Effect of QRS Narrowing After Cardiac Resynchronization Therapy on Functional Mitral Regurgitation in Patients With Systolic Heart Failure

摘要

The determinants of improvement in functional mitral regurgitation (FMR) after cardiac resynchronization therapy (CRT) remain unclear. We evaluated the predictors of FMR improvement and hypothesized that CRT-induced change in QRS duration (Delta QRS) might have an impact on FMR response after CRT. One hundred ten CRT recipients were enrolled. CRT response (>= 15 reduction in left ventricular end-systolic volume) and FMR response (absolute reduction in FMR volume) were assessed with echocardiography before and 6 months after CRT. The study end points included all-cause death or hospitalization assessed in 12 +/- 3 months (range 1 to 18). A total of 71 patients (65%) responded to CRT at 6 months. FMR response was observed in 49 (69%) of the CRT responders and 8 (20%) of the CRT nonresponders (p <0.001). Although the baseline QRS durations were similar, the paced QRS durations were shorter (p = 0.012) and the Delta QRS values were greater (p = 0.003) in FMR responders compared with FMR nonresponders. There was a linear correlation between Delta QRS and change in regurgitant volume (r = 0.49, p <0.001). At multivariate analysis, baseline tenting area (p = 0.012) and Delta QRS (p = 0.028) independently predicted FMR response. A Delta QRS >= 20 ms was related to CRT response, FMR improvement, and lower rates of death or hospitalization during follow-up (p values <0.05). In conclusion, QRS narrowing after CRT independently predicts FMR response. A Delta QRS >= 20 ms after CRT is associated with a favorable outcome in all clinical end points. (C) 2016 Elsevier Inc. All rights reserved.