Dynamic indicators of fluid responsiveness (such as parameters that

change with respiration or patient position) are significantly more

accurate than static (such as end-diastolic volumes).

• Mechanical ventilation allows more reliable assessment of the

likelihood of fluid responsiveness.

IVC

Assessment of fluid responsiveness using the IVC is only reliable during

mechanical ventilation. In this situation if the IVC collapses by >20% then

the patient should respond to fluids (Fig. 11.4). In spontaneous ventilation

complete collapse during inspiration is consistent with fluid responsive-

ness but may be confounded by respiratory effort and state of the right

heart.

Left ventricle

A simple way to assess fluid responsiveness is to assess for variation in

flow across the aortic valve or LVOT with different manoeuvres:

• Variation with respiration: variation with respiration in the vti across

any valve or outflow tract can be used. However, the best validated

method is flow variation across the aortic valve or LVOT. A change

in left heart flow of >10% suggests the patient is likely to be ‘fluid

responsive’.

• Passive leg raising: Change in the vti (and therefore stroke volume)

after passive leg raising is another method of fluid responsiveness

assessment. This works because raising the legs effectively redistributes

blood from the legs to the thorax which mimics a fluid challenge.

To do a ‘passive leg raise’ raise both of the patient’s legs to 45° for

1-2min. A change in SV of 720% suggests fluid responsiveness.

Dysrhythmias reduce the utility of these measurements, but if present,

then at least 3 or more representative waveforms should be recorded and

the results then averaged.

CRITICALLY ILL: FLUID RESPONSIVENESS

641

<1.5cm - fluid response likely

Spontaneous ventilation:

Measure diameter in

expiration.

>1.5cm - uncertain significance

Assess

IVC

No spontaneous ventilation:

Measure minimum and

>18% - fluid response likely

maximum diameter during

ventilation.

<15% - fluid response unlikely

Calculate distensibility using:

100 x (Dmax − Dmin)/Dmin.

If a passive leg raise is

possible:

In A4C, A5C or angled sub-

costal view sample the LVOT

with PWD and measure vti

>15% - fluid response likely

(ideally average the smallest

and largest).

<10% - fluid response unlikely

Assess

Repeat after raising the legs

45* (or by reclining the

patient).

Calculate increase in integral.

Fig. 11.4 Assessing fluid responsiveness.

642

CHAPTER 11 Acute echocardiography

Critically ill: advanced haemodynamics

A number of measurements may be of use in the critically ill both for

diagnosis and to guide fluid, inotrope or vasopressor therapy (Fig. 11.5).

Serial focused assessments can eliminate the need for invasive monitoring

in some instances.

Stroke volume (SV) and cardiac output (CO)

Stroke volume can be measured using PW Doppler of the LVOT (or

the RVOT) combined with measurement of the outflow tract diameter

(b p.230). Alternatively, it can be determined measuring change in area of

the ventricle. CO is then derived from multiplying SV by heart rate. When

assessing these parameters with echo beware:

• An accurate measurement of the outflow tract diameter is required as

any error will be squared in the calculation.

• A clear Doppler trace, properly aligned through the aortic valve and

LVOT is required, as a suboptimal trace may underestimate true

velocities.

• Significant MR or TR will lead to inaccuracies in measurement of

stroke volume based on PW Doppler in the outflow tract as it will not

take account of the volume of blood that regurgitates into the atria.

Systemic vascular resistance (SVR)

SVR measurements can be used in diagnosis of underlying causes for

haemodynamic problems, e.g. sepsis will lower systemic vascular resist-

ance. Changes in systemic vascular resistance can be used as a guide to

effectiveness of vasopressor therapy or changes in clinical status.

• To calculate SVR measure cardiac output, the mean arterial pressure,

and the right atrial pressure. Then use the equation

SVR = 80 × (MAP − RAP)/CO

5).

Left atrial pressures (LAP)

Approximate LAP is most accurately confirmed by Doppler assessment

of the MV inflow and annular tissue velocity, or by pulmonary vein

flow pattern. The measure closely reflects LVEDP (see b p.644). The

two measures are therefore often discussed interchangeably but are

presented in this chapter under both ‘titles’. E/E’ (septal) >15 suggests

severely elevated LAP. A predominant and increased D wave in the

pulmonary vein flow also suggests elevated pressures (a pre-dominant

D wave is also seen in patients with severe mitral regurgitation although

this is also, in part, due to a reduction in size of the S wave).

CRITICALLY ILL: ADVANCED HAEMODYNAMICS

643

Using Doppler

In A4C, A5C or angled sub-costal view sample

the LVOT using Pulsed Wave Doppler.

Trace a representative waveform to measure the

velocity-time integral in cm.

Measure the LVOT diameter in cm.

Stroke Volume in mL = VTI x 3.14 x (LVOT

diameter/2)²

Stroke Volume

If the LVOT view is poor use the RVOT in the

and

PSAX or sub-costal view.

Cardiac Output

Cardiac output is the product of heart rate and

stroke volume.

Using volumetric method

Simpson’s biplane method gives a an end-

systolic and end-diastolic volume from which

SV can be calculated.

Assess using Cardiac output, blood pressure and

CVP:

Measure the Cardiac output as detailed above.

If RAP is not known then estimate it using the

dimension and degree of collapse of the IVC.

Use the equation SVR = (MAP-RAP)/CO (in

Systemic

mmHg and L/min respectively)

Vascular

Normal SVR = 800-1200 dyne.sec/cm⁵

Resistance

A qualitative assessment can be made using

CWD assessment of the maximum velocity of an

MR jet, if present:

MR V_max/VTI1

A result of more than 0.27 suggests high

resistance, <0.2 normal.

Fig. 11.5 Advanced haemodynamics.

644

CHAPTER 11 Acute echocardiography

Estimated LV end-diastolic pressure (LVEDP)

LVEDP is useful in both the differentiation of pulmonary oedema from

acute lung injury and estimating adequacy of preload. In pulmonary oede-

ma LVEDP will increase whereas in acute lung injury it will decrease or not

change. In estimation of preload, LVEDP will decrease as preload reduces.

In the acute setting measures based on aortic or mitral regurgitation have

been used. In the non-acute setting measures based on tissue Doppler

imaging and pulmonary vein flow are routinely used to evaluate LVEDP

to aid diagnosis of diastolic dysfunction and HFNEF (see Chapter 3).

Estimated LV end-diastolic pressure also closely reflects left atrial pres-

sure (see b p.642).

• To measure LVEDP based on valvular regurgitation obtain a Doppler

trace of the aortic regurgitation and measure the velocity at the end of

the regurgitation trace. Get a measure of diastolic blood pressure at

the same time as your measurement and then use the equation:

LVEDP = DBP - end aortic regurgitation gradient

• If the patient does not have aortic regurgitation but has some mitral

regurgitation this can also be used to estimate LVEDP based on the

initial slope of the regurgitation Doppler profile (see b p.232).

• To measure LVEDP with tissue Doppler imaging, obtain a TDI trace

based on movement of the mitral annulus in the 4-chamber view and

get a Doppler spectral trace of mitral valve inflow. E/E’ (septal)

<8 suggests a normal LVEDP. E/E’>15 suggests LVEDP is elevated.

Corrected aortic flow time (FTc) and assessment of preload

Corrected aortic flow time can be used to assess preload. An increment

caused by volume loading is a useful marker of fluid responsiveness (see

b p.642). It is however also affected by changes in inotropy and after-

load, and also by the existence of bundle branch block. Normal FTc is

330-360ms. To measure corrected aortic flow time:

• Obtain an apical 5-chamber view (or suprasternal view) and align CW

Doppler across the aortic valve and LVOT.

• On the Doppler tracing measure the duration (in ms) of forward flow

across the aortic valve.

• Then correct this value for heart rate using the equation:

FTc = FT/Square root of R-R interval or

(simplified) FTc = FT + [1.29 x (HR − 60)]

Pulmonary arterial occlusion pressure (PAOP)

PAOP is useful in the assessment of acute lung injury, respira-tory distress

syndrome, and pulmonary oedema. PAOP can be assessed using a visual

analysis of the interatrial septum, or by Doppler echocardiography. In any

appropriate view:

• Watch the movement of the interatrial septum relative to the right

atrium. If:

• Septum persistently bows towards the right atrium PAOP = ~18mmHg.

• Only bows in mid-systole but fully PAOP = ~13mmHg.

• Only bows in mid-systole and only partially PAOP = ~10mmHg.

646

CHAPTER 11 Acute echocardiography

Critically ill: weaning from a ventilator

Difficulty in weaning a patient who has been critically ill from ventilatory

support may occur whenever there is a mismatch between metabolic supply

to the respiratory muscles and demand on those muscles.

The three most common factors affecting this balance are:

• Muscular weakness.

• Poor respiratory drive.

• Inadequate cardiac reserve.

The algorithm in Fig. 11.6 describes the thought processes and actions

through which transthoracic echocardiography can assist in the manage-

ment of the difficult to wean patient.

Tips for success

• Image quality should be maximized by taking time to optimize patient

positioning.

• If previous echo images are available from the acute stages of the

patient’s illness it is important to comment on the comparative

behaviour of the left ventricle in particular. The concept of the ‘acute

ventricle’ is very relevant here. Systolic and diastolic dysfunction in

acute illness from a range of causes including sepsis and polytrauma

may take a variable time to resolve: optimization of the ventricle in

the recovery phase of illness with interval monitoring thereafter is

therefore optimal.

• Assessment of diastolic dysfunction should be based upon transmitral

velocity assessment, tissue Doppler imaging of the mitral annulus,

and PW Doppler assessment of the pulmonary venous inflow.

Valsalva manoeuvre in this patient group will be either impossible or

inadequate.

• This patient group is prone to the development of pulmonary emboli:

clinician-echocardiographers should make a thorough assessment

of pulmonary artery pressure and have a low threshold for further

investigation of this potentially reversible cause of failure to wean.

• The pathway shown should be undertaken in conjunction with a

full assessment of fluid balance as shown in the flow diagram on

b p.639. This assessment should be made alongside clinical enquiry

into fluid balance over the total length of the patient’s illness: acute

assessment of echocardiographic indicators of fluid balance may not

reflect the need for fluid off-loading to facilitate weaning.

When assessing valve

Step 1: Assess LV structure

Significant LVH may suggest diastolic dysfunction.

LV dilatation may correlate with LV systolic

structure and function in the

dysfunction or fluid overload.

critically ill always search for

Where a RWMA is seen

unsuspected vegetations.

Step 2: Assess LV systolic function

Global systolic dysfunction should prompt calculation

RWMA should prompt referral for

of EF and optimisation with rate control and ACEI.

consideration of coronary assessment

exclude VSD and acute MV

or medical therapy.

dysfunction.

Step 3: Assess LV diastolic function

Evidence of diastolic dysfunction should prompt

MS will require cardiology

scrupulous rate control, and ACE inhibition.

referral.

MR should be treated with

Step 4: Assess MV opening

diuretic therapy and rate

and incompetence

control where the patient

is in AF.

Step 5: Assess AV opening and

incompetence

AVG > 40mmHg or valve area < 1.0 cm² should

AR graded as >mild should

Ensure the CE is included in this

prompt cardiology referral.

The finding of significant

assessment since

pulmonary hypertension:

LV function may be abnormal

PAP>35 mmHg should

following critical illness

prompt exclusion

pulmonary emboli and

Step 6: Assess RV dilatation

RV dilatation and reduced annular function should

prompt a search for pulmonary emboli where

Image the pulmonary trunk for

management of the PAP

and function

right sided coronary disease is not suspected.

evidence of thrombus:

with medical therapy.

Where TR is present

Step 7: Assess TV forward flow

measure the RVSP from

and incompetence

several views and

calculate the PAP as a

product of the RVSP and

the RAP estimated from

Step 8: Assess PV forward flow

the behaviour of the IVC

and incompetence

The presence of pericardial fluid in a patient with

Step 10: Assess the IVC

Step 9: Examine the pericardium

previous or current sepsis should prompt

to exclude volume overload

from multiple views

consideration of a pyopericardium.

Fig. 11.6 Thought processes and actions through which transthoracic echocardiography can assist in the management of the difficult to wean patient.

649

Chapter 12

Reporting and normal

ranges

Reporting 650

Left ventricle

652

Left ventricular size, mass, and function

654

Right ventricle

656

Right ventricular size and function

657

Ventricular septum 658

Atrial septum 659

Left atrium 660

Right atrium 660

Atrial size

661

Aortic valve

662

Aortic stenosis

662

Aortic regurgitation

662

Mitral valve

664

Mitral stenosis

666

Mitral regurgitation

666

Tricuspid valve

668

Tricuspid regurgitation

669

Right atrial pressure

669

Pulmonary valve 670

Pulmonary artery 670

Pulmonary regurgitation 671

Pulmonary stenosis 671

Prosthetic valves

672

Prosthetic valve velocities

673

Aorta 674

Aortic size

675

Masses 676

Endocarditis 677

Pericardium 678

Pericardial fluid

678

650

CHAPTER 12 Reporting and normal ranges

Reporting

A standard approach to reporting ensures complete studies, and improves

comprehension for other readers during interpretation or follow-up. Here

we describe a suggested structure for a report and anatomical structures

are listed with examples of appropriate descriptions (b ‘Section 2’, p.650).

The calculations (b ‘Section 3’, p.650) will have been collected as part of

the minimal dataset (described in Chapter 2) and can be interpreted based

on tables of expected values for different anatomy and pathology (these

tables have been replicated in this chapter).

Section 1. Demographic and other information

• Patient’s name, date of birth, gender, hospital number.

• Date on which study was performed.

• Location (inpatient, outpatient) and urgency.

• Indications for test.

• Referring physician.

• Sonographer/physician performing and interpreting the study.

• Height, weight, blood pressure (if available).

• Ultrasound machine and data storage.

• Image quality and any suboptimal views (if applicable).

Section 2. Description of observations and diagnostic

statements

A brief description should be given of each anatomical feature. The descrip-

tion should summarize findings from all views (comments should be able

to be supported from measurements later in report). It is unpractical to

include all statements if everything is normal and usually it is sufficient just

to call them normal in structure and function. However, there should be a

protocol or check list to ensure all comments are based on facts (visual and

quantitative assessment). For each anatomical detail, when appropriate,

there should also be a diagnostic statement, such as, appearances sugges-

tive of rheumatic mitral disease.

Section 3. M-mode, 2D, and Doppler measurements

This section is based on a minimal dataset that should be included in every

report (b p.85), supplemented with additional measures as required to

describe any pathology. Ideally the report should include normal values for

particular measurements.

Section 4. Conclusions

This section is often read first by the referring physicians, who may not

be cardiologists. It has to be easily understood and should summarize

the whole study. Identify any abnormality, its cause (if identifiable) and

any secondary effect. This may involve repeating some of the information

from Sections 2 and 3. The questions of the referring physicians should

be answered. If not possible, then the reasons should be included and

alternative methods suggested (e.g. transoesophageal echocardiography

or contrast echocardiography). Medical advice should be separated from

the report of the study.

REPORTING

651

Sample report: normal

John Smith

DoB: 10:07:1935

Inpatient: Ward A

Height: 182 cm

Weight: 74kg

BP: 120/70

Indication:?LV function

Referring Physician: Dr Smith

Sonographer: John Brown

Interpreting Physician: Dr Jones

Machine: Ultrasound Machine A Images saved: Server

Image Quality: Good

Descriptions

1. Left ventricle: normal cavity size, normal wall thickness, normal

systolic and diastolic funtion

2. Right ventricle: normal size, normal wall thickness, normal systolic

function

3. Ventricular septum: normal

4. Left atrium: normal size

5. Right atrium: normal size

6. Atrial septum: normal

7. Inferior vena cava: normal diameter, normal response during

respiration

8. Aortic valve: normal structure and function

9. Mitral valve: normal structure and function

10. Tricuspid valve: normal structure and function

11. Pulmonary valve: normal structure and function

12. Pulmonary artery: normal diameter

13. Pericardium: no thickening, no effusion

14. Aorta: normal diameter of root and ascending aorta

Measurements

1. Left ventricle

LVED-5.0cm, LVES-3.5cm, FS - 30% IVS-

1.0cm, LVPW-0.9cm normal diastolic LV

function, E' (Medial) 6.9 cm/s, E' (lateral)

10.9, E/E' 12.0

2. Right ventricle

RVED - 2.0cm

3. Left atrium

LA diameter - 3.2cm

4. Right atrium

—

5. Inferior vena cava

—

6. Aortic valve

peak velocity - 1.2m/s

7. Mitral valve

E: A ratio - 1.1

8. Tricuspid valve

TR maximum velocity - 1m/s

9. Pulmonary valve

PW peak velocity - 1m/s

10. Pulmonary artery

Root diameter - 2.6cm

11. Pericardium

—

12. Aorta

Root diameter - 2.7cm

Conclusions

Normal echocardiogram. Normal left ventricle size. Normal left ventricle

systolic and diastolic function.

Dr. Jones

652

CHAPTER 12 Reporting and normal ranges

Left ventricle

Descriptive terms

Cavity size

• Normal, dilated (mild/moderate/severe), decreased.

Wall thickness

• Normal, hypertrophy (mild/moderate/severe).

• Pattern (concentric, eccentric, asymmetric + location)

• Decreased.

LV Mass

• Normal, mild, moderate, severe increase.

Shape

• Normal, aneurysm, pseudoaneurysm (+ location).

Global systolic function

• Normal, borderline, low normal.

• Decreased (mild, mild to moderate, moderate, moderate to severe,

severe).

• Increased (hyperdynamic).

• Estimated ejection fraction.

Regional systolic function

• Normal, hypokinetic, akinetic, dyskinetic, scar.

• Asynchronous, not seen. Describe for each segment of the walls:

• Anterior (basal, mid, apical).

• Anteroseptal (basal, mid).

• Inferoseptal (basal, mid, apical).

• Inferior wall (basal, mid, apical).

• Posterior (inferolateral) wall (basal, mid, apical).

• Lateral wall (basal, mid, apical).

Diastolic filling

• Normal, abnormal (Impaired relaxation, pseudonormal, restrictive).

• Elevated left atrial pressure (E/E’ >15, normal <18).

Left ventricle outflow tract

• No obstruction, obstruction (mild/moderate/severe).

• Septal hypertrophy, subaortic membrane.

• Associated with mitral valve systolic anterior motion.

Thrombus

• Absent, present (+ location and description).

Mass

• Absent, present (+ location and description).

654

CHAPTER 12 Reporting and normal ranges

Left ventricular size, mass, and

function (Tables 12.1 and 12.2)

Table 12.1 Ranges for measurements of LV size and mass

Women

Normal

Mild

Moderate

Severe

LV dimension

LVED diameter, cm

3.9-5.3

5.4-5.7

5.8-6.1

>6.1

LVED diameter/BSA, cm/m2

2.4-3.2

3.3-3.4

3.5-3.7

>3.7

LV volume

LVED vol, mL

56-104

105-117

118-130

>130

LVED vol/BSA, mL/m2

35-75

76-86

87-96

>96

LVES vol, mL

19-49

50-59

60-69

>69

LVES vol/BSA, mL/m2

12-30

31-36

37-42

>42

Linear method: fractional shortening

Endocardial, %

27-45

22-26

17-21

<17

2D method

Ejection fraction, %

>54

45-54

30-44

<30

Linear method: wall thickness

Relative wall thickness, cm

0.22-0.42

0.43-0.47

0.48-0.52

>0.52

Septal thickness, cm

0.6-0.9

1.0-1.2

1.3-1.5

>1.5

Posterior wall thickness, cm 0.6-0.9

1.0-1.2

1.3-1.5

>1.5

2D method

LV mass, g

66-150

151-171

172-182

>182

LV mass/BSA, g/m2

44-88

89-100

101-112

>112

BSA, body surface area; d, diastolic; s, systolic. Bold rows identify best validated measures.

3D LV volume and ejection fraction

Upper normal values (mean + 2 standard deviations [SD])

LV end-diastolic volume index (LVEDVI)

82mL/m2

LV end-systolic volume index (LVESVI)

38mL/m2

Lower limit (mean − 2 SD)

LVEF

49%

EF, ejection fraction; LVEDVI, LV end-diastolic volume index; LVESVI, LV end-systolic volume

index.

LEFT VENTRICULAR SIZE, MASS, AND FUNCTION

655

Table 12.2 Ranges for measurements of LV size and mass

Men

Normal

Mild

Moderate Severe

LV dimension

LVED diameter, cm

4.2-5.9

6.0-6.3

6.4-6.8

>6.8

LVED diameter/BSA, cm/m2 2.2-3.1

3.2-3.4

3.5-3.6

>3.6

LV volume

LVED vol, mL

67-155

156-178

179-201

>201

LVED vol/BSA, mL/m2 35-75

76-86

87-96

>96

LVES vol, mL

22-58

59-70

71-82

>82

LVES vol/BSA, mL/m2

12-30

31-36

37-42

>42

Linear method: fractional shortening

Endocardial, %

25-43

20-24

15-19

<15

2D method

Ejection fraction, %

>54

45-54

30-44

<30

Linear method: wall thickness

Relative wall thickness, cm 0.24-0.42

0.43-0.46

0.47-0.51

>0.51

Septal thickness, cm

0.6-1.0

1.1-1.3

1.4-1.6

>1.6

Posterior wall

0.6-1.0

1.1-1.3

1.4-1.6

>1.6

thickness, cm

2D method

LV mass, g

96-200

201-227

228-254

>254

LV mass/BSA, g/m2

50-102

103-116

117-130

>130

BSA, body surface area; d, diastolic; s, systolic. Bold rows identify best validated measures.

3D LV volume and ejection fraction

Upper normal values (mean + 2 standard deviations [SD])

LV end-diastolic volume index (LVEDVI)

82mL/m2

LV end-systolic volume index (LVESVI)

38mL/m2

Lower limit (mean − 2 SD)

LVEF

49%

EF, ejection fraction; LVEDVI, LV end-diastolic volume index; LVESVI, LV end-systolic volume

index.

RIGHT VENTRICULAR SIZE AND FUNCTION

657

Right ventricular size and function

(Tables 12.3 and 12.4)

Table 12.3 2D parameters to assess right ventricle size and function

(ASE guidelines)

Measure

Abnormal

Chamber dimensions

RV basal diameter (RVD1)

>4.2cm

RV subcostal wall thickness

>0.5cm

RVOT PSAX distal diameter (RVOT2)

>2.7cm

RVOT PSAX proximal diameter (RVOT1)

>3.3cm

Systolic function

TAPSE

<1.6cm

Tissue Doppler peak velocity at the annulus

<10cm/s

Pulsed Doppler myocardial performance index

>0.40

Tissue Doppler myocardial performance index

>0.55

Fractional area change (%)

>35%

Table 12.4 3D RV volumes and ejection fraction

LRV (95% CI) Mean (95% CI) URV (95% CI)

3D RV EF (%)

44 (39-49)

57 (53-61)

69 (65-74)

3D RV EDV indexed (mL/m2) 40 (28-52) 65 (54-76)

89 (77-101)

3D RV ESV indexed (mL/m2)

12 (1-23)

28 (18-38)

45 (34-56)

CI, confidence interval; EF, ejection fraction; EDV, endiastolic volume; ESV, endsystolic volume;

LRV, lower reference value; URV, upper reference value.

658

CHAPTER 12 Reporting and normal ranges

Ventricular septum

Descriptive terms

Abnormal septal motion

• Abnormal (paradoxical) motion consistent with right ventricle volume

overload.

• Abnormal (paradoxical) motion consistent with postoperative status.

• Abnormal (paradoxical) motion consistent with left bundle branch

block.

• Abnormal (paradoxical) motion consistent with right ventricle

pacemaker.

• Abnormal (paradoxical) motion due to pre-excitation.

• Flattened in diastole (‘D’-shaped left ventricle) consistent with right

ventricle volume overload.

• Flattened in systole consistent with right ventricle pressure overload.

• Flattened in systole and diastole consistent with right ventricle

pressure and volume overload.

• Septal ‘bounce’ consistent with constrictive physiology.

• Excessive respiratory change consistent with tamponade, constriction,

ventilation-related.

• Other (specify).

Ventricular septal defect

• Absent, present.

• Location (perimembranous, subpulmonary/doubly committed, inlet,

muscular, multiple.

• Size (small/moderate/large).

• Shunt (left-to-right/right-to-left/bidirectional).

660

CHAPTER 12 Reporting and normal ranges

Left atrium

Descriptive terms

Cavity size

• Normal, dilated (mild/moderate/severe), decreased.

Thrombus

• Absent, present (+ location and description).

Mass

• Absent, present (+ location and description).

Spontaneous contrast

• Absent, present.

Other

• Cor triatriatum, hypoplastic left atrium, consistent with cardiac

transplantation.

Right atrium

Descriptive terms

Cavity size

• Normal, dilated (mild/moderate/severe), decreased.

Thrombus

• Absent, present (+ location and description).

Mass

• Absent, present (+ location and description).

Catheter/pacing wire

• Absent, present.

Right atrial pressure

• Septum bowed to left consistent with elevated right atrial pressure.

• Dilated coronary sinus consistent with elevated right atrial pressure or

left superior vena cava.

• Persistent left superior vena cava.

• Normal inferior vena cava size/respiratory variation—right atrial

pressure normal.

• Normal inferior vena cava size/reduced variation—right atrial pressure

mildly increased (10mmHg).

• Dilated inferior vena cava size/reduced variation—right atrial pressure

moderately increased (15mmHg).

• Dilated inferior vena cava/absent variation/dilated hepatic veins—right

atrial pressure severely increased (20mmHg).

Other

• Prominent Eustachian valve, Chiari network.

ATRIAL SIZE

661

Atrial size (Table 12.5)

Table 12.5 Parameters to assess left and right atria

Women

Normal

Mild

Moderate Severe

Atrial dimension

LA diameter, cm

2.7-3.8

3.9-4.2

4.3-4.6

>4.6

LA diameter, BSA, cm/m2

1.5-2.3

2.4-2.6

2.7-2.9

>2.9

RA minor axis, cm

2.9-4.5

4.6-4.9

5.0-5.4

>5.4

RA minor axis/BSA, cm/m2

1.7-2.5

2.6-2.8

2.9-3.1

>3.1

Atrial area

LA area, cm2

<20

20-30

31-40

>40

Atrial volume

LA vol, mL

22-52

53-62

63-72

>72

*LA vol/BSA, mL/m2

<29

29-33

34-39

>39

Men

Normal

Mild

Moderate Severe

Atrial dimension

LA diameter, cm

3.0-4.8

4.1-4.6

4.7-5.2

>5.2

LA diameter, BSA, cm/m2

1.5-2.3

2.4-2.6

2.7-2.9

>2.9

RA minor axis, cm

2.9-4.5

4.6-4.9

5.0-5.4

>5.4

RA minor axis/BSA, cm/m2

1.7-2.5

2.6-2.8

2.9-3.1

>3.1

Atrial area

LA area, cm2

<20

20-30

31-40

>40

Atrial volume

LA vol, mL

18-58

59-68

69-78

>78

*LA vol/BSA, mL/m2

<29

29-33

34-39

>39

BSA, Body surface area. *Bold rows identify best validated measures.

662

CHAPTER 12 Reporting and normal ranges

Aortic valve

Descriptive terms

Structure

• Normal, degenerative, rheumatic.

• Bicuspid, fused (RCC-LCC/RCC-NCC/NCC-LCC).

• Unicuspid, quadricuspid.

Leaflet thickness

• Focal thickening (RCC/LCC/NCC), diffuse thickening.

• Severity (mild/moderate/severe).

Calcification

• Present (mild/moderate/severe).

• Focal calcification (RCC/LCC/NCC).

• Diffuse calcification.

Leaflet mobility

• Normal, reduced (mild/moderate/severe), doming.

Other

• Leaflet perforation (RCC/LCC/NCC).

• Leaflet prolapse/flail (RCC/LCC/NCC).

Vegetation

• Location (RCC/LCC/NCC).

• Mobility (non-mobile/mobile), pedunculated.

• Size (small/moderate/large) + dimensions.

Abscess

• Location (RCC-annulus/LCC-annulus/NCC-annulus).

• Size (small/moderate/large) + dimensions.

Mass

• Location (RCC/LCC/NCC), description (see b p.530).

Aortic stenosis (Table 12.6)

• None, present (mild/moderate/severe).

• Quantification:

• Peak and mean transaortic velocity/gradient.

• Aortic valve area.

Aortic regurgitation (Table 12.7)

• None, present (trace, mild, moderate, severe).

AORTIC REGURGITATION

663

Table 12.6 Parameters to assess severity of aortic stenosis

Mild

Moderate

Severe

Peak velocity (m/s)

2.5-2.9

3.0-4.0

>4.0

Peak gradient (mmHg)

<35

35-65

>65

Mean gradient (mmHg)

<20

20-40

>40

Valve area (cm2)

>1.5

1.0-1.5

<1.0

Table 12.7 Parameters to determine severity of aortic regurgitation

Specific signs of severity

Mild

Severe

Vena contracta

<0.3cm

>0.6cm

Jet (Nyquist

Central, <25% of LVOT Central, >65% of LVOT

50-60cm/s)

Descending aorta

No or brief early

diastolic flow reversal

Supportive signs of severity

Mild

Severe

Pressure half time

>500ms

<200ms

Descending aorta

Holodiastolic flow reversal

Left ventricle (only for Normal LV

Moderate or greater LV

chronic lesions)

enlargement (no other cause)

Report as moderate if signs of regurgitation are greater than mild but there are no features of

severe regurgitation.

664

CHAPTER 12 Reporting and normal ranges

Mitral valve

Descriptive terms

Structure

• Normal, rheumatic, myxomatous, degenerative.

Annulus

• Normal, dilated, calcified (mild/moderate/severe).

Leaflet thickness

• Normal, thickened (mild/moderate/severe).

• Leaflet tips, Leaflet body (aMVL/pMVL).

Commissures

• Antero-lateral fusion, posteromedial fusion.

Calcification

• Focal calcification (aMVL/pMVL), diffuse calcification.

• Commissural calcification (anterolateral/posteromedial).

Cleft

• Anterior leaflet, posterior leaflet.

Chordal disease

• Shortening, fusion/thickening, elongation.

• Rupture, calcification.

Papillary muscle

• Rupture, partial rupture (anterolateral/posteromedial).

• Calcification/fibrosis (anterolateral/posteromedial).

Leaflet mobility

• Normal, reduced (mild/moderate/severe).

• Doming, prolapse, bowing.

• Systolic anterior motion (mild/moderate/severe—based on outflow

tract gradient).

• Chordal systolic anterior motion.

Prolapse

• Anterior, posterior leaflet (mild/mod/severe/flail).

• A1, A2, A3, P1, P2, P3 (mild/mod/severe/flail).

Vegetation

• Location (aMVL/pMVL).

• Mobility (non-mobile/mobile), pedunculated.

• Size (small/moderate/large), dimensions.

Abscess

• Location (aorto-mitral/pMVL/annulus).

• Size (small/moderate/large), dimensions.

Mass

Location (aMVL/pMVL), description (see b p.530).

666

CHAPTER 12 Reporting and normal ranges

Mitral stenosis (Table 12.8)

• None, present (mild/moderate/severe).

• Quantitative measurements:

• Peak and mean transmitral velocity/gradient.

• Pressure half-time, mitral valve area.

• Suitable for commissurotomy.

Mitral regurgitation (Table 12.9)

• None, present (trace, mild, moderate, severe).

• Jet direction:

• Anteriorly-, posteriorly-, centrally-directed.

• Wall-impinging jet, directed down pulmonary veins.

• Diastolic mitral regurgitation (present/absent).

• Quantitative measurements:

• MR: LA area ratio, regurgitant volume.

• Vena contracta width, EROA.

• Pulmonary venous flow (normal, blunted systolic flow, systolic flow

reversal).

MITRAL REGURGITATION

667

Table 12.8 Parameters to determine severity of mitral stenosis

Mild

Moderate

Severe

MV area (cm2)

2.2-1.5

1.5-1.0

<1.0

MV pressure half-time (ms)

100-150 150-220

>220

Mean pressure gradient (mmHg)

Variable

>10

TR velocity (m/s)

<2.7

Variable

PA pressure (mmHg)

<30

Variable

>50

Table 12.9 Parameters to assess severity of mitral regurgitation

Specific signs of severity

Mild

Severe

Jet (Nyquist

<4cm2 or <20% left

>40% left atrium

50-60cm/s)

atrium

Small & central

Large & central or wall

impinging and swirling

Vena contracta

<0.3cm

>0.7cm

PISA r (Nyquist

None/minimal

Large (>1cm)

40cm/s)

(<0.4cm)

Pulmonary vein flow

Systolic reversal

Valve structure

Flail or rupture

Supportive signs of severity

Mild

Severe

Pulmonary vein flow

Systolic dominant

Mitral inflow

A-wave dominant

E-wave dominant (>1.2m/s)

CW trace

Soft & parabolic

Dense & triangular

LV and LA

Normal size LV if

Enlarged LV & LA if no

chronic MR

other cause

Report as moderate if signs of regurgitation are greater than mild but there are no features

of severe regurgitation.

668

CHAPTER 12 Reporting and normal ranges

Tricuspid valve

Descriptive terms

Structure

• Normal, rheumatic, myxomatous (redundant).

• Ebstein.

Annulus

• Normal, dilated.

• Calcified.

Leaflet thickness

• Normal, increased.

• Leaflet tips, leaflet body (anterior/posterior/septal).

Calcification

• Focal calcification (anterior/posterior/septal).

• Diffuse calcification.

Papillary muscle

• Rupture.

Leaflet mobility

• Normal, reduced (mild/moderate/severe).

• Doming, prolapse, bowing.

Prolapse

• Anterior leaflet (mild/mod/severe/flail).

• Posterior leaflet (mild/mod/severe/flail).

• Septal leaflet (mild/mod/severe/flail).

Vegetation

• Location (anterior/posterior/septal).

• Mobility (non-mobile/mobile), pedunculated.

• Size (small/moderate/large) + dimensions.

Abscess

• Location (anterior-annulus/posterior-annulus/septal).

• Size (small/moderate/large) + dimensions.

Mass

• Location (anterior/posterior/septal).

• Description (see b p.530).

Tricuspid stenosis

• None, present.

• Quantitative measurements.

• Peak and mean transtricuspid gradient.

• Tricuspid valve area.

Tricuspid regurgitation

• None, present (trace, mild, moderate, severe).

• Jet direction: free wall-directed, septal-directed, centrally-directed.

• Hepatic vein flow:

• Normal, blunted systolic flow.

• Systolic flow reversal.

RIGHT ATRIAL PRESSURE

669

Tricuspid regurgitation (Table 12.10)

Table 12.10 Parameters to assess severity of tricuspid regurgitation

Mild

Severe

Qualitative

Valve structure

Normal

Abnormal

Jet (Nyquist 50-60cm/s)

<5cm2

>10cm2

CW trace

Soft & parabolic Dense & triangular

Semi-quantitative

Vena contracta

>0.7cm

PISA r (Nyquist 40cm/s)

>0.9cm

<0.5cm

Tricuspid inflow

Normal

E wave dominant >1m/s

Hepatic vein flow

Normal

Systolic reversal

Quantitative

EROA

Not defined

>/40mm2

R vol

Not defined

>45mL

RV/RA/IVC

Normal size

Usually dilated

Report as moderate if signs of regurgitation are greater than mild but there are few features

of severe regurgitation.

Right atrial pressure (Table 12.11)

Table 12.11 Assessment of right atrial pressure

RAP (mmHg)

0-5

5-10

10-15 15-20 >20

IVC size (cm)

<1.5

1.5-2.5

1.5-2.5 >2.5

>2.5

Respiratory variation Collapses >50% collapse <50%

<50% No

change

670

CHAPTER 12 Reporting and normal ranges

Pulmonary valve

Descriptive terms

Structure

• Normal, dysplastic, bicuspid.

Mobility

• Normal, reduced.

• Doming.

Vegetation

• Location.

• Mobility (non-mobile/mobile), pedunculated.

• Size (small/moderate/large) + dimensions.

Mass

• Location, description (see b p.530).

Stenosis

• None, present (mild/moderate/severe).

• Location (valvular, infundibular, valvular +infundibular supravalvular,

branch).

• Left or right main pulmonary artery.

• Quantitative measurements: peak and mean transpulmonary gradient.

Regurgitation

• None, present (trace, mild, moderate, severe).

Pulmonary pressure

• Normal.

• Elevated systolic pressure (mild/moderate/severe).

• Elevated diastolic pressure (mild/moderate/severe).

• Estimated pulmonary artery.

Pulmonary artery

Descriptive terms

Appearance

• Normal, abnormal.

Dilatation

• Absent, present (mild/moderate/severe).

Thrombus

• Main/right/left pulmonary artery.

Pulmonary artery stenosis

• Main/right/left pulmonary artery (mild/moderate/severe).

Patent ductus arteriosus

• Absent, present.

PULMONARY STENOSIS

671

Pulmonary regurgitation (Table 12.12)

Table 12.12 Parameters to assess pulmonary regurgitation

Mild

Severe

Pulmonary valve anatomy

Normal

Abnormal

Jet size on colour flow

<10mm long

Large with wide origin

CW density and shape

Soft and slow

Dense and steep

PR index

<0.77

Jet width of RVOT

>65%

PA flow

Increased

Greatly increased

compared to systemic

Right ventricle size

Normal

Dilated

If features suggest more than mild regurgitation but no features of severe grade as moderate.

Pulmonary stenosis (Table 12.13)

Table 12.13 Parameters to determine severity of pulmonary stenosis

Mild

Moderate

Severe

Peak velocity (m/s)

3-4

Peak gradient (mmHg)

<36

36-64

>64

Valve area (cm²)

>1.0

0.5-1.0

<0.5

672

CHAPTER 12 Reporting and normal ranges

Prosthetic valves

Descriptive terms

Type

• Mechanical (tilting disk/bileaflet/ball and cage/other).

• Bioprosthesis (stented xenograft/homograft/stentless.

• Autograft (Ross)/other).

• Manufacturer & size.

• Annuloplasty ring, valve repair.

Sewing ring

• Well seated, rocking, dehisced.

Occluder mechanism

• Normal, thickened leaflets (bioprosthesis).

• Normal mobility, restricted mobility, flail.

Abnormal masses

• Strand(s), micro-cavitations, pannus, thrombus.

• Vegetation (+description), abscess (+description).

• Fistula.

Stenosis

• Present, severity (as for native valve).

Regurgitation

• Physiologic, prosthetic, paraprosthetic.

• Severity (as for native valve).

PROSTHETIC VALVE VELOCITIES

673

Prosthetic valve velocities

Table 12.14 provides a guide to maximal expected velocities for different

valve types. Refer to manufacturer guidelines for definitive measures and

take into account clinical scenario. Velocities depend on left ventricle func-

tion, volume, and ionotropic status. Therefore minimal gradients are not

presented. In individual cases the threshold may be exceeded with a func-

tionally normal prosthesis—in particular if there is a hyperdynamic state.

Table 12.14 Maximum prosthetic velocities

Aortic prosthetic valves:

Bileaflet valve (e.g. St Jude)

Size (mm)

Vmax (m/s)

4.5

3.5

3.1

2.5

Tilting disc (e.g. Medtronic Hall, BS)

Size (mm)

— 21 23

Vmax (m/s)

— 3.7 3.0

2.4

2.1

Ball and cage (e.g. Starr-Edwards)

Vmax (m/s)

3.6

Bioprostheses (e.g. Hancock, Carpentier Edwards)

Size (mm)

Vmax (m/s)

3.5

3.0

2.9

2.5

Mitral prosthetic valves:

Bileaflet valve (e.g. St Jude)

Size (mm)

Vmax (m/s)

4.5

3.5

3.1

2.5

Tilting disc (e.g. Medtronic Hall, BS)

Size (mm)

— 21 23

Vmax (m/s)

— 3.7 3.0

2.4

2.1

Ball and cage (e.g. Starr-Edwards)

Vmax (m/s)

3.6

Bioprostheses (e.g. Hancock, Carpentier Edwards)

Size (mm)

Vmax (m/s)

3.5

3.0

2.9

2.5

674

CHAPTER 12 Reporting and normal ranges

Aorta

Descriptive terms

Appearance

• Normal, abnormal.

Dilatation

• Absent, present (mild/moderate/severe).

• Location and dimensions:

• Dilated atrioventricular annulus.

• Dilated aortic root/sinuses.

• Dilated sinotubular ridge.

• Dilated ascending aorta.

• Dilated transverse aorta.

• Dilated descending thoracic aorta.

• Dilated abdominal aorta.

Aneurysm

• Absent, sinuses of Valsalva (left/right/non-coronary).

• Aortic root, ascending aorta, transverse aorta.

• Descending thoracic aorta, abdominal aorta.

• Dimensions, type (fusiform, saccular).

• Ruptured sinus of Valsalva (to right atrium, right ventricle, left atrium,

left ventricle).

Atheroma/thrombus

• Absent, present.

• Location (aortic root, ascending aorta, transverse aorta, descending

thoracic aorta, abdominal aorta).

• Appearance (layered/mural, protruding, ulcer).

• Severity (mild/moderate/severe).

• Mobility (immobile/mobile).

• Graft (prosthetic/homograft) + location.

Dissection

• Location, entry point, exit point(s).

• False lumen thrombus (absent/partial/present).

• Stanford type A or B.

• Intramural haematoma and location.

• Transection and location.

Coarctation

• Absent, repaired/residual, present.

• Severity (mild/moderate/severe).

• Measurements (minimum diameter, gradient).

676

CHAPTER 12 Reporting and normal ranges

Masses

Descriptive terms

Thrombus

• Absent, present.

• Size (small/moderate/large).

• Location.

• Description:

• Shape (flat or mural/protruding/spherical/other).

• Surface (regular/irregular).

• Texture (layered/solid/part solid/calcified).

• Mobility (mobile/fixed).

• Dimensions.

Tumour

• Absent, present.

• Size (small/moderate/large).

• Location.

• Description:

• Shape (flat or mural/pedunculated/papillary/spherical/other).

• Surface (regular/irregular/multilobular/other).

• Texture (solid/layered/cystic/calcified/heterogeneous).

• Mobility (mobile/fixed).

• Dimensions.

• Type (suggestive of myxoma/fibroelastoma/etc.).

678

CHAPTER 12 Reporting and normal ranges

Pericardium

Descriptive terms

Appearance

• Normal, abnormal.

Effusion

• Absent, present.

• Size (small/moderate/large).

• Location:

• Circumferential.

• Localized (near . . . left ventricle, right ventricle, left atrium, right

atrium).

• Appearance/content (clear fluid, fibrinous, focal strands/masses,

effusive-constrictive.

Thickening/calcification

• Absent, present.

Mass

• Absent, present.

Haemodynamic effects

• Septal bounce.

• Chamber collapse (absent/present + chamber).

• Increased respiratory variation (absent, present + location).

• Compatible with tamponade or constrictive.

Pericardial fluid (Table 12.15)

Table 12.15 Assessment of pericardial effusion based on thickness and

volume

Trace

Mild

Moderate

Severe

Thickness (cm)

<0.5

0.5-1

1-2

Volume (mL)

50-100

100-250

250-500

>500

679

Index

false lumen 318, 522, 525

planimetry 454

hypotension 537

pulmonary

A’ 248

Stanford classification 318

hypertension 138

abdominal aorta 308, 310

surgery 524

septal hypertrophy 138

abdominal aorta view 90-1

TOE 522-3

subaortic

abdominal aortic

true lumen 522, 525

membrane 110

aneurysm 324-5

TTE 318-19

3D assessment 138-9

abnormal relaxation 246,

aortic regurgitation

TOE 454

249, 251

acute/chronic 150

TTE 134-5

abscess 188-9, 472-3

age 142

valve area 50

accreditation 584, 631

aortic stenosis 138

aortic transection 526

AcuNav® 549, 551

causes 143

aortic valve

acute

colour M-mode 148-9,

anatomy 132

echocardiography 628

456

bicuspid 134, 138, 152-3,

cardiopulmonary

deceleration slope 146

460

resuscitation 631-2

descending aorta

five cusps 152

diagnostic 634

flow 144, 147, 458-9

mitral valve repair 447

FEEL algorithm 632-3

grading severity 144-5,

normal TOE

safety issues 630

147, 456-8, 663

findings 452-3

acute pericarditis 306

holodiastolic aortic flow

normal TTE findings

acute ventricle 646

reversal 144, 147,

132-3

adenosine protocol 618-19

458-9

preoperative assessment

agitated saline 562, 566-7,

jet area 148

using TOE 460

570

jet length 148-9

quadricuspid 152-3

akinetic left ventricle

jet width 144

reporting 662

segments 597

left ventricle 146

vti and passive leg

ALARA principle 54

PISA 150

raising 640

aliasing 28-30

pressure half-time 146-7,

aortic valve and root

allergic reaction

150

view 552-3

management 571

regurgitant volume 150

aortic valve replacement,

A-mode 8-9

3D assessment 148, 456

postoperative

analgesia, TOE 358

TOE 456

assessment 462-3

anomalous pulmonary

TTE 142-3

aortic views 400-1

drainage 671

vena contracta 144-5,

apex forming 264

antibiotic prophylaxis,

148

apex remodelling 534

TOE 349

aortic remodelling 460

apical five chamber

aorta

aortic root 310

view 80-1, 102

anatomy 308

aortic root dilatation 143,

apical four chamber

emergency evaluation 514

310-11

view 78-9, 100-1

isthmus 309

aortic root

apical three chamber

normal TOE

replacement 314

view 84-5, 103

findings 514-15

aortic sclerosis 134

apical 3D views 86-7

normal TTE findings

aortic size 310-11, 675

apical two chamber

308-9

aortic stenosis

view 82-3, 103

reporting 674

aortic regurgitation 138

apical window 60-3

traumatic injury 526

dobutamine stress

area length equation 200-1,

aortic annulus 310

echo 140-1

212, 280, 478

aortic arch 308, 514, 516

effective orifice area/valve

artefacts

aortic atherosclerosis

area 136-7

beam-width 318

324-5, 520-1

grading severity 134-6,

drop out 38

aortic coarctation 320-1,

137, 454-5, 663

reverberation 16-17, 32,

528

hypotension 537

318

aortic dilatation 314-15

left ventricle 138, 140-1

stitch 38-9

aortic dissection

mean pressure

ascending aorta 308

differentiating intimal flaps

gradient 136

atrial chamber

from artefacts 522, 525

peak pressure

arrangement 334

dissection flap 318-19,

gradient 136

atrial septal aneurysm

522, 525

peak velocity 134, 137

290-1

680

INDEX

atrial septal defects

cardiovascular magnetic

lactation 571

ICE 556, 557-8, 559

resonance 588

left-sided contrast

TOE 502-3, 505

CARPA reactions 570

agents 562, 564-5, 570

TTE 288-9

Carpentier

left ventricular

atrial septal view 552-3

classification 424

opacification 576,

atrial septum

catheter ablation of

577-8, 579

anatomy 286

arrhythmias 560

low mechanical index

normal TOE

catheter occlusion of left

imaging 576

findings 500-1

atrial appendage 560

myocardial

normal TTE findings

central venous line 546

perfusion 582-3, 585

286-7

Chiari network 284, 498-9

patent foramen

reporting 661

christa terminalis 498

ovale 572-3

atrial septum (bicaval)

circumferential strain 44-5,

persistent left superior

view 380-1

239, 241

vena cava 574

attenuation 14-15, 38

cleft mitral valve leaflet 289

pregnancy 571

audit 623

closing jets 178, 448

pulmonary shunts 574

autografts 180

coaption 132

right-sided contrast

auto-regulation 594

coarctation of the

agents 562, 566-7, 570

AV delay 260-1

aorta 320-1, 528

right-sided contrast

axial resolution 20

colour flow mapping

studies 572-3, 575

30-1, 96

safety issues 54, 570-1

colour inversion 30

second harmonics 48, 576

commissures 132

shunts 502, 506-7, 562,

ball and cage valves 176-7,

complete atrio-ventricular

572, 574

179, 463, 672

canal defect 289

training 584

BART principle 30-1

compress 18, 42

tricuspid

beam-width artefact 318

concentric left ventricular

regurgitation 574-5

benign cardiac

hypertrophy 218

CoreValve® 465

tumours 326-7

concentric remodelling 140,

coronary artery disease,

Bernoulli equation 52-3

218

stress echo 590-1

Beutel display 269

congenital heart

coronary artery supply to

bicuspid valves 134, 138,

disease 330-1, 333,

ventricles 235, 481

152-3, 460

335-6

coronary artery surgery,

bicycle protocol 612-13

surgical correction 340-1

TOE 532

bileaflet valves 177-9, 672

congenital pericardial

coronary sinus 498

bioprosthetic valves 180-2,

disease 306

coronary sinus

672

constrictive

defect 504

biphasic response 596

pericarditis 302-3, 305

coronary sinus

biplane imaging 64

continuity equation 50-1

view 386-7

Blalock-Taussig shunt 340

continuous wave

corrected aortic flow

blunted systolic pulmonary

Doppler 26-7

time 644

vein flow 120

contractile reserve 596, 616

cor triatum 278

B-mode 8-9

critical illness

contrast echocardiography

body surface area 636

561

advanced haemodynamics

bowing 128-9

accreditation 584

642-3

Bruce protocol 612-13

acute coronary

fluid responsiveness

syndromes 570

640-1

administration of contrast

volume status 636-9

agents 568-9

weaning from

carcinoid syndrome 166

adverse events 570

ventilator 646-7

cardiac computed

agitated saline 562, 566-7,

cropping 40-1

tomography 588

570

cardiac index 230

allergic reaction

cardiac output 230, 642-3

management 571

cardiac tamponade

bolus injection 568-9

de-airing 447, 462

TOE 512

contrast infusion 568-9

deceleration slope 146

TTE 300-1

dobutamine stress

deceleration time 246

cardiac tumours 326-7, 329

echo 580-1

deep transgastric

cardiac twisting 44

Doppler enhancement

view 396-7

cardiopulmonary

574-5, 578

depth compensation 14, 18

bypass 532-3

gas microspheres 48, 562

descending aorta 308

cardiopulmonary

intermittent imaging 576

descending aortic flow 144,

resuscitation 631-2

intravenous injection 568

147, 458-9

INDEX

681

descending thoracic

Ebstein’s anomaly 166, 337

aorta 308, 310, 514,

eccentric left ventricular

516, 518

hypertrophy 218

gain 18-19

diastolic function 246-7,

echoes 12

gas microspheres 48, 562

249-50

Edwards Sapien® 465

Gerbode defects 294

diastolic tail 320-1

E/E’ 248, 252

Glenn shunt 340

DICOM 66

effective orifice area 136-7

global strain 238

digital image storage 66

prosthetic valves 184

global systolic function

dilated cardiomyopathy 222

effective regurgitant orifice

228-9, 231, 233, 480

dipyridamole

area 126

glutaraldehyde 354

protocol 618-19

ejection fraction 228-9,

governance 590

dissection flap 318-19,

266, 274

grey scale 18

522, 525

elbowing appearance 110

dobutamine stress echo

electrophysiology,

aortic stenosis 140-1

ICE 560

atropine use 614

ellipsoid formula 212, 280

haemodynamic

beta-blockers 614

endocardial cushion

instability 536-7

compared to exercise 612

defect 289

harmonic imaging 22-3,

contrast echo 580-1

endocarditis

48, 576

myocardial

reporting 677

harmonics 22

ischaemia 614-15

TOE 472-3

heart failure with normal

myocardial viability 616-17

TTE 166-7, 188-9

ejection fraction

preoperative assessment

Eustachian valve 284,

(HFNEF) 252-3

for non-cardiac

498-9

high pulse repetition

surgery 600-1

exercise stress

frequency pulsed wave

wall thickening 597

protocols 612-13

Doppler 29

Doppler echocardiography

excursion 132

hockey stick

aortic stenosis 454

extra-cardiac tumours 328,

appearance 110

cardiac tamponade 300-1

333

holodiastolic aortic flow

constrictive

reversal 144, 147, 458-9

pericarditis 304-5

homografts 180

continuous wave

hypertrophic

Doppler 26-7

failure to wean off

cardiomyopathy 220-1,

contrast studies 574-5,

bypass 533

225, 590

578

false lumen 318, 522, 525

hypoplastic left

global systolic

FEEL algorithm 632-3

ventricle 338

function 230-1, 233

fentanyl 358

hypotension 536-7

high pulse repetition

fibrin strands 182, 298-9

hypovolaemic

frequency pulsed wave

fibroelastoma 326-7, 530-1

hypotension 536-7

Doppler 29

fibroma 326

hypoxaemia 536, 538

image quality 96

fibrous pericardium 296

pulsed wave Doppler

fistula 188, 472

28-9

five chamber view 370-1

shunt quantification 288,

five cusps 152

idiopathic dilated

502

flail leaflets 129-31

cardiomyopathy 222

theory behind 24-5

flow convergence

image resolution 20-1

3D colour Doppler 36-7

zone 126-7

infective endocarditis, see

tissue Doppler, see tissue

fluid dynamics 50-1, 53

endocarditis

Doppler imaging

fluid responsiveness 640-1

inferior sinus venosus

Doppler effect 24-5

fluid status 636-7

defect 504

Doppler frequency 26

focusing 20

inferior vena cava

Doppler shift 24, 26

Fontan procedure 340

fluid responsiveness

Dor procedure 534

foramen ovale 286

640-1

double outlet right

foreshortening 200

volume status 636, 639

ventricle 338

fossa ovalis 286

inferior vena cava

dP/dt 232-3

four chamber view 368-9

view 90-1

drop out artefacts 38

fractional area change

information for patients 56,

dynamic range 18-19

228-9, 274-5

350, 604

fractional shortening 228-9,

inlet septum 292

488

intensive care units,

‘front door’

TOE 345

E’ 248

echocardiography 628

interatrial septum, see atrial

E/A ratio 246

fundamental frequency 22

septum

682

INDEX

interventricular

left ventricular function

dyssynchrony 254-5

diastolic function 246-7,

interventricular septum, see

jet area 118-19, 148,

249-50

ventricular septum

158, 422

global systolic

intima-media thickness 520

jet length 148-9

function 228-9, 231,

intra-aortic balloon

jet width 144

233, 480

pump 540-1

mitral valve repair 447

intracardiac

mitral valve

echocardiography (ICE)

replacement 450

aortic valve and root

Lambl’s excresences 152

normal ranges 654-5

view 552-3

Langranian strain 46

regional systolic

atrial septal

lateral resolution 20

function 234-7, 480

interventions 556,

left atrial appendage

TOE 480-1

557-8, 559

catheter ablation 560

TTE 226-7

atrial septal view 552-3

ICE 554

left ventricular hypertrophy

catheter ablation of

TOE 492-3

aortic stenosis 140

arrhythmias 560

left atrial function 282

physiological 218

catheter occlusion of left

left atrial occluder 546

TTE 218-19

atrial appendage 560

left atrial pressure 642

left ventricular mass

catheter preparation 550

left atrial size

normal ranges 216, 482-3,

commercially available

normal ranges 283, 660

654-5

catheters 549

TOE 490-1

TOE 478

electrophysiological

TTE 248, 280-1

TTE 210-11, 213, 215

interventions 560

left atrium

left ventricular non-

fluoroscopy

anatomy 278

compaction 222-3

screening 550-1

normal TOE findings 490

left ventricular

imaging planes 552-3, 555

normal TTE findings

opacification 576,

indications 548

278-9

577-8, 579

left atrial appendage 554

reporting 659

left ventricular outflow

left ventricle view 554-5

spontaneous

tract 132

mechanical catheters 550

contrast 493

obstruction 220, 448

mitral valve view 554-5

left lower pulmonary vein

vti 232

patient preparation 550

view 384-5

left ventricular size

phased-array

left upper pulmonary vein

area length equation

catheters 550

view 384-5

200-1, 478

pulmonary vein view

left ventricle

foreshortening 200

554-5

anatomy 192

linear measures 196-7,

radiological

aortic regurgitation 146

478

interventions 560

aortic stenosis 138,

normal ranges 198, 206,

right ventricle view 554-5

140-1

208, 482-3, 654-5

standard view 552-3

assessment 194

Simpson’s method 198-9,

TAVI 560

concentric

478

transducers 6-7, 549-50

remodelling 140, 218

3D volumetric

transseptal puncture

fluid responsiveness

measures 196, 202-3,

guidance 560

640-1

205-6, 207

vascular access 550-1

hypoplastic 338

TOE 478-9

intracardiac shunt 538

normal TOE

TTE 196, 208

intramural haematoma 526

findings 476-7

2D volumetric

intraoperative TOE 345,

normal TTE findings

measures 196,

438

192-3

198-201, 478

intrapulmonary shunt 538

reporting 652

left ventricular strain 238

intravascular probes 6, 21

volume status 638-9

advantages and

intravenous drug users 166

left ventricle view 554-5

disadvantages of strain

intraventricular

left ventricular assist

imaging 240

dyssynchrony 254-5

devices 540

normal values 239

intubation 362-3

left ventricular ejection

speckle tracking 238,

iRotate imaging 64, 608

fraction 228-9

242-4, 245

ischaemic cascade 594-5

left ventricular end-diastolic

left ventricular

ischaemic mitral

pressure 644

synchrony 254-7, 258-9

regurgitation 534

left ventricular fractional

left ventricular thickness

isovolumetric relaxation

area change 228-9

normal ranges 216

time 246

left ventricular fractional

TTE 210-11, 213, 215

isthmus 309

shortening 228-9

lipoma 326, 530

INDEX

683

lipomatous interatrial

TTE 116

modes 8-9

hypertrophy 530

vena contracta 120, 422

multiplane image

local anaesthetic, TOE 358

mitral stenosis

acquisition 64-5

long axis (aortic valve)

differentiating rheumatic

myocardial ischaemia

view 376-7

stenosis from

adenosine protocol

long axis (mitral valve)

calcification 110

618-19

elbowing appearance 110

detection using stress

longitudinal strain 44-5,

grading severity 112-13,

echo 594-5

239

114-15, 432-3, 435, 666

dipyridamole

lossless image

hockey stick

protocol 618-19

compression 67

appearance 110

dobutamine stress

lossy image compression 67

new stenosis

echo 614-15

Luminity® 566

postoperative 446

hypotension 536-7

lungs 544

percutaneous valvotomy

Myocardial Performance

suitability

Index (MPI) 272-3

assessment 444-5

myocardial perfusion

planimetry 112-13, 434-5

contrast echo 582-3, 585

malignant cardiac

preoperative assessment

stress echo 598-9

tumours 326-7

using TOE 438

myocardial scintigraphy 588

Marfan syndrome 316-17

pressure gradient 114-15,

myocardial viability, stress

432

echo 596, 616-17

masses 326-7, 329, 530-1,

676

pressure half-time

myocarditis 224

matrix array transducers

114-15, 432-3

myxoma 326-7, 530

4-5

3D assessment 112-13,

mechanical cardiac

434-5

support 540-1

TOE 432

mechanical index 18, 54

TTE 110-11

natural strain 46

mechanical prosthetic

mitral valve

nodule of Arantius 132

valves 176-7

anatomy 106

non-cardiac surgery,

metastases 328

identifying leaflets and

preoperative stress

midazolam 358

segments 418

echo 600-1

MitraClip® 440-1, 443

normal TOE

Nyquist limit 28

mitral regurgitation

findings 418-19

Carpentier

normal TTE findings

classification 424

106-7, 109

continuous wave Doppler

postoperative assessment

oblique sinus 296, 510

intensity/shape 122

of repair 446

obstructive congenital

effective regurgitant

postoperative systolic

disorders 673

orifice area 126

anterior motion 439,

oesophageal varices 348

grading severity 118,

446

off-pump coronary artery

119-20, 121, 123, 422,

preoperative assessment

bypass 534

423-5, 666

using TOE 436-8, 439

optimization 260-1

intraoperative TOE 438

reporting 664

Optison® 564

ischaemic 534

suitability for repair 130

outlet septum 292

jet area 118-19, 422

mitral valve balloon

mild/trivial 117

valvotomy, TOE

MitraClip® 440-1, 443

assessment for

mitral inflow 122-3

suitability 444-5

physiological 116-17

mitral valve inflow 246-7,

pacing stress 620

PISA 126-7

249, 251

pacing wires 546

postoperative residual

mitral valve prolapse

pannus 182

regurgitation 446

bowing 128-9

papillary

preoperative assessment

flail leaflets 129-31

fibroelastoma 326-7

using TOE 436

3D assessment 128-9,

parasternal long axis

pulmonary venous

428, 429-30, 431

view 68-9, 97

flow 120-1, 422-3

TOE 426-7

parasternal right ventricle

regurgitant flow 126

TTE 128

inflow view 70-1

regurgitant fraction 122

mitral valve replacement,

parasternal right ventricle

regurgitant jet

postoperative

outflow view 70-1

appearance 116-17

assessment 448-9, 451

parasternal short axis

regurgitant volume 122

mitral valve view 554-5

(aortic) view 72-3, 99

3D assessment 124-5

M-mode 8-10

parasternal short axis

TOE 420-1

moderator band 262

(mitral) view 74-5, 98

684

INDEX

parasternal short axis

post processing 40-1

pulmonary artery diastolic

(ventricle) view

power mode (amplitude)

pressure 172

74-5, 98

imaging 48

pulmonary artery systolic

parasternal 3D views 76-7

pregnancy

pressure 162

parasternal window 60-3

aortic dilatation 314

pulmonary artery

paravalvular

contrast echo 571

view 398-9

regurgitation 186-7

pressure gradient 26,

pulmonary embolism 538

partial atrio-ventricular

114-15, 184, 432

pulmonary hypertension,

canal defect 289

pressure half-time 114-15,

aortic stenosis

passive leg raising 640

146-7, 150, 432-3

grading 138

patent ductus

pressure overload 276-7

pulmonary regurgitation

arteriosus 336

primum atrial septal

grading severity 172-3,

patent foramen ovale 286,

defect 288-9, 504

670

290, 502, 538, 572-3

probes

TOE 470-1

patient information 56,

frequency and

TTE 170-1, 173

350, 604

resolution 20-1

pulmonary regurgitation

peak systolic right

intracardiac 6-7, 549-50

index 172

ventricular basal free

intravascular 6, 21

pulmonary shunts 562, 574

wall TDI 274

transoesophageal

pulmonary stenosis

peak systolic strain 32

6-7, 21

grading severity 174-5, 670

peak systolic strain rate 32

transthoracic 4-5, 21

TOE 470-1

pectinate muscle 493

prolate ellipse of

TTE 174

penetrating aortic ulcer 526

revolution 210

pulmonary valve

perfusion imaging

prosthetic valves

anatomy 168

contrast echo 582-3, 585

degeneration 182

normal TOE findings 470

stress echo 598-9

dehiscence 182-3

normal TTE findings 168-9

pericardial cysts 306, 328

fibrin strands 182

reporting 669

pericardial effusion

orifice area 184

pulmonary veins, TOE 384,

thickness and volume 673

pannus 182

494-5

TOE 512-13

physiological

pulmonary vein view 384-5,

TTE 298-9

regurgitation 178

554-5

pericardial space 296, 510

postoperative

pulmonary venous

pericardial surfaces 296,

assessment 448-9,

flow 120-1, 248, 251,

510

451, 462-3

422-3

pericardial thickness 296

pressure gradients 184

pulmonary wedge

pericardial tumours 306

prolapse 182

pressure 644

pericardiocentesis 306-7

pseudo-microbubbles 182-3

pulsed wave Doppler 28-9

pericarditis

regurgitation 142, 186-7,

pulse repetition

acute 306

448, 462

frequency 28

constrictive 302-3, 305

reporting 671

pulsus paradoxus 301

pericardium

rocking valve 182-3

anatomy 296

stenosis 184

congenital disease 306

structural damage 182

reporting 673

sutures 182

Qp/Qs 288

TOE 510-11

thrombus 182

quadricuspid valves 152-3

TTE 296-7

TOE 177

quality control 623

persistent left superior vena

TTE 176-80, 181

cava 574, 671

vegetations 182

persistent truncus

velocities 184, 672

arteriosus 338

proximal aorta 310, 516,

pethidine 358

518

radial strain 44-5, 239

phased-array catheters 550

proximal ascending

reflection 12-14

piezoelectric crystals 4

aorta 308, 310, 514

refraction 12-13

PISA 126-7, 150

proximal isovelocity surface

regional strain 240

planimetry 112-13, 434-5,

area (PISA) 126-7, 150

regional systolic

454

pseudo-microbubbles

function 234-7, 480

pleural effusions 544-5

182-3

regurgitant flow 126

pleural fluid 296, 512

pseudonormal filling 246,

regurgitant fraction 122

pleural space 544

249, 251

regurgitant volume 122,

positron emission

pulmonary arterial occlusion

150

tomography 588

pressure 644

relative wall thickness 218

posterior wall

pulmonary artery,

reporting, standard

thickness 210-11

reporting 669

approach 650-1

INDEX

685

restrictive

TOE 488

situs inversus 334-5

cardiomyopathy 222,

TTE 272-3, 275

situs solitus 334-5

303

right ventricular outflow

slice modes 40-1

restrictive filling 246,

tract 264

SonoVue® 564-5, 570

249, 251

right ventricular

SoundStar™3D 549

reverberation artefacts

overload 276-7

sound waves 2-3

16-17, 32, 318

right ventricular size

spatial resolution 20

reversed systolic pulmonary

normal ranges 489, 657

speckle pattern 44

vein flow 120

TOE 486-7

speckle tracking

rhabdomyoma 326

TTE 264-5, 267, 269

echocardiography

right atrial pressure 162-3,

right ventricular systolic

44-5, 46-7, 238,

636-7, 668

pressures 162-3

242-4, 245

right atrial size

right ventricular wall

specular echoes 12

normal ranges 283, 660

thickness 270-1, 486

specular reflection 12

TOE 496

Ritter method 260

stand-alone probes 4-5

TTE 284-5

rocking valve 182-3

Stanford classification 318

right atrium

Ross procedure 180

stented bioprostheses 177,

anatomy 284

180-1, 463

normal TOE

stentless bioprostheses 180

findings 496-7

stitch artefacts 38-9

normal TTE findings

S’ 274

strain 32, 238

284-5

safety issues

advantages and

reporting 659

acute echo 630

disadvantages of strain

volume status 636, 639

contrast echo 54, 570-1

imaging 240

right heart

stress echo 605

circumferential 44-5, 239,

haemodynamics 162-3

ultrasound 54

241

right lower pulmonary vein

scattering 12-13

global 238

view 384-5

screenwiper principle

Langranian 46

right parasternal view 94-5

364-6

longitudinal 44-5, 239

right parasternal

second harmonic

natural 46

window 60-1

imaging 22-3, 48, 576

normal values 239

right-to-left shunts 538,

secundum atrial septal

radial 44-5, 239

540, 562

defect 288

regional 240

right upper pulmonary vein

device closure 504-5

speckle tracking 44-6, 47,

view 384-5

sedation, TOE 358-60

238, 242-4, 245

right ventricle

segment models 234, 237

strain rate 32

anatomy 262

sepsis, hypotension 536-7

stress echocardiography

double outlet 338

septal hypertrophy 138

587

normal TOE

serous membranes 296

adenosine protocol

findings 484-5

sheathed probes 354

618-19

normal TTE findings

short axis (aortic valve)

analysis 622

262-3

view 372-3

aortic stenosis 140-1

reporting 656

short axis (right ventricle)

audit 623

volume status 638-9

view 374-5

bicycle protocol 612-13

right ventricle inflow-

shunts

Bruce protocol 612-13

outflow view 374-5

contrast echo 502, 506-7,

contraindications 592

right ventricle view 554-5

562, 572, 574

contrast echo 580-1

right ventricular cavity

hypoxaemia 538

dipyridamole

size 264, 486

left ventricular assist

protocol 618-19

right ventricular

devices 540

dobutamine stress, see

contouring 268-9

quantification 288, 502

dobutamine stress

right ventricular ejection

surgical correction of

echo

fraction 266, 274

congenital heart

drugs 602

right ventricular end-

defects 340

equipment 602

diastolic volume 266

Simpson’s biplane

exercise stress

right ventricular end-systolic

method 198-9, 212, 478

protocols 612-13

volume 266

single ventricle 337-8

hypertrophic

right ventricular fractional

sinotubular junction 132

cardiomyopathy 590

area change 274-5

sinus of Valsalva 132,

image acquisition 608

right ventricular fractional

310-11, 313, 517

indications 590-1

shortening 488

sinus of Valsalva

information for

right ventricular function

aneurysm 322-3, 528

patients 605

normal ranges 657

sinus venosus defect 288, 504

iRotate 608

686

INDEX

stress echocardiography

tetralogy of Fallot 673

stress echo 608, 623

(Cont.)

Thebesian valve 498

3D vision 42

known coronary artery

thermal index 54

thresholding 42

disease 590

thoracic aortic

transducers 4-5

monitoring 610

aneurysm 324, 528

tricuspid

myocardial

3D echocardiography 34

regurgitation 160-1

ischaemia 594-5,

aorta view 406

tricuspid stenosis 164

614-15

aortic regurgitation 148, 456

tricuspid valve view 408-9

myocardial

aortic stenosis 138-9

windows 62-3

perfusion 598-9

aortic valve views 406-7

3D-mode 8-9

myocardial viability 596,

apical views 86-7

thrombus 326, 493, 530-1,

616-17

applications 36

538

pacing stress 620

artefacts 38-9

prosthetic valves 182

patient preparation 604

atrial septum view 412-13

tilting disc valves 176-7,

personnel 602

balloon valvotomy 445

463, 672

preoperative assessment

cardiomyopathies 225

time-gain compensation

for non-cardiac

colour Doppler 36-7

14, 18

surgery 600-1

colour maps 42

tissue Doppler imaging 32-3

pre-test probability of

cropping 40-1

diastolic function 248, 251

coronary artery

full volume 3D data

left ventricular

disease 589

sets 34-5

synchrony 256-7

quality control 623

gain adjustment 42-3

stress echo 623

safety issues 605

global systolic

trabecular septum 292

sample report 624-5

function 230

training 584, 623, 631

set-up 606-7

image acquisition 62-3

transcatheter aortic

subaortic muscular

image display 40-1

valve implantation

obstruction 590

image optimization 62

(TAVI) 464-7, 560

suspected coronary artery

image quality 96

transducers

disease 590-1

image rendering 42

frequency and

target heart rates 611

left ventricle view 410-11

resolution 20-1

termination criteria 610,

left ventricular

intracardiac 6-7, 549-50

614

dyssynchrony 258

intravascular 6, 21

3D imaging 608, 623

left ventricular mass

transoesophageal 6-7, 21

tissue Doppler 623

214-15

transthoracic 4-5, 21

training 623

left ventricular size 196,

transgastric long axis

treadmill protocol 612-13

202-3, 205-6, 207

(aortic) view 392-3

valvular heart disease 590

limitations 36

transgastric long axis

vasodilator stress 618-19

live images 34

view 390-1

views 606-7

live 3D 36-7

transgastric right ventricle

stroke volume 230-1,

live 3D zoom 36

view 394-5

642-3

magnification 42

transgastric short axis

subaortic membrane 138

mitral regurgitation 124-5

view 388-9

subcostal views 88-9, 104

mitral stenosis 112-13,

transmit power 18

subcostal window 60-1

434-5

transoesophageal

supraclavicular window 60

mitral valve, preoperative

echocardiography (TOE)

suprasternal view 92-3, 104

assessment 436-7

advantages over TTE 344

suprasternal window 60-1

mitral valve

analgesia 358

swinging right atrium and

prolapse 128-9, 428-9

antibiotic prophylaxis 349

ventricle 300

mitral valve views 404-5

aortic views 400-1

systemic vascular

near real-time (full

atrial septum (bicaval)

resistance 642-3

volume) images 34-5

view 380-1

systolic anterior (leaflet)

oesophageal views 402-3

cleaning the probe 354-5

motion, mitral

opacification/

complications 348

valve 439, 446

compression 42

contraindications 348

systolic dyssynchrony

parasternal views 76-7

coronary sinus view 386-7

index 258

post processing 40-1

deep transgastric

pulmonary valve view 408

view 396-7

right ventricular size

five chamber view 370-1

266-7

four chamber view 368-9

TAPSE 273-4

slice modes 40-1

heating/thermal cutout 54

Teichholz method 210

smoothness 42

history of

TEI index 272-3

speckle tracking 46-7,

development 344

temporal resolution 20

244-5

ICU 345

INDEX

687

image acquisition 364-6

transgastric short axis

transducers (probes)

indications 346

view 388-9

4-5, 21

information for

two chamber (atrial

triplane imaging 64-5

patients 350

appendage) view 382-3

2D image acquisition

intraoperative 345, 438

X-plane 414-15

60-1

intubation 362-3

transseptal puncture

2D image optimization 59

left lower pulmonary vein

guidance 560

windows 60-1

view 384-5

transthoracic

xPlane imaging 64-5

left upper pulmonary vein

echocardiography (TTE)

transvalvular

view 384-5

abdominal aorta view 90-1

regurgitation 186-7

local anaesthetic 358

apical five chamber

transverse sinus 296, 510

long axis (aortic valve)

view 80-1, 102

traumatic aortic

view 376-7

apical four chamber

disruption 526

long axis (mitral valve)

view 78-9, 100-1

treadmill protocol 612-13

apical three chamber

tricuspid annular plane

oesophageal varices 348

view 84-5, 103

systolic excursion

oversedation in older

apical two chamber

(TAPSE) 273-4

patients 358

view 82-3, 103

tricuspid regurgitation

perforation risk 348

biplane imaging 64

carcinoid syndrome 166

post-procedure care 360

data acquisition 66-7

causes 157

preparation 352-3

digital storage 66

continuous wave

probe movements 356-7

ECG electrodes 56

Doppler 158-9

probe preparation 354-5

gel 58

contrast echo 574-5

pulmonary artery

image compression 67

grading severity 157-8,

view 398-9

image formats 66

159, 668

pulmonary vein

image quality 96

hepatic vein outflow 158

views 384-5

image storage 66

jet area 158

right lower pulmonary

inferior vena cava

pacemakers 156

vein view 384-5

view 90-1

physiological 156

right upper pulmonary

iRotate imaging 64

right ventricular

vein view 384-5

machine and probe

inflow 158

right ventricle inflow-

preparation 58

right ventricular systolic

outflow view 374-5

minimal data set 96-104

pressure 162-3

screenwiper

multiplane image

3D assessment 160-1

principle 364-6

acquisition 64-5

TOE 468-9

sedation 358-60

operator positioning 58

TTE 156

short axis (aortic valve)

parasternal long axis

vena contracta 158-9

view 372-3

view 68-9, 97

tricuspid stenosis

short axis (right ventricle)

parasternal right ventricle

3D assessment 164

view 374-5

inflow view 70-1

TOE 468

3D aorta view 406

parasternal right ventricle

TTE 164-5

3D aortic valve

outflow view 70-1

tricuspid valve

views 406-7

parasternal short axis

anatomy 154

3D atrial septum

(aortic) view 72-3, 99

area 164

view 412-13

parasternal short axis

normal TOE

3D left ventricle

(mitral) view 74-5, 98

findings 468

view 410-11

parasternal short axis

normal TTE findings

3D mitral valve

(ventricle) view 74-5, 98

154-5

views 404-5

parasternal 3D views 76-7

reporting 667

3D oesophageal

patient information 56

surgery 166

views 402-3

patient positioning 56

vegetations 166-7

3D pulmonary valve

patient preparation 56

tricuspid velocity 162-3

probe handling and

triplane imaging 64-5

3D tricuspid valve

movements 58

Tristel sporicidal wipe 355

view 408-9

quality of recordings 96

truncated ellipsoid

transducers (probes)

right parasternal view 94-5

model 212

6-7, 21

standard examination

tumours 306, 326-7, 329

transgastric long axis

96-104

tunica adventitia 308

(aortic) view 392-3

standard sequence of

tunica intima 308

transgastric long axis

two chamber (atrial

view 390-1

subcostal views 88-9, 104

appendage) view

transgastric right ventricle

suprasternal view 92-3,

382-3

view 394-5

104

2D-mode 8-9

688

INDEX

apical two chamber 82-3,

3D oesophageal 402-3

103

3D parasternal 76-7

Ultra ICE™ 549

atrial septal 552-3

3D pulmonary

ultrasound 2-3, 12-13

atrial septum

valve 408

ultrasound-triggered drug

(bicaval) 380-1

3D tricuspid valve

and gene delivery 577

coronary sinus 386-7

408-9

deep transgastric 396-7

transgastric long

five chamber 370-1

axis 390-1

four chamber 368-9

transgastric long axis

Valsalva manoeuvre

inferior vena cava 90-1

(aortic) 392-3

mitral inflow 246

left atrial appendage 554

transgastric right

shunt studies 506, 572

left ventricle 554-5

ventricle 394-5

valve cysts 328-9

long axis (aortic

transgastric short

variance mapping 30

valve) 376-7

axis 388-9

vascular access, ICE 550-1

long axis (mitral

two chamber (atrial

vascular transducers 4, 21

valve) 378

appendage) 382-3

vasodilator stress

mitral valve 554-5

X-plane 414-15

echocardiography

parasternal long axis

volume overload 276-7

618-19

68-9, 97

volume status 636-9

vegetations 166-7, 188-9,

parasternal right ventricle

volumetric flow 50

472-3, 530

inflow 70-1

VV delay 260-1

prosthetic valves 182

parasternal right ventricle

velocity time integral 50

outflow 70-1

vena contracta 120, 144-5,

parasternal short axis

148, 158-9, 422

(aortic) 72-3, 99

wall motion 234, 480

ventricle, single 337-8

parasternal short axis

wall motion score 234

ventricle outflow

(mitral) 74-5, 98

wall motion score

obstruction, post mitral

parasternal short axis

index 234

valve repair 446

(ventricle) 74-5, 98

wall thickness 210-11, 218,

ventricular aneurysm

pulmonary artery 398-9

270-1, 486, 597

resection 534

pulmonary vein 384-5,

washing jets 178, 448

ventricular reserve 140

554-5

weaning

ventricular septal

right parasternal 94-5

failure to wean off

defects 294-5, 508-9

right ventricle 554-5

bypass 533

ventricular septum 210-11,

right ventricle inflow-

from ventilator 646-7

292-3, 508, 658

outflow 374-5

left ventricular assist

ViewFlex® 549

short axis (aortic

devices 542

views

valve) 372-3

Wilkin’s score 444

abdominal aorta 90-1

short axis (right

windows 60, 61-2, 63

aortic 400-1

ventricle) 374-5

aortic valve and

subcostal 88-9, 104

root 552-3

suprasternal 92-3, 104

apical five chamber 80-1,

3D aorta 406

3D aortic valve 406-7

X-plane 64-5, 414-15

102

apical four chamber 78-9,

3D apical 86-7

100-1

3D atrial septum 412-13

apical three chamber

3D left ventricle 410-11

84-5, 103

3D mitral valve 404-5

z-score 312