Comparison of Echocardiographic Dyssynchrony Assessment by Tissue Velocity and Strain Imaging in Subjects With or Without Systolic Dysfunction and With or Without Left Bundle-Branch Block

Abstract

Background-Several echocardiographic dyssynchrony indexes have been proposed to identify responders to cardiac resynchronization therapy using tissue velocity and strain. The present study aimed to compare tissue velocity-derived and strain-derived dyssynchrony indexes in patients with or without systolic dysfunction and left bundle-branch block. Methods and Results-Tissue Doppler imaging was performed in 120 subjects divided into 4 groups: group 1 (nϭ40), normal subjects; group 2 (nϭ20), normal left ventricular ejection fraction and left bundle-branch block; group 3 (nϭ20), left ventricular ejection fraction Ͻ35% and normal conduction; and group 4 (nϭ40), left ventricular ejection fraction Ͻ35% and left bundle-branch block. Dyssynchrony indexes based on time to peak tissue velocity (septal-lateral delay, anteroseptal-posterior delay, and SD in time to peak systolic velocity in the 12 left ventricular segments) and strain (SD of time to peak strain in 12 segments) were measured. The SD in time to peak systolic velocity in the 12 left ventricular segments was greater in group 4 (54 ms; 25th and 75th percentiles, 46 to 64 ms) than group 1 (44 ms; 25th and 75th percentiles, 28 to 53 ms; Pϭ0.006), but there was a considerable overlap of all tissue velocity-derived indexes among 4 groups, with 40% to 68% of group 1 having values proposed for predicting the responders of cardiac resynchronization therapy. The SD of time to peak strain in 12 segments distinguished these groups with much less overlap (PϽ0.01 for all pairwise comparisons). Conclusions-A substantial proportion of normal subjects have tissue velocity-derived dyssynchrony indexes higher than the cutoff value proposed for predicting beneficial effect of cardiac resynchronization therapy. Strain-derived timing index appears to be more specific for dyssynchrony in patients with systolic dysfunction and left bundle-branch block.Identifying an optimal tissue velocity-or strain-derived dyssynchrony index requires a large prospective clinical trial.

The Speckle Tracking Imaging for the Assessment of Cardiac Resynchronization Therapy (START) Study

“…17 However, these attempts were challenged in prospective multicenter studies because of poor reproducibility, low positive predictive values, and poor accuracy even in healthy control subjects. 4-7, 18 Several studies suggested that STE overcame some limitations of tissue velocity imaging and provided a better measurement of mechanical dyssynchrony. The dyssynchrony parameters by STE were proposed as additional indices to predict CRT response in single-center studies or those with small sample sizes.…”

Left ventricular systolic synchrony and R-R interval in patients with coronary artery disease

“…According to American Heart Association Scientific Statement, the heart should be divided into 17 segments for assessment of the myocardium and the left ventricular cavity (10). The time to peak systolic longitudinal strain in (Tssl) of 17 LV segments has been paid much attention as LV systolic synchrony parameter recently (17)(18)(19). As the resting heart rate predicts longevity and cardiovascular diseases, and current evidence suggests that it is also an important marker of outcome in cardiovascular disease, including coronary artery disease (20).…”

Hype and Hope in the Use of Echocardiography for Selection for Cardiac Resynchronization Therapy

“…11 Strain measures deformation and therefore contraction and may overcome some of the problems cause by the inability of velocity to distinguish contraction from rocking movements and tethering. Miyazaki et al 11 compared measures of dyssynchrony with tissue velocity imaging (TVI) and strain in 120 subjects (40 normal, 20 LBBB with normal LV, 20 LV dysfunction and no LBBB, and 40 LV dysfunction and LBBB).…”