Left intraventricular myocardial deformation dyssynchrony identifies responders to cardiac resynchronization therapy in patients with heart failure.

AIMS We tested the hypothesis that dyssynchrony of left ventricular (LV) myocardial deformation evaluated by ultrasound can predict success of cardiac resynchronization therapy (CRT) in patients with heart failure (HF). METHODS AND RESULTS Thirty-seven patients with dilated cardiomyopathy, New York Heart Association class III-IV, LV ejection fraction (EF) < or =35%, QRS > 120 ms were studied before, at pre-discharge, and after 3 and 6 months of CRT. The M-mode peak septal-to-posterior wall motion and thickening delay (SPWMD and SPWTD, ms) and the standard deviation of the averaged time-to-peak strain (TPS-SD, ms) of 12 middle and basal LV segments obtained from the three standard apical views were calculated. Responders were defined at month 6 by > or =20% EF increase and/or > or =15% end-systolic volume (ESV) decrease with respect to baseline. Baseline SPWTD (not SPWMD) and TPS-SD differentiated responders from non-responders with good accuracy and reproducibility. A value > or =194 ms for SPWTD and > or =60 ms for TPS-SD was significantly associated with responder identification. Baseline dyssynchrony parameters correlated significantly with EF (r = 0.53 for SPWTD and r = 0.86 for TPS-SD) and ESV variations (r = -0.42 for SPWTD and r = -0.73 for TPS-SD). CONCLUSION Patients with chronic HF should undergo ultrasound evaluation to quantify dyssynchrony of LV myocardial deformation, which would help identifying CRT responders.