Additive Value of Right Ventricular Dyssynchrony Indexes in Predicting the Success of Cardiac Resynchronization Therapy: A Speckle-Tracking Imaging Study

Background: The purpose of our study was to analyze the evolution of left and right ventricular (LV, RV) parameters before and after cardiac resynchronization therapy (CRT) using speckle-tracking imaging (STI). Methods and Results: Eighty-one patients with dilated cardiomyopathy (New York Heart Association functional class III or IV), left bundle branch block (QRS >= 120 ms), and LV ejection fraction >= 35% were studied with STI echocardiography before and after CRT. LV longitudinal (LV-SD12-1), radial (LV-SD6-r), and circumferential (LV-SD6-c) intraventricular dyssynchrony and LV twist (LV-t) were determined. RV dyssynchrony (RV-SD6) was defined as the standard deviation of the 6 time to peak systolic strain values. At 6 months' follow-up after CRT, the degree of dyssynchrony correlated significantly with LV ejection fraction improvement and end-systolic volume reduction. In receiver operating characteristic curve analysis, the following variables predictive of successful CRT were obtained: LV-SD12-1 (area under the curve [AUCJ 0.69), LV-SD6-c (AUC 0.66), LV-SD6-r (AUC 0.79), LV-t (AUC 0.81), and RV-SD6-ELV-SD6-r (AUC 0.83). By combining LV and RV intraventricular dyssynchrony (LV-SD 12-1 LV-SD6-r + RV-SD6), the AUC was significantly improved to 0.89 (P < .005 compared with RV-SD6-1-LV-SD6-r; P < .001 compared with LV-t). Conclusions: Our data show that assessment of RV dyssynchrony parameters has an incremental value in the evaluation of candidates for CRT and may supplement LV dyssynchrony information. (J Cardiac Fail 2011;17:392-402)