Cardiac resynchronization therapy in continuous flow left ventricular assist device recipients: A systematic review and meta-analysis from ELECTRAM investigators

Introduction: Whether cardiac resynchronization therapy (CRT) continues to augment left ventricular remodeling in patients with the continuous-flow left ventricular assist device (cf-LVAD) remains unclear. Methods: We performed a systematic review and meta-analysis of all clinical studies examining the role of continued CRT in end-stage heart failure patients with cf-LVAD reporting all-cause mortality, ventricular arrhythmias, and ICD shocks. Mantel-Haenszel risk ratio (RR) random-effects model was used to summarize data. Results: Eight studies (7 retrospective and 1 randomized) with a total of 1,208 unique patients met inclusion criteria. There was no difference in all-cause mortality (RR 1.08, 95% CI 0.86-1.35, p = 0.51, I2=0%), all-cause hospitalization (RR 1.01, 95% CI 0.76-1.34, p = 0.95, I2=11%), ventricular arrhythmias (RR 1.08, 95% CI 0.83-1.39, p = 0.58, I2 =50%) and ICD shocks (RR 0.87, 95% CI 0.57-1.33, p = 0.52, I2 =65%) comparing CRT versus non-CRT. Subgroup analysis demonstrated significant reduction in ventricular arrhythmias (RR 0.76, 95% CI 0.64-0.90, p = 0.001) and ICD shocks (RR 0.65, 95% CI 0.44-0.97, p = 0.04) in "CRT on" group versus "CRT off" group. Conclusion: CRT was not associated with a reduction in all-cause mortality or increased risk of ventricular arrhythmias and ICD shocks compared to non-CRT in cf-LVAD patients. It remains to be determined which subgroup of cf-LVAD patients benefit from CRT.The findings of our study are intriguing, and therefore,larger studies in a randomized prospective manner should be undertaken to address this specifically.