Multi-plane mechanical dyssynchrony in cardiac resynchronization therapy

Abstract

Background: The aims of this study were to assess the ability of several echo measures of dyssynchrony to predict CRT response and to characterize the global effect of CRT. Hypothesis: We hypothesized that after CRT there would be significant reductions in mechanical dyssynchrony in all 3 orthogonal planes of cardiac motion and that those patients with significant dyssynchrony prior to implant would have the best echocardiographic response. Methods: Standard echocardiograms were performed pre-CRT and post-CRT (138 ± 63d) in 70 heart failure patients. Longitudinal dyssynchrony was calculated as the standard deviation (SD) of time to peak systolic displacement and velocity of 12 segments from 3 apical views. Using midventricular short axis views and speckle-tracking methods, the SD of time to peak radial and circumferential strain in 6 segments were calculated. Cardiac resynchronization therapy echo responsewas defined as ≥ 15%decrease in left ventricular end-systolic volume. Results: Cardiac resynchronization therapy significantly improved systolic function in the longitudinal, radial, and circumferential planes. The CRT echo response rate was 57%. Echo responders (CRTR) had significantly (P< .05) more dyssynchrony at baseline as compared to nonresponders (CRTNR). Cardiac resynchronization therapy significantly (P