Improvement in right ventricular systolic function after cardiac resynchronization therapy correlates with left ventricular reverse remodeling.

Background: Cardiac resynchronization therapy (CRT) improves left ventricular (LV) systolic function in heart failure (HF). However, the effects of CRT on right ventricular (RV) systolic function are not fully understood.

Objective: We aimed to determine echocardiographic correlates of improvement in RV systolic function after CRT.

Methods: Fifty-four patients (61.9 ± 10.5 years; 43 men; LV ejection fraction 24.6 ± 4.0%; QRS duration > 120 ms) with HF were enrolled. Standard echocardiography, strain rate (SR), and tissue Doppler imaging were performed in all patients before and 6 months after CRT. Pulsed-wave TDI-derived systolic indices of RV included systolic (RV(S) ) and isovolumic velocity (RV(IVV)) and isovolumic acceleration (RV(IVA)). Response to CRT was defined as decline in LV end-systolic volume (LVESV) ≥ 10%.

Results: When indices of RV systolic function were assessed between responders and nonresponders, in responders (38 patients, 70.4%) RV end-diastolic diameters (RVD1-3), mid-RV strain, and mid-RV SR improved significantly (P < 0.01, for all). RV(S) (10.77 ± 4.29 vs 12.62 ± 4.10 cm/sec, P = 0.005), RV(IVV) (14.71 ± 5.88 vs 18.52 ± 6.62 cm/sec, P < 0.001), and RV(IVA) (1.69 ± 0.70 vs 2.39 ± 0.77 m/sec(2) , P < 0.001) significantly increased among responders. There was no significant change in these parameters among nonresponders. Pearson's analyses revealed moderate positive correlations between reduction of LVESV and ΔRV(IVV) (r = 0.467, P = 0.001) and ΔRV(IVA) (r = 0.473, P = 0.001), respectively.

Conclusions: RV diameters and systolic indices after CRT improved only in the responder group. Improvement in RV systolic performance after CRT is correlated with the reduction of LVESV.