The Egyptian Heart Journal (2013) xxx, xxx–xxx

Egyptian Society of Cardiology

The Egyptian Heart Journal

www.elsevier.com/locate/ehjwww.sciencedirect.com

Echocardiographic assessment of left ventricular mechanical

dyssynchrony – A practical approach

Ahmed M. El Missiri *,1

Cardiology Department, Ain Shams University, Egypt

Received 8 June 2013; accepted 6 August 2013

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KEYWORDS

Ventricular dyssynchrony;

Echocardiography;

Tissue Doppler;

Heart failure;

Three-dimensional

echocardiography

Address: Cardiology Depar

niversity, Abbassia, Cairo, E

-mail address: amissiri@me

Accredited by the European

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Abstract Echocardiographic assessment of left ventricular mechanical dyssynchrony (LVMD)

received great interest with the appearance of Cardiac resynchronization therapy ever since the first

successful implants. Recent guidelines still keep QRS duration as the main selection criterion for

diagnosing the presence of LVMD. However, measurement of QRS duration, which is an electrical

phenomenon, seems to provide only a crude estimate on myocardial activation and is poorly cor-

related with the presence of LVMD. Echocardiography seems to be a more reliable tool for cor-

rectly identifying candidates for CRT and thus reducing the number of clinical non-responders.

Recently LMVD was found to be associated with other cardiac and noncardiac diseases. Therefore,

echocardiographic assessment of LVMD will always remain of importance.

The aim of this article is to present a simplified, step-wise approach for the assessment of LVMD

which can be easily followed and performed by echocardiographers to produce reliable, reproduc-

ible results for the assessment of LVMD.ª 2013 Production and hosting by Elsevier B.V. on behalf of Egyptian Society of Cardiology.

Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 002. Aim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 003. Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00

culty of Medicine, Ain Shams

.: +20 100 161 4717.

.eg.

tion of Echocardiography for

cardiography (2012–2017)

tian Society of Cardiology.

g by Elsevier

ng by Elsevier B.V. on behalf of Egyptian Society of Cardiology.

02

l Missiri AM Echocardiographic assessment of left ventricular mechanical dyssynchrony – Art J (2013), http://dx.doi.org/10.1016/j.ehj.2013.08.002

2 A.M. El Missiri

4. Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00

4.1. M-mode measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 004.2. Pulsed wave Doppler measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 004.3. TDI measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00

4.3.1. Loop acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 004.3.2. Analysis of acquired loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00

4.4. Real-time three dimensional echocardiography (RT3DE) measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 004.4.1. LV full volume acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00

4.4.2. LV full volume analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 005. Limitations of echocardiographic assessment of LVMD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 006. Summary and recommended indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00

Conflict of interest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00

1. Introduction

Echocardiography has played an essential role in Cardiac

resynchronization therapy (CRT) ever since the first successfulimplants whether it was for the estimation of left ventricularejection fraction (LVEF), LV volumes, grade of mitral regurgi-tation, etiology of heart failure (HF), or the assessment of left

ventricular mechanical dyssynchrony (LVMD). In recentguidelines, QRS duration still remains the main selection crite-rion for diagnosing the presence of LVMD in clinical practice.

This is mainly because the large prospective, randomized trialssolely relied on the QRS width as the only marker for dyssyn-chrony.1 However, measurement of QRS duration, which is an

electrical phenomenon, seems to provide only a crude estimateon myocardial activation and is poorly correlated with thepresence of mechanical dyssynchrony.2

In spite of the promising results of the randomized clinical

trials, analysis of individual responses revealed that 20–30% ofpatients did not respond to CRT.3

In contrast, echocardiography allows the severity of

mechanical dyssynchrony and its impact on cardiac hemody-namics to be assessed in a quantitative manner. It thereforeseems to be a more reliable tool for correctly identifying can-

didates for CRT and thus reducing the number of clinicalnon-responders.4

At first glance, echocardiographic assessment of LVMD

seems to be time consuming, requiring special expertise, andthe optimal protocol for dyssynchrony assessment has notyet been defined. However, important information about thepresence and severity of dyssynchrony can be obtained from

conventional echocardiographic techniques and dyssynchronyassessment can be easily integrated into daily routine practice.1

The role of echocardiography in assessing LVMD in CRT

patients remains controversial to date. The Predictors of Re-sponse to Cardiac Resynchronization Therapy (PROSPECT)trial examined the predictive value of many echocardiographic

parameters of dyssynchrony (Doppler, M-mode, tissue Dopp-ler imaging [TDI], and delayed longitudinal contraction) onLV reverse remodeling and composite clinical score. It con-

cluded that given the modest sensitivity and specificity in thismulticenter setting despite training and central analysis, nosingle echocardiographic measure of dyssynchrony may berecommended to improve patient selection for CRT beyond

current guidelines.5 However, another study from three experi-enced centers in dyssynchrony assessment reproduced a

Please cite this article in press as: El Missiri AM Echocardiographpractical approach, The Egypt Heart J (2013), http://dx.doi.org/1

positive role for TDI. In that study, three parameters derivedfrom 12 LV segments and septal-to-lateral wall delay predictedLV reverse remodeling and improvement of LV ejection

fraction.6

Three different levels of dyssynchrony can be distinguishedby echocardiography: (1) Atrioventricular dyssynchrony:

delayed ventricular activation in relation to the atria owing toprolongation of the PR interval. (2) Interventricular dyssynchro-ny: delayed onset and end of LV systole due to delayed LV elec-

trical activation in comparison to the RV. (3) Intraventriculardyssynchrony:delayed activation of someLV segmentswith pro-longed contraction after aortic valve closure.7

The first two levels can be easily identified by conventional

echocardiography. Tissue Doppler tissue imaging (TDI) iscurrently regarded as the most sensitive technique for quanti-fication of intraventricular dyssynchrony.1

2. Aim

The aim of this article is to present a simplified, step-wise

approach for the assessment of LVMD which can be easilyfollowed and performed by echocardiographers to producereliable, reproducible results for the assessment of LVMD.

3. Review

Echocardiographic measurements of LVMD that will be

reviewed in detail in this article are:

1. Septal-to-posterior wall motion delay (SPWMD).

2. Inter-ventricular mechanical delay (IVMD).3. Tissue Doppler tissue imaging indices:

a. Mechanical dyssynchrony index/Yu index.b. Maximal difference in Ts.

c. Basal septal-to-lateral wall Ts.4. Systolic dyssynchrony index (SDI-16).

Table 1 lists all these measurements of LVMD with theirnormal values, cut-off values for the presence of LVMD,advantages and disadvantages.

All measurements of LVMD listed in this article are inconcordance with the recommendations for performance andreporting of the American Society of Echocardiography

Dyssynchrony Writing Group.11

ic assessment of left ventricular mechanical dyssynchrony – A0.1016/j.ehj.2013.08.002

Table 1 Echocardiographic measurements of LVMD.

Index Method Normal value Cut-off value Advantages Disadvantages

M-mode measurements

Septal to posterior wall

delay (SPWMD)10M-mode color TDI

(parasternal short axis,

mid-LV view)

<40 ms P130 ms * Widely available

* Rapidly applied

* No advanced techni-

cal requirements

* Largely affected by

passive motion or

tethering

* Difficulties with seg-

mental akinesis

Doppler measurements

Inter-ventricular

mechanical delay

(IVMD)11

Routine pulsed wave

Doppler (RVOT and

LVOT views)

<20 ms P40 ms * Widely available

* No advanced techni-

cal requirements

* Highly reproducible

* Nonspecific

* Affected by LV and

RV function

Tissue Doppler imaging (TDI) measurements

Basal septal-to-lateral

wall delay12Color TDI Ts (apical

views)

<50 ms P65 ms * Rapidly applied

* Offline analysis is

possible

* Affected by passive

motion tethering

Maximum difference in

Ts (12 sites)16Color DTI Ts (apical

views)

<90 ms P100 ms * More complete detec-

tion of longitudinal

dyssynchrony

* Offline analysis is

possible

* Affected by passive

motion tethering

Ts-SD/Dyssynchrony

index/Yu index14Color DTI 12 segment

SD of Ts (apical views)

<30 ms P33 ms * More complete dete-

cion of longitudinal

dyssynchrony

* Offline analysis is

possible

* Affected by passive

motion tethering

Real-time three-dimensional echocardiography (RT3DE) measurements

SDI-1615 RT3DE (apical view) <5% P8.3% * Accurate volume

measurements

* Quantitative and

qualitative

* Assess dyssynchrony

simultaneously in the

same loop

* Low spatial resolution

* Learning curve

* Technically

demanding.

* Time-consuming for

offline analysis

Echocardiographic assessment of left ventricular mechanical dyssynchrony – A practical approach 3

4. Preparation

The echocardiographer should start by properly preparing

both the patient and the echocardiography machine in orderto enhance the quality of acquired images and loops which willfacilitate analysis later on. This is achieved by doing the

following:

1. Ensure proper connection of the machine-integrated elec-trocardiogram (ECG) cable to the patient with each lead

connected at the position recommended by the machine’smanufacturer. This will help generate proper QRS com-plexes which is important for analysis.

2. Perform the study with the patient in the left lateral decubi-tus position.

3. Patients whose breathing affects image quality may be asked

to hold their breath during image and loop acquisition.4. Sweep speed should be set to 50–100 mm/s for all time

interval measurements.

It is recommended not to perform echocardiographicassessment of LVMD for the following groups of patients:

Please cite this article in press as: El Missiri AM Echocardiographpractical approach, The Egypt Heart J (2013), http://dx.doi.org/1

1. Patients with atrial fibrillation or other atrial arrhythmias.12

2. Patients with decompensated heart failure.3. Poorly echogenic patients in whom acquiring good quality

images and loops is not possible.

4. Patients with a previously implanted working pacemaker.5. Patients with recent acute coronary syndromes.6. Patients with a possibly reversible cause of heart failure.

4.1. M-mode measurements

Septal-to-posterior wall-motion delay (SPWMD) measured byM-mode color-TDI is technically the simplest approach to

quantify LVMD. The addition of color TDI to M-mode aidsin identifying the transition from inward to outward motionin the septum and posterior wall.11

Steps:

1. M-mode color-TDI echocardiography is done from the

parasternal short-axis view at the level of the papillarymuscles to calculate the SPWMD.

2. SPWMD is measured from the point of change in motion

direction in the anterior septum (where color changes fromblue to red) to that in the posterior wall (where colorchanges from red to blue) as in Fig. 1.1

ic assessment of left ventricular mechanical dyssynchrony – A0.1016/j.ehj.2013.08.002

Figure 1 M-mode color TDI.

Figure 2 Measurement of LVPEP.

4 A.M. El Missiri

3. SPWMD should not be measured when the anterior septumis akinetic or dyskinetic. Therefore it is not advocated to beused in isolation to quantify dyssynchrony, but may be con-

sidered as supplemental to other approaches in particular inpatients with ischemic cardiomyopathy.19

Normally SPWMD is less than 40 ms. The cut-off value ofgreater than or equal to 130 ms is a marker of LV dyssyn-chrony in patients with non-ischemic cardiomyopathy (sensi-

tivity 100% and specificity of 63%). Longer delays inSPWMD are associated with greater reverse remodeling afterCRT.13,20

4.2. Pulsed wave Doppler measurements

Under normal conditions, right ventricular (RV) and LV out-flow occur almost simultaneously and the interventricular

Please cite this article in press as: El Missiri AM Echocardiographpractical approach, The Egypt Heart J (2013), http://dx.doi.org/1

mechanical delay (IVMD) between the ventricles is close to

zero. IVMD is defined as the difference between the LV andRV pre-ejection periods (LVPEP, RVPEP).

The IVMD correlates to QRS duration, it is normally less

than 20 ms and is typically increased to more than 40 ms in pa-tients with a QRS width of more than 150 ms.21

Steps:

1. Pulsed wave (PW) Doppler is applied along the aortic valvein the apical 5 chamber view.

2. LVPEP is measured as the time from the beginning of the

QRS complex to the beginning of the systolic flow acrossthe aortic valve (Fig. 2).11

3. The cut-off value is 140 ms.14

4. Pulsed wave (PW) Doppler is applied along the pulmonaryvalve in the parasternal short-axis view at the level of theaortic valve.

ic assessment of left ventricular mechanical dyssynchrony – A0.1016/j.ehj.2013.08.002

Figure 3 Measurement of RVPEP.

Echocardiographic assessment of left ventricular mechanical dyssynchrony – A practical approach 5

5. RVPEP is measured as the time from the beginning of the

QRS complex to the beginning of the systolic flow acrossthe pulmonary valve (Fig. 3).11

6. IVMD is calculated by subtracting RVPEP from LVPEP11

with a cut-off value of 40 ms (sensitivity 66% and specificity55%).14

4.3. TDI measurements

4.3.1. Loop acquisition

Intraventricular dyssynchrony is probably the most importantlevel of dyssynchrony evaluation. The most precise methodol-ogy for identification and quantification of the intraventricular

level of dyssynchrony is probably TDI.1

The 2D color-TDI cine loops of multiple beats can bestored digitally for offline analysis. This allows the comparison

of multiple segments from each view simultaneously and is amuch quicker way of assessing myocardial function and syn-chronicity. It also reduces the time for online image acquisitionand hence scanning time of the patient is reduced. Adequate

technical attention is mandatory, however, to obtain optimalimage quality that supports offline analysis.11

The mechanical dyssynchrony index (Ts-SD, Yu index) is

the standard deviation of the time-to-peak systolic velocity(Ts) at each of the twelve basal and mid segments of the LV(namely the septal, lateral, anterior, inferior, anteroseptal

and posterior segments at both basal and mid levels). It is nor-mally less than 30 ms and the most frequently used cut-off va-lue is 33 ms. This cut-off value has a sensitivity of 100% and

specificity of 78% in patients with QRS duration greater than150 ms, whereas, the sensitivity is 83% and specificity is 86%for patients with a borderline prolongation of QRS durationof 120–150 ms.17,22

Other TDI dyssynchrony indices are the maximal differencein Ts (normally less than 90 ms and with a cut-off value of100 ms)17,22 and the difference between the basal septal and

Please cite this article in press as: El Missiri AM Echocardiographpractical approach, The Egypt Heart J (2013), http://dx.doi.org/1

the basal lateral wall Ts (normally less than 50 ms and witha cut-off value of 65 ms).3

Steps:

The following steps should be performed to ensure the bestquality of the acquired loops1:

1. Color Doppler requires a high frame rate, preferably morethan 100 frames/s, and ideally more than 140 frames/s. Thiscan be achieved by reducing depth and sector width (ideally

both grayscale and Doppler sectors) and by choosing set-tings that favor temporal over spatial resolution. Usually,the image is optimized in the grayscale display before

switching to the color mode and acquiring images.Accordingly:

a. The ‘‘Depth’’ option should be adjusted so that theacquired loop includes only the LV from the apex

down to level of the mitral valve annulus.b. The ‘‘Angle’’ option should be adjusted so that the

narrowest possible sector with the opposing LV walls

clearly visualized could be acquired.c. Frame rate should be increased to the maximum

available for the corresponding sector width.

2. The ‘‘Tilt’’ option should be used when necessary so that

the region of interest (ROI) on the sampling cursor wouldbe tangential to the LV walls.

3. In patients with markedly dilated LV cavities and poorlyechogenic patients, it is suggested to acquire each wall sep-

arately with the sector narrowed to include only that wall.This increases frame rate and will provide proper velocitywaves on image analysis.

4. Color-coded TDI loops are obtained from each of the api-cal 4-chamber, apical 2-chamber and apical long-axis views.

5. It is recommended that each acquired loop consists of 3 car-

diac cycles (i.e. containing 4 QRS complexes, beginning justbefore the first and ending just after the last). These arethen stored to be available for offline analysis with the

available software.

ic assessment of left ventricular mechanical dyssynchrony – A0.1016/j.ehj.2013.08.002

Figure 4 Off-line analysis of the acquired 2-D color TDI image.

Figure 5 An acquired LV full volume.

6 A.M. El Missiri

6. For sufficient temporal matching, all acquisitions shouldhave similar heart rate and show the same electrocardio-graphic lead.

7. Care should be taken to avoid reverberation artifacts by

changing interrogation angle and transducer position,because such artifacts may affect TDI estimations over awide area.

8. The velocity scale should be set to a range that just avoidsaliasing in any region of the myocardium. Slowly scrollingthrough the image loop before storing allows recognition of

possible aliasing.9. Older imaging systems that store only color values in an

image should not be used unless post-processing is not

planned.

Please cite this article in press as: El Missiri AM Echocardiographpractical approach, The Egypt Heart J (2013), http://dx.doi.org/1

4.3.2. Analysis of acquired loops

Analysis software differs according to the manufacturer butthey are generally quite similar. The following steps help sim-plify the analysis procedure and provide both reliable and

reproducible results:

1. Some commercially available machines have the so-called

aortic valve opening (AVO) and aortic valve closure(AVC) event timing markers. These are marked ontrans-aortic pulsed wave (PW) Doppler flow images at thebeginning and end of systolic flow across the aortic valve

respectively. It is recommended to take AVO and AVC ofthree consecutive cardiac cycles. These are averaged bythe machine and stored.

ic assessment of left ventricular mechanical dyssynchrony – A0.1016/j.ehj.2013.08.002

Figure 6 Sample of software generated report.

Echocardiographic assessment of left ventricular mechanical dyssynchrony – A practical approach 7

2. AVO and AVC are automatically superimposed on the TDI

tracings later on during analysis. They identify the true ejec-tion phase.

3. If the AVO and AVC options are not available, the ejectionphase can be identified by making a note of the time from

the beginning of the QRS complex to the beginning and endof systolic flow across the aortic valve on PW Doppler flowimages respectively.

4. ROI are sized (a minimum of 5 · 10–7 · 15 mm) and placedin the basal and mid segments of opposing LV walls (4regions/view) to determine time-velocity plots.

5. Move the ROI up and down as well as sideways at each seg-ment to ensure that the generated myocardial velocity curvehas a consistent profile.

6. Time to peak systolic velocity (Ts) is measured as the timefrom the beginning of the QRS complex to the peak myo-cardial systolic velocity during the ejection phase (Fig. 4).

7. The following are solutions to some commonly faced prob-

lems during TDI analysis1:a. If there are multiple peaks in the ejection phase, the

highest peak is taken.

b. If there are two or more peaks in the ejection phasewith the same velocity, the earliest peak is taken.

c. If a segment has only a negative peak in the ejection

phase, or if a reliable myocardial velocity curve couldnot be generated, or if the velocity curve is noisywith verylow and inconsistent velocities, this particular segment isexcluded from the final calculations.Keeping in consider-

ation that only amaximumof 3 segments canbe excludedprovided that they are not from the same wall.

d. Velocity is not measured at the isovolumic contrac-

tion phase, isovolumic relaxation phase or duringpost-systolic shortening even if they intercept withthe AVO or AVC markers at a higher velocity than

the peak found within the ejection phase.

Please cite this article in press as: El Missiri AM Echocardiographpractical approach, The Egypt Heart J (2013), http://dx.doi.org/1

The following dyssynchrony indices are calculated: (a)

Mechanical dyssynchrony index (Ts-SD or Yu index), (b)Maximum difference in Ts, and (c) Difference between basal

septal and basal lateral wall Ts.

4.4. Real-time three dimensional echocardiography (RT3DE)

measurements

LV dyssynchrony in reality is a 3-dimensional phenomenon.23

In this regard, RT3DE is unique in that it allows simultaneousdyssynchrony comparison of all the myocardial segments

(including the apex) in the same heart beat.24

A dyssynchrony index has been devised by measuring thetime from the onset of the cardiac cycle (defined as the start

of the R wave) to the minimum systolic volume for each seg-ment, and then calculating the standard deviation (SD). Thesystolic dyssynchrony index (SDI) is the SD expressed as a per-centage of the duration of the entire cardiac cycle. Higher SDI

levels represent higher levels of dyssynchrony, and vice versa.SDI can be expressed as a percentage of the cardiac cyclerather than in milliseconds to allow comparisons between pa-

tients who have different heart rates.24

Steps24,25:

RT3DE LV full volume acquisition is performed from the

apical window, with the patient lying in the left lateral decubi-tus position. This is triggered by the R waves of four cardiaccycles taken during a single breath-hold in end-expiration.

The acquired full volume cine loop is digitally stored andtransmitted to commercially available workstation for analysis.

4.4.1. LV full volume acquisition

1. A standard 2-D apical 4-chamber view is obtained.2. The ‘‘Angle’’ option is used to ensure that the opposing LV

walls are included within the acquired cine loop.

ic assessment of left ventricular mechanical dyssynchrony – A0.1016/j.ehj.2013.08.002

8 A.M. El Missiri

3. The ‘‘4D’’ option is then selected and the depth option is

used to include only the LV cavity from the apex downto the mitral annulus.

4. Breath-hold in end-expiration should be demonstrated to

the patient and then the patient is asked to do it for 5 sec-onds during which the ‘‘Full volume’’ option is selected forLV full volume acquisition.

5. Acquired LV full volume cine loops are digitally stored and

transferred to the attached workstation for off-line analysis(Fig. 5).

4.4.2. LV full volume analysis

Analysis steps differ according to the manufacturer but they

generally follow the same steps.

1. Acquired LV full volumes are reviewed using commercially

available software. An LV full volume is rejected if theendocardial borders are not clearly delineated, or if thereis a large dropout in part of the LV walls that could not

be compensated for with the available tools in the software.These tools enable rotation of the three longitudinal planeswithin the acquired full volume in order to generate apical4-chamber, 2-chamber and apical long-axis views.

2. The software automatically generates the three standardapical views in both end-diastole and end-systole.

3. These can be further adjusted if found to be erroneous by

rotation of the three longitudinal planes.4. Once a satisfactory result is obtained semi-automated bor-

der detection is done for each view both at end-diastole

and end-systole.5. Border detection sensitivity could be increased or reduced if

necessary using the software.

6. Analysis options then automatically generate LVEF andvolumes as well as the systolic dyssynchronicity index(SDI-16): which is the standard deviation of the time-to-minimum systolic volume (Tmsv) calculated at each of

the sixteen segments of the LV normalized to the corre-sponding R-R interval (Fig. 6).24 This is normally less than5% with a cut-off value of 8.3%.18

5. Limitations of echocardiographic assessment of LVMD

1. The American Society of Echocardiography Dyssynchrony

Writing Group currently does not recommend that patientswho meet accepted criteria for CRT should have therapywithheld because of results of an echocardiographic Dopp-

ler dyssynchrony study.11

2. The American Society of Echocardiography DyssynchronyWriting Group advises that the dyssynchrony reportingshould not include a recommendation whether a patient

should undergo CRT, as this should be a clinical decisionon a case-by-case basis.11

6. Summary and recommended indications

1. Currently, after the Predictors of Response to CRT and the

Mayo Clinic studies, which support the indications in clin-ical guidelines, there is no definite role for the echocardio-graphic measurement of mechanical dyssynchrony to

indicate the need for CRT in patients with heart failure.

Please cite this article in press as: El Missiri AM Echocardiographpractical approach, The Egypt Heart J (2013), http://dx.doi.org/1

2. There is a potential role for dyssynchrony imaging in

patients with borderline QRS duration, in which this addi-tional information may help, and this methodology may aidin determining the site of latest mechanical activation which

can be taken into consideration by the CRT implantationteam.

3. Some recently published articles concluded that LVMDwas found to be associated with left ventricular diastolic

dysfunction,8 and with left atrial function in heart failurepatients.9 LVMD might also be an early manifestation ofcardiac involvement in sickle cell anemia, and is even pres-

ent in subjects with no known cardiac disease.10 Therefore,echocardiographic assessment of LVMD may play a futurerole in such patients.

Conflict of interest

None.

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544–9.

3. Bax JJ, Van der Wall EE, Schalij MJ. Cardiac resynchronization

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