Mechanical dyssynchrony evaluated by tissue Doppler cross-correlation analysis is associated with long-term survival in patients after cardiac resynchronization therapy

Pre-implant assessment of longitudinal mechanical dyssynchrony using cross-correlation analysis (XCA) was tested for association with long-term survival and compared with other tissue Doppler imaging (TDI)-derived indices. In 131 patients referred for cardiac resynchronization therapy (CRT) from two international centres, mechanical dyssynchrony was assessed from TDI velocity curves using time-to-peak opposing wall delay (OWD) epsilon 80 ms, Yu index epsilon 32 ms, and the maximal activation delay (AD-max) 35 ms. AD-max was calculated by XCA of the TDI-derived myocardial acceleration curves. Outcome was a composite of all-cause mortality, cardiac transplantation, or implantation of a ventricular assist device (left ventricular assist device) and modelled using the Cox proportional hazards regression. Follow-up was truncated at 1460 days. Dyssynchrony by AD-max was independently associated with improved survival when adjusted for QRS 150 ms and aetiology {hazard ratio (HR) 0.35 [95 confidence interval (CI) 0.160.77], P 0.01}. Maximal activation delay performed significantly better than Yu index, OWD, and the presence of left bundle branch block (P 0.05, all, for difference between parameters). In subgroup analysis, patients without dyssynchrony and QRS between 120 and 150 ms showed a particularly poor survival [HR 4.3 (95 CI 1.4612.59), P 0.01, compared with the group with dyssynchrony and QRS between 120 and 150 ms]. Mechanical dyssynchrony assessed by AD-max was associated with long-term survival after CRT and was significantly better associated compared with other TDI-derived indices. Patients without dyssynchrony and QRS between 120 and 150 ms had a particularly poor prognosis. These results indicate a valuable role for XCA in selection of CRT candidates.