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-l), 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-l (area under the curve [AUC] 0.69), LV-SD6-c (AUC 0.66), LV-SD6-r (AUC 0.79), LV-t (AUC 0.81), and RV-SD6+LV-SD6-r (AUC 0.83). By combining LV and RV intraventricular dyssynchrony (LV-SD12-l + LV-SD6-r + RV-SD6), the AUC was significantly improved to 0.89 (P < .005 compared with RV-SD6+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.