12 Guidelines ESC Chamber Quantification Lang JASE 2005

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GUIDELINES

Recommendations for chamber quantication *

Roberto M. Lang, Michelle Bierig, Richard B. Devereux,Frank A. Flachskampf *, Elyse Foster, Patricia A. Pellikka,Michael H. Picard, Mary J. Roman, James Seward,Jack Shanewise, Scott Solomon, Kirk T. Spencer,Martin St. John Sutton, William Stewart

Med. Klinik 2, Erlangen University, Ulmenweg 18, 91054 Erlangen, Germany

Received 7 November 2005; accepted 23 December 2005Available online 2 February 2006

KEYWORDSStandards;Measurements;Volumes;Linear dimensions;

Quantication

Abstract Quantication of cardiac chamber size, ventricular mass and functionranks among the most clinically important and most frequently requested tasks ofechocardiography. Over the last decades,echocardiographic methods and techniqueshaveimproved andexpandeddramatically,due to theintroduction of higher frequencytransducers,harmonic imaging, fully digital machines, left-sided contrast agents, and

other technological advancements. Furthermore, echocardiography due to its porta-bility and versatility is now used in emergency rooms, operating rooms, and intensivecare units. Standardization of measurements in echocardiography has been inconsis-tent and less successful, compared to other imaging techniques and consequently,echocardiographic measurements are sometimes perceived as less reliable. There-fore, the American Society of Echocardiography, working together with the EuropeanAssociation of Echocardiography, a branch of the European Society of Cardiology, hascritically reviewed the literature and updated the recommendations for quantifyingcardiac chambers using echocardiography. This document reviews the technicalaspects on how to perform quantitative chamber measurements of morphology andfunction, which is a component of every complete echocardiographic examination. 2006 The European Society of Cardiology. Published by Elsevier Ltd. All rightsreserved.

Abbreviations: LV, left ventricle; LA, left atrium; RA, right atrium; RV, right ventricle; LVID, left ventricular internal dimension;LVIDd, left ventricular internal dimension at end diastole; LVIDs, left ventricular internal dimension at end systole; SWTd, septal wallthickness at end-diastole; PWTd, posterior wall thickness at end-diastole; EBD, endocardial border delineation; TEE, transesophagealechocardiography; MI, myocardial infarction.

* A report from the American Society of Echocardiographys Nomenclature and Standards Committee and the Task Force on Cham-ber Quantication, developed in conjunction with the American College of Cardiology Echocardiography Committee, the AmericanHeart Association, and the European Association of Echocardiography, a branch of the European Society of Cardiology.

* Corresponding author. Tel.: 49 9131 853 5301; fax: 49 9131 853 5303.E-mail address: [email protected] (F.A. Flachskampf).

1525-2167/$32 2006 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.doi:10.1016/j.euje.2005.12.014

Eur J Echocardiography (2006) 7 , 79e 108
mailto:[email protected]:[email protected]


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Introduction

Quantication of cardiac chamber size, ventricular mass and function ranks among the most clinicallyimportant and most frequently requested tasks ofechocardiography. Standardization of chamber quantication has been an early concern in echo-

cardiography and recommendations on how tomeasure such fundamental parameters are amongthe most often cited papers in the eld. 1,2 Over the last decades, echocardiographic methods andtechniques have improved and expanded dramati-cally. Improvements in image quality have beensignicant, due to the introduction of higher fre-quency transducers, harmonic imaging, fully digi-tal machines, left-sided contrast agents, andother technological advancements.

Furthermore, echocardiography has become thedominant cardiac imaging technique, which due toits portability and versatility is now used inemergency rooms, operating rooms, and intensivecare units. Standardization of measurements inechocardiography has been inconsistent and lesssuccessful, compared to other imaging techniquesand consequently, echocardiographic measure-ments are sometimes perceived as less reliable.Therefore, the American Society of Echocardiog-raphy, working together with the European Asso-ciation of Echocardiography, a branch of theEuropean Society of Cardiology, has criticallyreviewed the literature and updated the recom-mendations for quantifying cardiac chambers using

echocardiography. Not all the measurements de-scribed in this document can be performed in allpatients due to technical limitations. In addition,specic measurements may be clinically pertinentor conversely irrelevant in different clinic scenar-ios. This document reviews the technical aspectson how to perform quantitative chamber measure-ments and is not intended to describe the standardof care of which measurements should be per-formed in individual clinical studies. However,evaluation of chamber size and function is a com-ponent of every complete echocardiographic

examination and these measurements may havean impact on clinical management.

General overview

Enhancements in imaging have followed techno-logical improvements such as broadband trans-ducers, harmonic imaging and left-sided contrastagents. Nonetheless, image optimization stillrequires considerable expertise and attention tocertain details that are specic to each view

(Table 1 ). In general, images optimized for quanti-tation of one chamber may not necessarily be op-timal for visualization or measurement of other cardiac structures. The position of the patient dur-ing image acquisition is important. Optimal views

are usually obtained with the patient in the steepleft-lateral decubitus position using a cut-out mat-tress to permit visualization of the true apex whileavoiding LV foreshortening. The patients left armshould be raised to spread the ribs. Excessivetranslational motion can be avoided by acquiringimages during quiet respiration. If images areobtained during held end-expiration, care mustbe taken to avoid a Valsalva maneuver, whichcan degrade image quality.

Digital capture and display of images on theechocardiographic system or on a workstationshould optimally display images at a rate of atleast 30 frames/second. In routine clinical prac-tice a representative cardiac cycle can be used for measurement as long as the patient is in sinusrhythm. In atrial brillation, particularly whenthere is marked RR variation, multiple beatsshould be used for measurements. Averaging mea-surements from additional cycles may be particu-larly useful when R-R intervals are highly irregular.When premature atrial or ventricular contractionsare present, measurements should be avoided inthe post-ectopic beat since the length of the

Table 1 Elements of image acquisition andmeasurement for two-dimensional quantitation

Aim Method

Minimize translationalmotion

Quiet or suspendedrespiration (at end-expiration)

Maximize imageresolution

Image at minimum depthnecessaryHighest possible transducer frequencyAdjust gains, dynamic range,transmit and lateral gaincontrols appropriatelyFrame rate 30/sHarmonic imagingB-color imaging

Avoid apicalforeshortening

Steep lateral decubituspositionCut-out mattressAvoid reliance on palpable

apical impulseMaximize endocardialborder

Contrast enhancementdelineation

Identifyend-diastoleand end-systole

Mitral valve motion andcavity size rather thanreliance on ECG

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preceding cardiac cycle can inuence ventricular volume and ber shortening.

Harmonic imaging is now widely employed inclinical laboratories to enhance the images espe-cially in patients with poor acoustic windows.While this technology reduces the drop-out ofendocardial borders, the literature suggests that

there is a systemic tendency for higher measure-ments of LV wall thickness and mass and smaller measu re ments of internal dimensions and vol-umes. 3,4 When analyzing serial studies on a givenpatient, differences in chamber dimension poten-tially attributable to imaging changes from thefundamental to the harmonic modality are probablysmaller than the inter and intra-observer variabil-ity of these measurements. The best techniquefor comparing serial changes in quantitation is todisplay similar serial images side-by-side andmake the same measurement on both images bythe same person, at the same time. 5 It is importantto note that most measurements presented in thismanuscript are derived from fundamental imagingas normative values have not been establishedusing harmonic imaging.

Left-sided contrast agents used for endocardialborder delineation (EBD) are helpful and improvemeasurement reproducibility for suboptimal stud-ies and correlation with other imaging techniques.While the use of contrast agents has beenreviewed elsewhere in detail, 6 a few caveats re-garding their use deserve mention. The mechanicalindex should be lowered to decrease the acoustic

power of the ultrasound beam, which reduces bub-ble destruction. The image should be focusedon the structure of interest. Excessive shadowingmay be present during the initial phase of bubbletransit and often the best image can be recordedseveral cardiac cycles following the appearanceof contrast in the left ventricle. When less than80% of the endocardial border is adequately visual-ized, the use o f contrast agents for EBD is stronglyrecommended. 7 By improving visualization of theLV apex, the problem of ventricular foreshorteningis reduced and correlation with other techniquesimproved. Contrast enhanced images should belabeled to facilitate the reader identication ofthe imaging planes.

Quantitation using transesophageal echocardi-ography (TEE) has advantages and disadvantagescompared to transthoracic echocardiography(TTE). Although visualization of many cardiacstructures is improved with TEE some differencesin measurements have been found between TEEand TTE. These differences are primarily attribut-able to the inability to obtain from the trans-esophageal approach the standardized imaging

planes/views used when q uantifying chamber di-mensions transthoracically. 8,9 It is the recommen-dation of this writing group that the same rangeof normal values for chamber dimensions and vol-umes apply for both TEE and TTE. In this manu-script, recommendations for quantication usingTEE will primarily focus on acquisition of images

that allow measurement of cardiac structuresalong imaging planes that are analogous to TTE.In addition to describing a parameter as normal

or abnormal (reference values), clinical echocar-diographers most often qualify the degree ofabnormality with terms such as mildly, mod-erately or severely abnormal. Such a descrip-tion allows the clinician to not only understandthat the parameter is abnormal but also thedegree to which their patients measurementsdeviate from normal. In addition to providingnormative data it would be benecial to standard-ize cutoffs for severity of abnormality acrossechocardiographic laboratories, such that moder-ately abnormal had the same implication in alllaboratories. However, multiple statistical tech-niques exist for determining threshol ds values, allof which have signicant limitations. 10

The rst approach would be to dene cutoffsempirically for mild, moderate and severe abnor-malities based on standard deviations above/below the reference limit derived from a groupof normal subjects. The advantage of this methodis that this data readily exists for most echocar-diographic parameters. However, this approach

has several disadvantages. Firstly, not all echocar-diographic parameters are normally distributed, or Gaussian in nature, making the use of standarddeviation questionable. Secondly, even if a partic-ular parameter is normally distributed in controlsubjects, most echocardiographic parameterswhen measured in the general population havea signicant asymmetric distribution in one di-rection (abnormally large for size or abnormallylow for function parameters). Using the standarddeviation derived from normal subjects leads toabnormally low cutoff values which are inconsis-tent with clinical experience, as the standarddeviation inadequately represents the magnitudeof asymmetry (or range of values) towards abnor-mality. This is the case with LV ejection fraction(EF) where 4 standard deviations below the mean(64 G 6.5) results in a cutoff for severely abnormalof 38%.

An alternative method would be to deneabnormalities based on percentile values (95th,99th, etc.) of measurements derived from a pop-ulation that includes bo th normal subjects andthose with disease states. 11 Although this data may

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still not be Gaussian, it accounts for the asymmet-ric distribution and range of abnormality presentwithin the general population. The major limita-tion of this approach is that large enough popula-tion data sets simply do not exist for mostechocardiographic variables.

Ideally, an approach that would predict out-

comes or prognosis would be preferred. That isdening a variable as moderately deviated fromnormal would imply that there is a moderate riskof a particular adverse outcome for that patient.Although sufcient data linking risk and cardiacchamber sizes exist for several parameters (i.e.,EF, LV size, LA volume); risk data are lacking for many other parameters. Unfortunately, this ap-proach continues to have several limitations. Therst obstacle is how to best dene risk. Thecutoffs suggested for a single parameter varybroadly for the risk of death, myocardial infarction(MI), atrial brillation etc. In addition, much of therisk literature applies to specic populations (post-MI, elderly), and not general cardiovascular riskreadily applicable to consecutive patients studiedin an echocardiography laboratory. Lastly, al-though having data specically related to risk isideal, it is not clear that this is necessary. Perhapscardiac risk rises inherently as echocardiographicparameters become more abnormal. This has beenshown for several echocardiographic parameters(LA dimension, wall thickness, LV size and LV mass)which, when partitioned based on populationestimates, demo nstrated graduated risk, which is

often non-linear.11

Lastly cutoffs values may be determined fromexpert opinion. Although scientically least rigor-ous, this method takes into account the collectiveexperience of having read and measured tens ofthousands of echocardiograms.

No single methodology could be used for allparameters. The tables of cutoffs represent a con-sensus of a panel of experts using a combination ofthe methods described above ( Table 2 ). The con-sensus values are more robust for some parametersthan others and future research may redene thecutoff values. Despite the limitations, these parti-tion values represent a leap forward towards thestandardization of clinical echocardiography.

Quantication of the left ventricle

Left ventricular dimensions, volumes and wallthicknesses are echocardiographic measurem entswidely used in clinical practice and research. 12,13

LV size and performance are still frequently visu-ally estimated. However, qualitative assessment

of LV size and function may have signicant in-ter-observer variability and is a function of inter-preter skill. Therefore, it should regularly becompared to quantitative measurements, espe-cially when different views qualitatively suggestdifferent degrees of LV dysfunction. Similarly, itis also important to cross-check quantitative datausing the eye-ball method, to avoid overempha-sis on process-related measurements, which attimes may depend on structures seen in a singlestill-frame. It is important to account for the inte-

gration over time of moving structures seen in oneplane, and the integration of three-dimensionalspace obtained from viewing a structure in multi-ple orthogonal planes. Methods for quantitationof LV size, mass and function usin g two-dimen-sional imaging have been validated. 14 e 17

There are distinct advantages and disadvan-tages to each of the accepted quantitativemethods ( Table 3 ). For example, linear LV mea-surements have been widely validated in the man-agement of valvular heart disease, but maymisrepresent dilatation and dysfunction in pa-tients with regional wall motion abnormalitiesdue to coronary artery disease. Thus, laboratoriesshould be familiar with all available techniquesand peer review literature and should apply themon a selective basis.

General principles for linear andvolumetric LV measurements

To obtain accurate linear measurements of in-terventricular septal and posterior wall thick-nesses and LV internal dimension, recordings

Table 2 Methods used to establish cutoff values ofdifferent echocardiographic parameters

Standarddeviation

Percentile Risk Expertopinion

Septal wallthickness

U U

LV mass U ULV dimensions U ULV volumes ULV function

linear methodU

Ejection fraction U URV dimensions UPA diameters URV areas URV function ULA dimensions ULA volumes U U URA dimensions U

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should be made from the parasternal long-axisacoustic window. It is recommended that LV in-ternal diameters (LVIDd and LVIDs, respectively)and wall thicknesses be measured at the level ofthe LV minor axis, approximately at the mitralvalve leaet tips. These linear measurements canbe made directly from 2D images or using 2D-targeted M-mode echocardiography.

By virtue of their high pulse rate, M-moderecordings have excellent temporal resolutionand may complement 2-D images in separatingstructures such as trabeculae adjacent to theposterior wall, false tendons on the left side ofthe septum, and tricuspid apparatus or moderator band on the right side of the septum from theadjacent endocardium. However, it should berecognized that even with 2D guidance, it maynot be possible to align the M-mode cursor per-pendicular to the long axis of the ventricle which ismandatory to obtain a true minor axis dimensionmeasurement. Alternatively, chamber dimensionand wall thicknesses can be acquired from theparasternal short-axis view using direct 2D mea-surements or targeted M-mode echocardiography

provided that the M-mode cursor can be positionedperpendicular to the septum and LV posterior wall.A 2D method, useful for assessing patients with

coronary artery disease has been proposed. Whenusing this method, it is recommended that LVinternal diameters (LVIDd and LVIDs, respectively)and wall thicknesses be measured at the level ofthe LV minor dimension, at the mitral chordaelevel. These linear measurements can also bemade directly from 2D images or using 2D-targetedM-mode echocardiography. Direct 2D minor axismeasurements at the chordae level intersect theinterventricul ar se ptum below the left ventricular outow tract, 2,5,18 and thus provides a global as-sessment in a symmetrically contracting LV, andalso evaluates basal regional function in a chamber with regional wall motion abnormalities. Thedirect 2D minor axis dimensions are smaller thanthe M-mode measurements with the upper limitsof normal of LVIDd being 5.2 cm vs 5.5 cm andthe lower limits of normal for fractional shorteningbeing 0.18 vs 0.25. Normal systolic and diastolicmeasurements reported for this parameter ar e4.7 G 0.4 cm and 3.3 G 0.5 cm, respectively. 2,18

Table 3 LV quantication methods: utility, advantages and limitations

Dimension/volumes Utility/advantages Limitations

Linear M-mode Reproducible

e High frame rates e Beam orientation frequently off-axise Wealth of accumulated

datae Single dimension may not be

representative in distorted ventriclese Most representative in normally

shaped ventricles

2-D guided e Assures orientation perpendicular to ventricular long-axis

e Lower frame rates than in M-modee Single dimension only

VolumetricBiplane Simpsons e Corrects for shape distortions e Apex frequently foreshortened

e Minimizes mathematical assumptions e Endocardial dropoute Relies on only two planese Little accumulated data on normal

populationArea length e Partial correction for shape distortion e Based on mathematical assumptions

e Little accumulated data

MassM-mode or 2-D guided e Wealth of accumulated data e Inaccurate in ventricles with regional

abnormalitiese Beam orientation (M-mode)e Small errors magniede Overestimates LV mass

Area length e Allows for contribution ofpapillary muscles

e Insensitive to distortion inventricular shape

Truncated ellipsoid e More sensitive to distortions inventricular shape

e Based on a number or mathematicalassumptions

e Minimal \normal data



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LVID and septal and posterior wall thicknesses(SWT and PWT, respectively) are measured at end-diastole (d) and end-systole (s) from 2-D or M-moderecordin gs, 1,2 preferably on several cardiac cycles(Fig. 1). 1,2 Renements in image processing haveallowed improved resolution of cardiac structures.Consequently, it is now possible to measure the ac-

tual visualized thickness of the ventricular septumand other chamber dimensions as dened by theactual tissue e blood interface, rather than the dis-tance between the leading edge echoes which hadpreviously been recommended. 5 Use of 2-D echo-derived linear dimensions overcomes the commonproblem of oblique parasternal images resultingin overestimation of cavity and wall dimensionsfrom M mode. If manual calibration of images isrequired, 6 cm or larger distances should be usedto minimize errors due to imprecise placement ofcalibration points.

In order to obtain volumetric measurements themost important views for 2-D quantitation are themid-papillary short-axis view and the apical four-and two-chamber views. Volumetric measurementsrequire manual tracing of the endocardial border.The papillary muscles should be excluded from thecavity in the tracing. Accurate measurementsrequire optimal visualization of the endocardialborder in order to minimize the need for extrapo-lation. It is recommended that the basal border ofthe LV cavity area be delineated by a straight line

connecting the mitral valve insertions at the lateraland septal borders of the annulus on the four-chamber view and the anterior and inferior annular borders on the two-chamber view.

End-diastole can be dened at the onset of theQRS, but is preferably dened as the framefollowing mitral valve closure or the frame in the

cardiac cycle in which the cardiac dimension islargest. In sinus rhythm, this follows atrial con-traction. End-systole is best dened as the framepreceding mitral valve opening or the time in thecardiac cycle in which the cardiac dimension issmallest in a normal heart. In the two-chamber view, mitral valve motion is not always clearlydiscernible and the frames with the largest andsmallest volumes should be identied as end-diastole and end-systole, respectively.

The recommended TEE views for measurementof LV diameters are the mid esophageal two-chamber view ( Fig. 2) and the transgastric (TG)two- chamber views ( Fig. 3). LV diameters aremeasured from the endocardium of the anterior wall to the endocardium of the inferior wall ina line perpendicular to the long-axis of the ventri-cle at the junction of the basal and middle thirdsof the long-axis. The recommended TEE view for measurement of LV wall thicknesses is the TGmid short-axis view ( Fig. 4). With TEE, the long-axis dimension of the LV is often foreshortened inthe mid-esophageal four-chamber and long-axis

Figure 1 Measurement of left ventricular end-diastolic diameter (EDD) and end-systolic diameter (ESD) fromM-mode, guided by a parasternal short axis image (upper left) to optimize medial-lateral beam orientation.

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views; therefore the mid-esophageal two-chamber view is preferred for this measurement. Care mustbe made to avoid foreshortening TEE views, by re-cording the image plane which shows the maxi-mum obtainable chamber size, nding the anglefor diameter measurement which is perpendicular to the long-axis of that chamber, then measuringthe maximum obtainable short-axis diameter.

Calculation of left ventricular mass

In clinical practice, LV chamber dimensions arecommonly used to derive measures of LV systolicfunction, whereas in epidemiologic studies andtreatment trials, the single largest application ofechocardiography has been the estimation of LVmass in populations and its change with antihy-pertensive therapy. 13,19 All LV mass algorithms,

whether utilizing M-mode, 2-D or 3-D echocardio-graphic measurements, are based upon subtrac-tion of the LV cavity volume from the volumeenclosed by the LV epicardium to obtain LV muscleor shell volume. This shell volume is then con-verted to mass by multiplying by myocardial den-sity. Hence, quantitation of LV mass requiresaccurate identication of interfaces between thecardiac blood pool and endocardium and betweenepicardium and pericardium.

To date, most LV mass calculations have beenmade using linear measurements derived from 2-D-targeted M-mode or, m ore recently, from 2-Dlinear LV measurements. 20 The ASE recommendedformula for estimation of LV mass from LV linear dimension s (validated with necropsy r 0.90, p < 0.001 21 ) is based on modeling the LV as aprolate ellipse of revolution:

Figure 2 Transesophageal measurements of left ventricular length (L) and minor diameter (LVD) from the mid-esophageal two-chamber view, usually best imaged at a multiplane angle of approximately 60 e 90 degrees.

Figure 3 Transesophageal echo measurements of left ventricular minor axis diameter (LVD) from the trans-gastrictwo-chamber view of the left ventricle, usually best imaged at an angle of approximately 90 e 110 degrees after op-timizing the maximum obtainable LV size by adjustment of medial-lateral rotation.



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LV mass 0:8 1:04LVIDd PWTd

SWTd3 LVIDd3 0:6 g

This formula is appropriate for evaluating pa-tients without major distortions of LV geometry,e.g., patients with hypertension. Since this for-mula requires cubing primary measurements, evensmall errors in these measurements are magnied.Calculation of relative wall thickness (RWT) by theformula, (2 PWTd)/LVIDd, permits categoriza-tion of an increase in LV mass as either concentric(RWT 0.42) or eccentric (RWT 0.42) hypertro-phy and allows identication of concentric

remodel ing (normal LV mass with increased RWT)(Fig. 5). 22

The most commonly employed 2-D methods for measuring LV mass are based on the area e lengthformula and the truncated ellipsoid model, asdescribed in det ail in the 1989 ASE document onLV quantitation. 2 Both methods were validated inthe early 1980s in animal models and by comparingpre-morbid echocardiograms with measured LVweight at autopsy in humans. Both methods relyon measurements of myocardial area at the mid-papillary muscle level. The epicardium is tracedto obtain the total area ( A1) and the endocardiumis traced to obtain the cavity area ( A2). Myocardial

Figure 4 Transesophageal echo measurements of wall thickness of the left ventricular septal wall (SWT) and theposterior wall (PWT), from the trans-gastric short axis view of the left ventricle, at the papillary muscle level, usuallybest imaged at angle of approximately 0 e 30 degrees.

Figure 5 Comparison of relative wall thickness (RWT). Patients with normal LV mass can have either concentricremodeling (normal LV mass with increased RWT > 0.42) or normal (RWT 0.42) and normal LV mass. Patients withincreased LV mass can have either concentric (RWT > 0.42) or eccentric (RWT 0.42) hypertrophy. These LV massmeasurements are based on linear measurements.

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wall t hicknesses based on mathematicalmodels, 30,31 according to the following formulas:

Inner shell hLVIDd SWTd=2 PWTd=2 3

LVIDd3 LVIDs31=3

LVIDs

The most commonly used 2-D measurement for volume measurements is the biplane method ofdiscs (modied Simpsons rule) and is the currentlyrecommended method of choice by consensus ofthis committee ( Fig. 7). The principle underlyingthis method is that the totalLV volume is calculated

from the summation of a stack of elliptical discs.The height of each disc is calculated as a fraction(usually one-twentieth) of the LV long axis basedon the longer of the two lengths from the two-and four-chamber views. The cross-sectional area

of the disk is based on the two diameters obtainedfrom the two- and four-chamber views. When twoadequate orthogonal views are not available, a sin-gle plane can be used and the area of the disc isthen assumed to be circular. The limitations of

using a single plane are greatest when extensivewall motion abnormalities are present.

An alternative method to calculate LV volumeswhen apical endocardial denition precludes ac-curate tracing is the area e length method wherethe LV is assumed to be bullet-shaped ( Fig. 6). The

mid LV cross-sectional area is computed by planim-etry in the parasternal short-axis view andthe length of the ventricle taken from the midpoint of the annulus to the apex in the apicalfour-chamber view. These measurements are

Figure 7 2-D measurements for volume calculations using the biplane method of discs (modied Simpsons rule), inthe apical four-chamber (A4C) and apical two-chamber (A2C) views at end diastole (LV EDD) and at end-systole (LVESD). The papillary muscles should be excluded from the cavity in the tracing.

MWFSLVIDd SWTd=2 PWTd=2 LVIDs inner shell

LVIDd SWTd=2 PWTd=2 100

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virtually identical to those based on direct nec-ropsy mea surement a nd cutoff values used in clin-ical trials. 19,20,36,38,39 Although some prior studieshave suggested racial differences in LV mass mea-surement, the consensus of the literature avail-able indicates that no signicant differencesexist between clinically normal black and white

subjects. In contrast, a recent study has shownracial-ethnic difference s in left ventricular structurein hypertensive adults. 40 Although the sensitivity,specicity and predictive value of LV wall thick-ness measurements for detection of LV hypertro-phy are lower than for calculated LV mass, it issometimes easiest in clinical practice to identifyLV hypertrophy by measurin g an increased LVposterior and septal thickness. 41

The use of LV mass in children is complicated bythe need for indexing the measurement relative topatient body size. The intent of indexing is toaccount for normal childhood growth of lean bodymass without discounting the pathologic effects ofoverweight and obesity. In this way, an indexed LVmass measurement in early childhood can bedirectly compared to a subsequent measurementduring adolescence and adulthood. Dividing LVmass by height raised to a power of 2.5 e 3.0 isthe most widely accepted indexing method inolder children and adolescents since it cor re latesbest to indexing LV mass to lean body mass. 42 Cur-rently an intermediate value of 2.7 is generallyused. 43,44 In younger children ( < 8 years), themost ideal indexing factor remains an area of re-

search, but height raised to a power of 2.0 appearsto be the most appropriate. 45

Three-dimensional assessmentof volume and mass

Three-dimensional chamber volume and mass areincompletely characterized by one-dimensional or two-dimensional approaches, which are based ongeometric assumptions. While these inaccuracieshave been considered inevitable and of minor clinical importance in the past, in most situationsaccurate measurements are required, particularlywhen following the course of a disease with serialexaminations. Over the last decade, several three-dimensional echocardiographic techniques be cameavailable to measure LV volumes and mass. 46 e 59

These can be conceptually divided into tech-niques, which are based on off-line reconstructionfrom a set of 2-D cross-sections, or on-line dataacquisition using a matrix array transducer, alsoknown as real-time 3-D echocardiography. After acquisition of the raw data, calculation of LVvolumes and mass requires identication of

T a b l e 5

R e f e r e n c e l i m i t s a n d p a r t i t i o n v a l u e s o f l e f t v e n t r i c u l a r s i z e

W o m e n

M e n

R e f e r e n c e

r a n g e

M i l d l y

a b n o r m a l

M o d e r a t e l y

a b n o r m a l

S e v e r e l y

a b n o r m a l

R e f e r e n c e

r a n g e

M i l d l y

a b n o r m a l

M o d e r a t e l y

a b n o r m a l

S e v e r e l y

a b n o r m a l

L V d i m e n s i o n

L V d i a s t o l i c d i a m e t e r

3 . 9 e 5 . 3

5 . 4 e 5 . 7

5 . 8

e 6 . 1

6 . 2

4 . 2 e 5 . 9

6 . 0 e 6 . 3

6 . 4 e 6 . 8

6 . 9

L V d i a s t o l i c d i a m e t e r / B S A ( c m / m 2 )

2 . 4 e 3 . 2

3 . 3 e 3 . 4

3 . 5

e 3 . 7

3 . 8

2 . 2

e 3 . 1

3 . 2 e 3 . 4

3 . 5 e 3 . 6

3 . 7

L V d i a s t o l i c d i a m e t e r / h e i g h t

( c m / m )

2 . 5 e 3 . 2

3 . 3 e 3 . 4

3 . 5

e 3 . 6

3 . 7

2 . 4

e 3 . 3

3 . 4 e 3 . 5

3 . 6 e 3 . 7

3 . 8

L V v o l u m e

L V d i a s t o l i c v o l u m e ( m l )

5 6 e

1 0 4

1 0 5 e 1 1 7

1 1 8

e 1 3 0

1 3 1

6 7 e

1 5 5

1 5 6 e 1 7 8

1 7 9 e 2 0 1

2 0 1

L V d i a s t o l i c v o l u m e / B S A ( m l / m

2 )

3 5 e

7 5

7 6 e

8 6

8 7 e

9 6

9 7

3 5 e

7 5

7 6 e

8 6

8 7 e 9 6

9 7

L V s y s t o l i c v o l u m e ( m l )

1 9 e

4 9

5 0 e

5 9

6 0 e

6 9

7 0

2 2 e

5 8

5 9 e

7 0

7 1 e

8 2

8 3

L V s y s t o l i c v o l u m e / B S A ( m l / m

2 )

1 2 e

3 0

3 1 e

3 6

3 7 e

4 2

4 3

1 2 e

3 0

3 1 e

3 6

3 7 e 4 2

4 3

V a l u e s i n b o l d a r e r e c o m m e n d e d a n d b e s t v a l i d a t e d

.

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endocardial borders (and for mass epicardial bor-der) using manual or semi-automated algorithms.These borders are then processed to calculatethe c avit y or myocardial vo lume by summation ofdiscs 54,56 or other methods. 46 e 48

Regardless of which acquisition or analysismethod is used, 3-D echocardiography does notrely on geometric assumptions for volume/masscalculations and is not subject to plane positioningerrors, which can lead to chamber foreshortening.Studies comparing 3-D echocardiographic LV vol-umes or mass to other gold-standards such asmagnetic resonance imaging, have conrmed 3-Dechocardiography to be accurate. Compared tomagnetic resonance data, LV and RV volumes

calculated from 3-D echocardiography showedsignicantly better agreement (smaller bias), lower scatter and lower intra- and inter- observer vari-ability than 2-D echocardiography. 46,54,57,60 Thesuperiority of 3-D echocardiographic LV mass calcu-lationsover values calculated from M-mode derivedor 2-D echoc ardiography has been convincinglyshown. 55,57,59 Right ventricular volume and masshave also been measured by 3-D echocardiographywith good agreement with magnetic resonancedata. 58,61 Current limitations include the require-ment of regular rhythm, relative inferior imagequality of real-time 3-D echocardiography com-pared to 2-D images, and the time necessary for off-linedata analysis. However, thegreater number of acquired data points, the lack of geometricassumptions, increasingly sophisticated 3-D imageand measurements solutions offset theselimitations.

Regional left ventricular function

In 1989, the American Society of Echocardiographyrecommended a 16 segment model for LV

segmentation. 2 This model consists of six segmentsat both basal and mid-ventricular levels and four segments at the apex ( Fig. 8). The attachment ofthe right ventricular wall to the left ventricle de-nes the septum, which is divided at basal andmid LV levels into anteroseptum and inferoseptum.Continuing counterclockwise, the remaining seg-ments at both basal and mid ventricular levelsare labeled as inferior, inferolateral, anterolateraland anterior. The apex includes septal, inferior,lateral, and anterior segments. This model hasbecome widely utilized in echocardiography. Incontrast, nuclear perfusion imaging, cardiovascular magnetic resonance and cardiac computedtomography have commonly used a larger number

of segments.In 2002, the American Heart Association WritingGroup on Myocardial Segmentation and Registra-tion for Cardiac Imaging, in an attempt to establishsegmentation standards applicable to all typesof imaging, recommended a 17-segment model(Fig. 8). 62 This differs from the previous 16-segment model predominantly by the addition ofa 17th segment, the apical cap. The apicalcap is the segment beyond the end of the LVcavity. Renements in echocardiographic imaging,including harmonics and contrast imaging arebelieved to permit improved imaging of the apex.Either model is practical for clinical applicationyet sufciently detailed for semi-quantitativeanalysis. The 17-segment model should be predom-inantly used for myocardial perfusion studies or anytime efforts are made to compare betweenimaging modalities. The 16-segment model isappropriate for studies assessing wall motionabnormalities as the tip of the normal apex(segment 17) does not move.

The mass and size of the myocardium asassessed at autopsy is the basis for determining

Table 6 Reference limits and values and partition values of left ventricular function

Women Men

Referencerange

Mildlyabnormal

Moderatelyabnormal

Severelyabnormal

Referencerange

Mildlyabnormal

Moderatelyabnormal

Severelyabnormal

Linear method Endocardial

fractionalshortening (%)

27e 45 22e 26 17e 21 16 25e 43 20e 24 15e 19 14

Midwallfractionalshortening (%)

15e 23 13e 14 11e 12 10 14e 22 12e 13 10e 11 10

2-D method Ejection

fraction (%) 55 45 e 54 30 e 44 < 30 55 45 e 54 30 e 44 < 30

Values in bold are recommended and best validated.



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the distribution of segments. Sectioned into basal,mid ventricular and apical thirds, perpendicular tothe LV long-axis, with the mid ventricular thirddened by the papillary muscles, the measured

myocardial mass in adults without cardiac diseasewas 43% for the base, 36% for the mid cavity and21% for the apex. 63 The 16-segment model closelyapproximates this, creating a distribution of 37.5%for both the basal and mid portions and 25% for theapical portion. The 17-segment model createsa distribution of 35.3%, 35.3% and 29.4% for thebasal, mid and apical portions (including the apicalcap) of the heart, respectively.

Variability exists in the coronary artery bloodsupply to myocardial segments. Nevertheless, thesegments are usually attributed to the three major coronary arteries ar e shown in the TTE G dis-tributions of Fig. 9. 62

Since the 1970s, echocardiography has beenused for the evaluation of LV reg ional wall motionduring infarction and ischemia. 64 e 66 It is recog-nized that regional myocardial blood ow andregional LV systolic functio n are related over a wide range of blood ows. 67 Although regionalwall motion abnormalities at rest may not beseen until the luminal diameter stenosis exceeds85%, with exercise, a coronary lesion of 50% can re-sult in regional dysfunction. It is recognized that

echocardiography can overestimate the amountof ischemic or infarcted myocardium, as wallmotion of adjacent regions may be affected bytethering, disturban ce of regional loading condi-

tions and stunning.68

Therefore, wall thickeningas well as motion should be considered. Moreover,it should be remembered that regional wall motionabnormalities may occur in the absence of coro-nary artery disease.

It is recommended that each segment be ana-lyzed individually and scored on the basis of itsmotionandsystolic thickening. Ideally, thefunctionof each segment should be conrmed in multipleviews. A segment which is normal or hyperkineticis assigned a score of 1, hypokinesis 2, akinesis(negligible thickening) 3, dyskinesis (paradoxicalsystolic motion) 4, and aneurysmal (diastolicdeformation) 5. 1 Wall motion score index can bederived as a sum of all scores divided by the number of segments visualized.

Assessment of LV remodeling and the useof echocardiography in clinical trials

Left ventricular remodeling describes the processby which the heart changes its size, geometry andfunction over time. Quantitative 2-D transthoracic

Figure 8 Segmental analysis of LV walls based on schematic views, in a parasternal short and long axis orientation,at three different levels. The apex segments are usually visualized from apical four-chamber, apical two- andthree-chamber views. The apical cap can only be appreciated on some contrast studies. A 16 segment model canbe used, without the apical cap, as described in an ASE 1989 document. 2 A 17 segment model, including the apicalcap, has been suggested by the American Heart Association Writing Group on Myocardial Segmentation and Registra-tion for Cardiac Imaging. 62

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echocardiography enables characterization of LVremodeling that occurs in normal subjects and ina variety of heart diseases. LV remodeling may bephysiological when the heart increases in size butmaintains normal function during growth, physicaltraining and pregnancy. Several studies have dem-

onstrated that both isometric and isotonic exercisecause remodeling of the left and right vent ricular chamber sizes and wall thicknesses. 69 e 73 Thesechanges in the highly-trained, elite athletehearts are directly related to the type and dura-tion of exercise and have been characterized echo-cardiographically. With isometric exercise, adisproportionate increase occurs in LV mass com-pared to the increase in LV diastolic volume result-ing in signicantly greater wall thickness to cavitysize ratio ( h/ R ratio) than take place in normalnon-athletic subjects with no change in eje ctionphase indices of LV contractile function. 69 e 73 Thisphysiologic hypertrophic remodeling of the athleteheart is reversible with cessation of endurancetraining and is related to the total increase inlean body weight 70 and trig gered by enhanced car-diac sympathetic activity. 74 Remodeling may becompensatory in chronic pressure overload due tosystemic hypertension or aortic stenosis resultingin concentric hypertrophy (increased wall thick-ness, normal cavity volume and preserved ejectionfraction) ( Fig. 5). Compensatory LV remodelingalso occurs in chronic volume overload associated

with mitral or aortic regurgitation, which inducesa ventricular architecture characterized by eccen-tric hypertrophy, LV chamber dilatation and ini-tially normal contractile function. Pressure andvolume overload may remain compensated by ap-propriate hypertrophy which normalizes wall

stress such that hemodynamics and ejection frac-tion remain stable long term. However, in somepatients chronically increased afterload cannotbe normalized indenitely and the remodelingprocess becomes pathologic.

Transition to pathologic remodeling is heraldedby progressive ventricular dilatation, distortion ofcavity shape and disruption of the normal geome-try of the mitral annulus and subvalvular apparatusresulting in mitral regurgitation. The additionalvolume load from mitral regurgitation escalatesthe deterioration in systolic function and develop-ment of heart failure. LV dilatation begets mitralregurgitation and mitral regurgitation begets fur-ther LV dilatation, progressive remodeling andcontractile dysfunction.

Changes in LV size and geometry due to hyper-tension ( Fig. 5) reect the dominant underlyinghemodynamic altera tion s associated with bloodpressure elevation. 22,75 The pressure-overloadpattern of concentric hypertrophy is uncommonin otherwise healthy hypertensive individuals andis associated with high systolic blood pressureand high peripheral resistance. In contrast, eccentric

Figure 9 Artists diagram showing the position of three long axis views and one short axis view of the left ventricle,showing the typical distributions of the right coronary artery (RCA), the left anterior descending (LAD), and thecircumex (Cx) coronary arteries. The arterial distribution varies between patients. Some segments have variablecoronary perfusion.



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LV hypertrophy is associated with normal periph-eral resistance but high cardiac index consistentwith excess circulating blood volume. Concentricremodeling (normal LV mass with increased rela-tive wall thickness) is characterized by high pe-ripheral resistance, low car diac index, andincreased arterial stiffness. 76,77

A unique form of remodeling occurs followingmyocardial infarction due to the abrupt loss ofcontracting myocytes. 22,78 Early expansion of theinfarct zone is associated with early LV dilatationas the increased regional wall stress is redistrib-uted to preserve stroke volume. The extent ofearly and late post-infarction remodeling is deter-mined by a number of factors, including size andlocation of infarction, activation of the sympa-thetic nervous system, and up-regulation of therenin/angiotensin/aldosterone system and natri-uretic peptides. Between one-half and one-thirdof post-in farc tion patients experience progressivedilatation 79,80 with distortion of ventricular geom-etry and secondary mitral regurgitation. Mitralregurgitation further increases the propensity for deterioration in LV function and development ofcongestive heart failure. Pathologic LV remodelingis the nal common pathway to heart failure,whether the initial stimulus is chronic pressure or chronic volume overload, genetically determinedcardiomyopathy or myocardial infarction. The eti-ology of LV dysfunction in approximately two thirdsof the 4.9 million patients with heart failure in theUSA is coronary artery disease. 81

While LV remodeling in patients with chronicsystemic hypertension, chronic valvular regurgita-tion and primary cardiomyopathies has been de-scribed, the transition to heart failure is less wellknown because the time course is so prolonged. Bycontrast, the time course from myocardial infarc-tion to heart failure is shorter and has been clearlydocumented.

The traditional quantitative echocardiographicmeasurements recommended to evaluate LV re-modeling included estimates of LV volumes either from biplane or single plane images as advocatedby the American Society of Echocardiography.Although biplane and single-plane volume estima-tions are not interchangeable, both estimates areequally sensitive for detecting time-dependent LVremo deling and deteriorating contractile func-tion. 77 LV volumes and derived ejection fractionhave been demonstrated to predict adversecardiovascular events at follow-up, includingdeath, recurrent infarction, heart failure, ventric-ular arrhythmias and mitral regurgitation innume rous post-infarction and heart failuretrials. 78 e 81 This committee recommends the use

of quantitative estimation of LV volumes, LVEF,LV mass and shape as (described in the respectivesections above) to follow LV remodeling induced byphysiologic and pathologic stimuli. In addition,these measurements provide prognostic informa-tion incremental to that of baseline clinicaldemographics.

Quantication of the RV and RVOT

The normal right ventricle (RV) is a complexcrescent-shaped structure wrapped around theleft ventricle and is incompletely visualized inany single 2-D echocardiographic view. Thus,accurate assessment of RV morphology and func-tion requires integration of multiple echocardio-graphic views, including the parasternal long andshort-axis views, the RV inow view, the apicalfour-chamber and the subcostal views. Whilemultiple methods for quantitative echocardio-graphic RV assessment have been described, inclinical practice assessment of RV structure andfunction remains mostly qualitative. Nevertheless,numerous studies have recently emphasized theimportance of RV function in the prognosis ofa variety of cardio-pulmonary diseases suggestingthat more routine quantication of RV functionis warranted under most clinical circumstances.

Compared to the left ventricle, the right ven-tricle is a thin-walled structure under normalconditions. The normal right ventricle is accus-

tomed to a low pulmonary resistance and hencelow afterload; thus, normal RV pressure is low andright ventricular compliance high. The right ven-tricle is therefore sensitive to changes in after-load, and alterations in RV size and function areindicators of increased pulmonary vascular resis-tance and load transmitted from the left-sidedchambers. Elevations in RV afterload in adults aremanifested acutely by RV dilatation and chroni-cally by concentric RV hypertrophy. In addition,intrinsic RV abnormalities, such as infarction or RVdysplasia 82 can cause RV dilatation or reduced RVwall thickness. Thus, assessment of RV size andwall thickness is integral to the assessment of RVfunction.

Right ventricular free wall thickness, normallyless than 0.5 cm, is measured using either M-modeor 2-D imaging. Although RV free wall thickness canbe assessed from the apical and parasternal long-axis views, the subcostal view measured at thepeak of the R wave at the level of the tricuspidvalve chordae tendinae provides less variationand closely co rr elates with RV peak systolic pres-sure ( Fig. 10). 75 Care must be taken to avoid over

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measurement due to the presence of epicardial fatdeposition as well as coarse trabeculations withinthe right ventricle.

Qualitative assessment of RV size is easilyaccomplished from the apical four-chamber view(Fig. 11). In this view, RV area or mid cavity diam-eter should be smaller than that of the left ventri-cle. In cases of moderate enlargement, the RVcavity area is similar to that of the LV and it mayshare the apex of the heart. As RV dilation prog-resses, the cavity area will exceed that of the LVand the RV will be apex forming. Quantitativeassessment of RV size is also best performed inthe apical four-chamber view. Care must be takento obtain a true non-foreshortened apical four-chamber view, oriented to obtain the maximum

RV dimension, prior to making these measure-ments. Measurement of the mid-cavity and basalRV diameter in the apical four-chamber view atend-diastole is a simple method to quantify RVsize (Fig. 11). In addition, RV longitudinal diameter

can be measured from this view. Table 7 providesnormal RV dimensions from the apical four-cham-ber view. 76,80,83

Right ventricular size may be assessed may beassessed with TEE in the mid-esophageal four-chamber view ( Fig. 12). The mid-esophagealfour- chamber view, which generally parallels

what is obtainable from the apical four-chamber view, should originate at the mid-left atrial leveland pass through the LV apex with the multiplaneangle adjusted to maximize the tricuspid annulusdiameter, usually between 10 and 20 degrees.

Right ventricular systolic function is generallyestimated qualitatively in clinical practice. Whenthe evaluation is based on a qualitative assess-ment, the displacement of the tricuspid annulusshould be observed. In systole, the tricuspidannulus will normally descend toward the apex1.5 e 2.0 cm. Tricuspid annular excursion of lessthan 1.5 cm has been associated with poor pr ogno-sis in a variety of cardiovascular diseases. 84 Al-though a number of techniques exist for accuratequantitation, direct calculation of RV volumesand ejection fraction remains problematic giventhe complex geometry of the right ventricle andthe lack of standard methods for assessing RVvolumes. Nevertheless, a number of echocardio-graphic techniques may be used to assess RV func-tion. Right ventricular fractional area change (FAC)measured in the apical four-chamber view is a sim-ple method for assessment of RV function that hascorrelated with RV ejection fractions measured by

MRI (r 0.88) and has been relat ed to outcome ina number of disease states. 81,85 Normal RV areasand fractional area changes are shown in Table 8 .Additional assessment of the RV systolic functionincludes tissue imaging of tricuspid annular

Figure 10 Methods of measuring right ventricular wallthickness (arrows) from an M-mode echo (left) and asubcostal transthoracic echo (right).

Figure 11 Mid right-ventricular diameter measured in the apical four-chamber view at level of left ventricular papillary muscles.



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velocity or right ventric ular index of myocardialperformance (Tei Index). 86

The RV outow tract (RVOT) extends from theanterosuperior aspect of the right ventricle to the

pulmonary artery, and includes the pulmonaryvalve. It is best imaged from the parasternallong-axis view angled superiorly, and the para-sternal short-axis at the base of the heart. It canadditionally be imaged from the subcostal long andtransverse windows as well as the apical window.Measurement of the RV outow tract is mostaccurate from the parasternal short-axis ( Fig. 13)just proximal to the pulmonary valve . Mean RVOTmeasurements are shown in Table 7 . 75 With TEE,the mid-esophageal RV inow-outow view usuallyprovides the best image of the RVOT just proximalto the pulmonary valve ( Fig. 14).

Quantication of LA/RA size

The left atrium (LA) fullls three major physiologicroles that impact on LV lling and performance.

The left atrium acts as a contractile pump thatdelivers 15 e 30% of the LV lling, as a reservoir thatcollects pulmonary venous return during ventricu-lar systole and as a conduit for the passage of

stored blood from t he LA to the LV during earlyventricular diastole. 87 Increased left atrial size isassociat ed with adverse cardiovascular outcom-es. 88 e 90 An increase in atrial size most commonlyis related to increased wall tension due to in-creased lling pressure. 91,92 Although increasedlling volumes can cause an increase in LA size,the adverse outcomes associated with increaseddimension and volume are more strongly associ-ated with increased lling pressure. Relationshipsexist between increased left atrial size a nd th e in-cidence of atrial brillation and st roke, 93 e 101 riskof overall mortality after MI, 102,103 and the risk ofdeath and hospit alizati on in subjects with dilatedcardiomyopathy. 104 e 108 LA enlargement is a marker of both the severity and chronicity of diastolicdysfunctio n and magnitude of LA pressureelevation. 88,91,92

Table 7 Reference limits and partition values of right ventricular and pulmonary artery size 76

Referencerange

Mildlyabnormal

Moderatelyabnormal

Severelyabnormal

RV dimensionsBasal RV diameter (RVD#1) (cm) 2.0 e 2.8 2.9 e 3.3 3.4 e 3.8 3.9Mid RV diameter (RVD#2) (cm) 2.7e 3.3 3.4 e 3.7 3.8 e 4.1 4.2Base-to-apex length (RVD#3) (cm) 7.1 e 7.9 8.0 e 8.5 8.6 e 9.1 9.2

RVOT diametersAbove aortic valve (RVOT#1) (cm) 2.5 e 2.9 3.0 e 3.2 3.3 e 3.5 3.6Above pulmonic valve (RVOT#2) (cm) 1.7 e 2.3 2.4 e 2.7 2.8 e 3.1 3.2

PA diameter Below pulmonic valve (PA#1) (cm) 1.5 e 2.1 2.2 e 2.5 2.6 e 2.9 3.0

Figure 12 Transesophageal echo measurements of right ventricular diameters from the mid-esophageal four-chamber view, best imaged after optimizing the maximum obtainable RV size by varying angles from approximately0e 20 degrees.

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The LA size is measured at the end-ventricular systole when the LA chamber is at its greatestdimension. While recording images for computingLA volume, care should be taken to avoid fore-shortening of the LA. The base of the LA should beat its largest size indicating that the imaging planepasses through the maximal short-axis area. TheLA length should also be maximized ensuringalignment along the true long-axis of the LA.

When performing planimetry the LA, the conu-ences of the pulmonary veins and LA appendageshould be excluded.

With TEE, the LA frequently cannot t in itsentirety into the image sector. Measurements of LAvolume from this approach cannot be reliablyperformed however; LA dimension can be

estimated combining measurements from differ-ent imaging planes.

LA linear dimension

The LA can be visualized from multiple echocar-diographic views from which several potential LAdimensions can be measured. However, the largevolume of prior clinical and research work used the

M-mode or 2-D derived anteroposterior (AP) linear dimension obtained from the parasternal long-axisview making this the standard for linear LAmeasurement ( Fig. 15). 93,95,96,98,104,105 The con-vention for M-mode measurement is to measurefrom the leading edge of the posterior aortic wallto the leading edge of the posterior LA wall.

Table 8 Referenc e limits and partition values of right ventricular size and function as measured in the apicalfour-chamber view 80

Referencerange

Mildlyabnormal

Moderatelyabnormal

Severelyabnormal

RV diastolic area (cm 2) 11e 28 29e 32 33e 37 38RV systolic area (cm 2) 7.5 e 16 17e 19 20e 22 23RV fractional area change (%) 32 e 60 25e 31 18e 24 17

Figure 13 Measurement of the right ventricular outow tract diameter at the subpulmonary region (RVOT1) and atthe pulmonic valve annulus (RVOT2), in the mid-esophageal aortic valve short axis view, using a multiplane angle ofapproximately 45 e 70 degrees.



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However, to avoid the variable extent of spacebetween the LA and aortic root, the trailing edgeof the posterior aortic is recommended.

Although these linear measurements have beenshown to correlate with angiographic measure-ments and have been widely used in clinicalpractice and resear ch, they inaccurately representtrue LA size. 109,110 Evaluation of the LA in the APdimension assumes that a consistent relationshipis maintained between the AP dimension and allother LA dimensions a s the a trium enlarges, whichis often not the case. 111,112 Expansion of the leftatrium in the AP dimension may be constrainedby the thoracic cavity between the sternumand the spine. Predominant enlargement in thesuperior-inferior and medial-lateral dimensionswill alter LA geometry such that the AP dimension

may not be representative of LA size. For thesereasons, AP linear dimensions of the left atriumas the sole measure of left atrial size may be mis-leading and should be accompanied by left atrialvolume determination in both clinical practiceand research.

LA volume measurements

When LA size is measured in clinical practice,volume determinations are preferred over linear dimensions because they allow accurate assess-ment of the asymmetric remodeling of the LAchamber. 111 In addition, the strength of therelationship between cardiovascular disease isstrong er fo r LA volume than for LA linear dimen-sions. 97,113 Echocardiographic measures of LA vol-ume have been compared with cine-computedtomograp hy, bipla ne contrast ventriculographyand MRI.109,114 e 116 These studies have showneither good agreement or a tendency for echocar-diographic measurements to underestimate com-parative LA volumes.

The simplest method for estimating LA volume isthe cube formula, which assumes that the LAvolume is that of a sphere with a diameter equalto the LA antero-posterior dimension. However,this method has pr oven to be inferior to other volume techniques. 109,111,117 Left atrial volumesare best calculate d using either an ellipsoid m odelor Simpsons rule. 88,89,97,101,102,109 e 111,115 e 117

The ellipsoid model assumes that the LA can beadequately represented as a prolate ellipse witha volume of 4 p /3( L/2)( D1 /2)( D2 /2), where L is thelong-axis (ellipsoid) and D1 and D2 are orthogonalshort-axis dimensions. LA volume can be estimatedusing this biplane dimension-length formula bysubstituting the LA antero-posterior diameter acquired from the parasternal long-axis as D1 , LAmedial-lateral dimension from the parasternal

short-axis as D2 and th e LA long-axis from the apicalfour-chamber for L. 117 e 119 Simplied methodsusing non-orthogonal linear measurements for

Figure 14 Measurement of the right ventricular outow tract at the pulmonic valve annulus (RVOT2), and at andmain pulmonary artery from the midesophageal RV inow-outow view.

Figure 15 Measurement of left atrial diameter (LAD)from M-mode, guided by a parasternal short axis image(upper right) at the level of the aortic valve. This linear method is not recommended.

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estimation of LA volume have been proposed. 113

Volume determined using linear dimensions isvery dependent on careful selection of the loca-tion and direction of the minor axis dimensionsand has be en shown to signicantly underestimateLA volume.117

In order to estimate the LA minor axis dimension

of the ellipsoid more reliably, the long-axis LA areascan be traced and a composite dimension derived.This dimension takes into account the entire LAborder, rather than a single linear measurement.When long-axis-area is substituted for minor axisdimension, the biplane area e length formula isused: 8( A1)( A2)/3 p (L), where A1 and A2 representthe maximal planimetered LA area acquired fromthe apical four- and two-chamber-views, respec-tively. The length ( L) remains the LA long-axislength determined as the distance of the perpen-dicular line measured from the middle of the planeof the mitral annulus to the superior aspect of theleft atrium ( Fig. 16). In the area e length formulathe length ( L) is measured in both the four- andtwo-chamber views and the shortest of these twoL measurements is used in the formula.

The area e length formula can be computed froma single plane, typically the apical four-chamber,by assuming A1 A2, such that volume 8( A1)2/3p (L). 120 However, this method makes geometricassumptions that may be inaccurate. In older sub-jects the diaphragm lifts the cardiac apex upwardwhich increases the angle between ventricle and

atrium. Thus the apical four-chamber view willcommonly intersect the atria tangentially in older subjects and result in underestimation of volumeusing a single plane technique. Since the majorityof prior research and clinical studies have used thebiplane area e length formula, it is the recommen-ded ellipsoid method ( Figs. 15 and 16 ).

LA volume may also be measured using Simpsonsrule, similar to its application for LV measure-ments, which states that the volume of a geomet-rical gure can be calculated from the sum of thevolumes of smaller gures of similar shape. Mostcommonly, Simpsons algorithm divides the LA intoa series of stacked oval disks whose height is h andwhose orthogonal minor and major axes are D1 andD2 (method of disks). The volume of the entireleft atrium can be derived from the sum of the

Figure 16 Measurement of left atrial volume from the area e length method using the apical four-chamber (A4C) andapical two-chamber (A2C) views at ventricular end-systole (maximum LA size). The length ( L) is measured from theback wall to the line across the hinge points of the mitral valve. The shorter ( L) from either the A4C or A2C isused in the equation.



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volume of the individual disks. Volume p /4(h)P(D1)(D2). The formula is integrated with theaid of a computer and the calculated volumeprovided by the software package online ( Fig. 17).

The use of the Simpsons method in this wayrequires the input of biplane LA planimetry toderive the diameters. Optimal contours should be

obtained orthogonally around the long-axis of theleft atrium using TTE apical views. Care should betaken to exclude the pulmonary veins from the LAtracing. The inferior border should be representedby the plane of the mitral annulus. A single planemethod of disks could be used to estimate LAvolume by assumi ng the stacked disks are circular V p /4( h)P(D1). 2 However, as noted above, thismakes the assumption that the LA width in the api-cal two- and four-chamber are identical, which isoften not the case and therefore this formula isnot preferred.

Three-dimensional echocardiography shouldprovide the most accurate evaluation of LA volumeand has shown promise, however to date noconsensus exists on the specic method that shouldbe used for data acquisition and there is nocomparison with established normal values. 121 e 123

Normal values of LA measurements

The non-indexed LA linear measurements aretaken from a Framingham Heart Study cohort of

1099 subjects between the ages of 20 and45 years old who were not obese, were of averageheight and were without cardiovascular disease(Table 9 ). 11 Slightly higher values have beenreported in a cohort of 767 subjects withoutcardiovascular disease in whic h obesity and heightwere not exclusion criteria. 113 Both body size

and aging have been noted to inuence LAsize. 10,87,113 There are also gender differences inLA size, however, these are nearly com pletely ac-counted for by variation in body size. 87,113,120,124

The inuence of subject size on LA size is typicallycorrected by indexing to some measure of bodysize. In fact, from childhood on war d the indexedatrial volume changes very little. 125 Several index-ing methods have been proposed, such as height,weight, es tima ted lean body mass and body sur-face area. 10,113 The most commonly used conven-tion, and that recommended by this committee,is indexing LA size by dividing by body surfacearea.

Normal indexed LA volume has been determinedusing the preferred biplane techniques (area elength or method of disks) in a number of studiesinvolving several hund red patients to be22 G 6 ml/m 2 . 88,120,126,127 Absolute LA volume hasalso been reported however in clinical practiceindexing to body surface area accounts for varia-tions in body size and should therefore be used.As cardiac risk and LA size are closely linked,

Figure 17 Measurement of left atrial volume from the biplane method of discs (modied Simpsons rule), using theapical four-chamber (A4C) and apical two-chamber (A2C) views at ventricular end-systole (maximum LA size).

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more importantly than simply characterizing thedegree of LA enlargement, normal referencevalues for LA volume allow prediction of cardiacrisk. There are now multiple peer reviewed arti-cles which validate the progressive increase inrisk associated with having LA volumes greater than these normative values. 89,97,99 e 103,106 e 108,128

Consequently, indexed LA volume measurementsshould become a routine laboratory measure sinceit reects the burden and chronicity of elevated LVlling pressure and is a strong predictor ofoutcome.

Right atrium

Much less research and clinical data are availableon quantifying right atrial size. Although the RAcan be assessed from many different views, quan-tication of RA size is most commonly performedfrom the apical four-chamber view. The minor axisdimension should be taken in a plane perpendicu-lar to the long-axis of the RA and extends from thelateral border of the RA to the interatrial septum.Normative value s for the RA minor axis are shownin Table 9 . 80,129 Although RA dimension may varyby gender, no separate reference values for maleand females can be recommended at this time.

Although, limited data are available for RAvolumes, assessment of RA volumes would bemore robust and accurate for determination ofRA size than linear dimensions. As there are nostandard orthogonal RA views to use an apical

biplane calculation, the single plane area e lengthand method of discs formulae have been applied toRA volume determination in several small stud-ies. 120,130,131 We believe there is too little peer re-viewed validated literature to recommend normalRA volumetric values at this time. However, lim-ited data on small number of normal subjectsrevealed that indexed RA volumes are similar toLA normal values in men (21 m l/ m2) but appear to be slightly smaller in women. 120

Quantication of the aorta and IVC

Aortic measurements

Recordings should be made from the parasternallong-axis acoustic window to visualize the aorticroot and proximal ascending aorta. Two-dimen-sional images should be used to visualize the LVoutow tract and the aortic root should be re-corded in different views in varying intercostalspaces and at different distances from the leftsternal border. Right parasternal views, recorded

T a b l e 9

R e f e r e n c e l i m i t s a n d p a r t i t i o n v a l u e s f o r l e f t a t r i a l d i m e n s i o n s / v o l u m e s

W o m e n

M e n

R e f e r e n c e

R a n g e

M i l d l y

A b n o r m a l

M o d e r a t e l y

A b n o r m a l

S e v e r e l y

A b n o r m a l

R e f e r e n c e

R a n g e

M i l d l y

A b n o r m a l

M o d e

r a t e l y

A b n o r m a l

S e v e r e l y

A b n o r m a l

A t r i a l d i m e n s i o n s

L A d i a m e t e r ( c m )

2 . 7 e 3 . 8

3 . 9 e 4

. 2

4 . 3 e 4 . 6

4 . 7

3 . 0 e 4 . 0

4 . 1 e 4 . 6

4 . 7 e 5 . 2

5 . 2

L A d i a m e t e r / B S A ( c m / m 2 )

1 . 5 e 2 . 3

2 . 4 e 2

. 6

2 . 7 e 2 . 9

3 . 0

1 . 5 e 2 . 3

2 . 4 e 2 . 6

2 . 7 e 2 . 9

3 . 0

R A m i n o r a x i s d i m e n s i o n ( c m )

2 . 9 e 4 . 5

4 . 6 e 4

. 9

5 . 0 e 5 . 4

5 . 5

2 . 9 e 4 . 5

4 . 6 e 4 . 9

5 . 0 e 5 . 4

5 . 5

R A m i n o r a x i s d i m e n s i o n / B S A ( c m / m 2 )

1 . 7 e 2 . 5

2 . 6 e 2

. 8

2 . 9 e 3 . 1

3 . 2

1 . 7 e 2 . 5

2 . 6 e 2 . 8

2 . 9 e 3 . 1

3 . 2

A t r i a l a r e a

L A a r e a ( c m

2 )

2 0

2 0 e 3

0

3 0 e

4 0

> 4 0

2 0

2 0 e

3 0

3 0 e

4 0

> 4 0

A t r i a l v o l u m e s

L A v o l u m e ( m l )

2 2 e

5 2

5 3 e 6

2

6 3 e

7 2

7 3

1 8 e

5 8

5 9 e

6 8

6 9 e

7 8

7 9

L A v o l u m e / B S A ( m l / m

2 )

2 2 G 6

2 9 e 3

3

3 4 e

3 9

4 0

2 2 G 6

2 9 e

3 3

3 4 e 3 9

4 0

V a l u e s i n b o l d a r e r e c o m m e n d e d a n d b e s t v a l i d a t e d

.



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with the patient in a right lateral decubitusposition are also useful. Measurements are usuallytaken at: (1) aortic valve annulus (hinge point ofaortic leaets); (2) the maximal diameter in thesinuses of Valsalva; and (3) sinotubular junction(transition between the sinuses of Valsalva and thetubular portion of the ascending aorta).

Views used for measurement should be thosethat show the largest diameter of the aortic root.When measuring the aortic diameter, it is partic-ularly important, to use the maximum obtainableshort-axis diameter measured perpendicular to thelong-axis of the vessel in that view. Some expertsfavor inner edge-to-inner edge techniques tomatch those used by other methods of imagingthe aorta, such as MRI and CT scanning. However the normative data for echocardiography wereobtained using the leading edge technique(Fig. 18). Advances in ultrasound instrumentationwhich have resulted in improved image resolutionshould minimize the difference between thesemeasurement methods.

Reliability of aortic root measurements bythis method yielded an intra-class correlationcoefcient of 0.79 ( p < 0.001) in a study of 183hypertensive patients (unpublished data). Two-dimensional aortic diameter measurements arepreferable to M-mode measurements, as cyclicmotion of the heart and resultant changes inM-mode cursor location relative to the maximumdiameter of the sinuses of Valsalva result insystematic underestimation (by w 2 mm) of aortic

diameter by M- mode in comparison to the 2-Daortic diameter. 132 The aortic annular diameter ismeasured between the hinge points of the aorticvalve leaets (inner edge e inner edge) in the para-sternal or apical long-axis views that reveal thelargest aortic annular diameter with color ow

mapping to clarify tissue e blood interfaces ifnecessary. 132

The thoracic aorta can be better imaged usingTEE than, as most of it is in the near eld of thetransducer. The ascending aorta can be seen inlong-axis, using the mid-esophageal aortic valvelong-axis view at about 130 degrees and the mid-

esophageal ascending aorta long-axis view. Theshort-axis view of the ascending aorta is obtainedusing the mid-esophageal views at about 45 de-grees. For measurements of the descending aorta,short-axis views at about 0 degrees, and long-axisviews at about 90 degrees, can be recorded fromthe level of the diaphragm up to the aortic arch(Fig. 19). The arch itself and origins of two of thegreat vessels can be seen in most patients. Thereis a blind spot in the upper ascending aortaand the proximal arch that is not seen by TEEdue to the interposed tracheal bifurcation.

Identication of aortic root dilatation

Aortic root diameter at the sinuses of Valsalva isrelated most strongly to body surface area andage. Therefore, body surface area may be used topredict aortic root diameter in three age-strata:< 20 years, 20e 40 and > 40 years, by publishedequations. 132 Aortic root dilatation at the sinusesof Valsalva is dened as an aortic root diameter above the upper limit of the 95% condence inter-val of the distribution in a large reference popula-tion. 132 Aortic dilatation can be easily detected by

plotting observed aortic root diameter versus bodysurface a re a on previously-published nomograms(Fig. 20). 132 Aortic dilatation is strongly associatedwith the presence and progression of aortic regur-gitation 133 and with the occurrence of aorticdissection. 134 The presence of hypertension

Figure 18 Measurement of aortic root diameters at the aortic valve annulus (AV ann) level, the sinuses of Valsalva(Sinus Val), and the Sino-tubular junction (ST J n) from the mid-esophageal long axis view of the aortic valve, usu-ally at an angle of approximately 110 e 150 degrees. The annulus is measured by convention at the base of the aorticleaets. Although leading edge to leading edge technique is demonstrated for the sinuses of Valsalva and sinotubular junction, some prefer the inner edge to inner edge method (see text for further discussion).

102 R.M. Lang et al.


25/30

appears to have minimal impact o n aort ic rootdiameter at the sinuses of Valsalva 133,135 but isassociated with enlargement of more distal aorticsegments. 135

Evaluation of the inferior vena cava

Examination of the inferior vena cava (IVC) fromthe subcostal view should be included as part ofthe routine TTE examination. It is generally agreedthat the diameter of the inferior vena cava should

be measured with the patient in the left decubitusposition at 1.0 e 2.0 cm from the junction with theright atrium, using the long-axis view. For accu-racy, this measurement should be made perpen-dicular to the IVC long-axis. The diameter of the

inferior vena cava decreases in response to inspira-tion when the negative intrathoracic pressureleads to an increase in right ventricular llingfrom the systemic veins. The diameter of the IVCand the percent decrease in the diameter duringinspiration correlate with right atrial pressure.The relation ship has been called the collapsibil-ity index. 136 Evaluation of the inspiratory re-sponse often requires a brief sniff as normalinspiration may not elicit this response.

The normal IVC diameter is < 1.7 cm. There is

a 50% decrease in the diameter when the rightatrial pressure is normal (0 e 5 mmHg). A dilatedIVC (> 1.7 cm) with normal inspiratory collapse( 50%) is suggestive of a mildly elevated RA pres-sure (6 e 10 mmHg). When the inspiratory collapse

Figure 19 Measurement of aortic root diameter at the sinuses of Valsava from 2-D parasternal long-axis image.Although leading edge to leading edge technique is shown, some prefer the inner edge to inner edge method(see text for further discussion).

Figure 20 95% condence intervals for aortic root diameter at the sinuses of Valsalva based on b ody surface area in:children and adolescents (A), adults aged 20 e 39 years (B), and adults aged 40 years or more (C). 132



26/30

is < 50%, the RA pressure is usually between 10 and15 mmHg. Finally, a dilated IVC without any col-lapse suggests a markedly increased RA pressureof > 15 mmHg. In contrast, a small IVC (usually< 1.2 cm) with spontaneous collapse often is seenin the pr esence of intravascular volumedepletion. 137

There are several additional conditions to beconsidered in evaluating the inferior vena cava.Athletes have been shown to have dilated inferior vena cav ae with normal collapsibility index. Stud-ies 137,138 have found that the mean IVC diameter inathletes was 2.31 G 0.46 compared to 1.14 G 0.13in aged-matched normals. The highest diameterswere seen in highly trained swimmers.

One study showed that a dilated IVC in themechanically ventilated patient did not alwaysindicate a high right atrial pressure. However,a small IVC (< 1.2 cm) had a 100% specicity for a RA pr essure of less than 10 mmHg with a low sen-sitivity. 139 A more recent study suggested thatthere was a better correlation when the IVC diam-eter was measured at end-expiration and end-diastole using M-mode echocardiography. 140

The use of the inferior vena cava size anddynamics is encouraged for estimation of the rightatrial pressure. This estimate should be used inestimation of the pulmonary artery pressure basedon the tricuspid regurgitant jet velocity.

Acknowledgments

The authors wish to thank Harvey Feigenbaum,MD, and Nelson B. Schiller for their careful reviewand thoughtful comments.

References

1. Sahn DJ, DeMaria A, Kisslo J, Weyman A. Recommenda-tions regarding quantitation in M-mode echocardiography:results of a survey of echocardiographic measurements.Circulation 1978;58 :1072e 83.

2. Schiller NB, Shah PM, Crawford M, DeMaria A, Devereux R,Feigenbaum H, et al. Recommendations for quantitationof the left ventricle by two-dimensional echocardiography.American Society of Echocardiography Committee on Stan-dards, Subcommittee on Quantitation of Two-DimensionalEchocardiograms. J Am Soc Echocardiogr 1989;2 :358e 67.

3. Hirata K, Watanabe H, Beppu S, Muro T, Teragaki M,Yoshiyama M, et al. Pitfalls of echocardiographic measure-ment in tissue harmonic imaging: in vitro and in vivo study. J Am Soc Echocardiogr 2002;15 :1038 e 44.

4. McGaviganAD, DunnFG, Goodeld NE. Secondaryharmonicimaging overestimates left ventricular mass compared tofundamental echocardiography. Eur J Echocardiogr 2003;4 :178e 81.

5. FeigenbaumH, Armstrong W,RyanT. Feigenbaumsechocar-diography . 6th ed. Philadelphia (PA): Lippincott, Williamsand Wilkins; 2005.

6. Mulvagh SL, DeMaria AN, Feinstein SB, Burns PN,Kaul S, Miller JG, et al. Contrast echocardiography:current and future applications. J Am Soc Echocardiogr 2000; 13 :331e 42.

7. Nahar T, Croft L, Shapiro R, Fruchtman S, Diamond J,Henzlova M, et al. Comparison of four echocardiographictechniques for measuring left ventricular ejection frac-tion. Am J Cardiol 2000;86 :1358e 62.

8. Colombo PC, Municino A, Brofferio A, Kholdarova L,Nanna M, Ilercil A, et al. Cross-sectional multiplane trans-esophageal echocardiographic measurements: comparisonwith standard transthoracic values obtained in the samesetting. Echocardiography 2002;19 :383e 90.

9. Hozumi T, Shakudo M, Shah PM. Quantitation of left ven-tricular volumes and ejection fraction by biplane transeso-phageal echocardiography. Am J Cardiol 1993;72 :356e 9.

10. Vasan RS, Levy D, Larson MG, Benjamin EJ. Interpretationof echocardiographic measurements: a call for standardi-zation. Am Heart J 2000;139 :412e 22.

11. Vasan RS, Larson MG, Levy D, Evans JC, Benjamin EJ.Distribution and categorization of echocardiographic mea-surements in relation to reference limits: the FraminghamHeart Study: formulation of a height- and sex-specicclassication and its prospective validation. Circulation1997; 96 :1863 e 73.

12. Devereux RB, Roman MJ. Evaluation of cardiac and vascu-lar structure by echocardiography and other noninvasivetechniq

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