Comparison of three-dimensional echocardiography and speckle tracking echocardiography in quantification and mapping of intraventricular mechanical dyssynchrony

Objectives The aim of the study is to compare two advanced methods of evaluation of left ventricular mechanical dyssynchrony (LVMD), the speckle tracking echocardiography (STE) and the three-dimensional echocardiography (3DE). Methods One hundred thirty-six subjects, with or without LV dysfunction and with or without bundle branch block (BBB), were included in this study, designed to investigate agreement between magnitude and spatial pattern of LVMD as assessed by 3DE and STE. The frequency and severity of LVMD and localization of most asynchronous segments were compared. Results Both 3DE and STE revealed progressive rise in frequency and magnitude of LVMD with increasing disease severity. Dyssynchrony was dependent on left ventricle ejection fraction rather than the QRS duration. The frequency and magnitude of dyssynchrony were maximum in patients having LV dysfunction with left BBB. Compared with STE, 3DE diagnosed LVMD more frequently in patients having LV dysfunction with narrow QRS (17.6% vs 60.3%, respectively; P < 0.001). When the two methods were compared for localization of most asynchronous segments, the results matched only in about 50% cases. Conclusions Both 3DE and STE provided consistent results with progressive rise in magnitude of LVMD, correlating with disease severity. 3DE diagnosed more patients as having LVMD in those having LV dysfunction with narrow QRS. The most delayed segment assessed by two methods matched only in about half the cases. Correlation with clinical CRT responsiveness is needed to conclude which method is more accurate in dyssynchrony mapping for targeted lead placement.

Real-time three-dimensional echocardiographic left heart parameters in healthy indian adults

Objective Cardiac chamber dimensions are race and anthropometry dependent. We determined the age and gender specific 3-Dimensional echocardiographic (3DE) reference values for dimensions and function of left ventricle (LV) and left atrium (LA) in normal Indian adults. Methods This single center prospective study enrolled 133 adult Indians free of heart disease and/or hypertensions, subjecting them to 3DE measurements of left atrial (LA) & left ventricular (LV) volumes, function and left ventricular mass (LVM). The higher limits of normal cut-offs were determined for these parameters and their dependency on age, gender and anthropometry were analyzed. Results The body surface area (BSA) corrected higher limit cut-offs were: 59.37 ml/m2 for LV end diastolic volume (59.19 ml/m2 and 59.61 ml/m2 for men and women, respectively; P = NS); 23.48 ml/m2 for LV end systolic volume (23.27 ml/m2 and 23.11 ml/m2 for men and women, P = NS). Mean LVEF was 64.79% ± 7.26 (62.99% ± 6.51 and 67.05% ± 7.58 in men and women, P = NS). Men had higher LVM than women (119.79 g±23.95 vs. 103.26 g±23.76, P < 0.001), this difference disappeared after BSA indexing. The higher limit cut-offs for normal LA volumes were 20.49 ml for minimum volume (21.18 ml and 19.46 ml for men and women, P = NS) and 39.76 ml for maximum volume (39.60 ml and 40.03 ml in men and women, P = NS). The parameters were smaller compared to western populations but the differences attenuated after BSA indexing. Conclusions The study reports normal 3DE parameters of size and function of left heart chambers in Indians.

Three-dimensional echocardiographic evaluation of mechanical dyssynchrony in systolic heart failure with narrow QRS complex

Objectives To investigate the role of three-dimensional echocardiography (3DE) in evaluation of left ventricular mechanical dyssynchrony (LVMD) in heart failure (HF) patients with narrow QRS. Methods 143 subjects (70 with HF and narrow QRS, 23 with HF and LBBB and 50 controls) were subjected to 3DE, evaluating global and regional dyssynchrony using systolic dyssynchrony index, maximum segmental dyssynchrony and opposite segment dyssynchrony. Spatial distribution of LVMD was studied in each patient using 3DE derived regional time volume curves. Extent of LVMD in HF patients with narrow QRS was compared to those with left bundle branch block (LBBB). Results Frequency of LVMD was similar in HF patients with narrow QRS or LBBB (55.7% vs. 47.8%, p = NS). There was no difference in the severity of LVMD between these two groups (10.7 ± 6.7% vs. 12.1 ± 7.4%, p = NS). Both HF groups had significantly more dyssynchrony than controls. A scattered pattern of distribution of asynchronous segments was seen in narrow QRS patients; 33.96% of them had their earliest contracting segment, instead of delayed segment, located in areas conventionally targeted for LV pacing i.e. anterolateral, inferolateral or inferior segments. Conclusions 3DE confirmed significant dyssynchrony in > 50% HF patients with narrow QRS as demonstrated by other imaging methods. 3D distribution patterns of asynchronous segments indicate possibility of left ventricular mechanics related reasons responsible for lack of CRT responsiveness, an observation that generates hypothesis on possible reasons of CRT non-responsiveness.