Improvement in Right Ventricular Systolic Function after Cardiac Resynchronization Therapy Correlates with Left Ventricular Reverse Remodeling

Abstract

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