Cardiac Resynchronization Therapy in Patients with Mild Heart Failure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

This review aims at updating the results of cardiac resynchronization therapy (CRT) in mild heart failure patients, and investigating whether CRT can prevent or reverse heart failure progression in an earlier stage. Randomized controlled trials of CRT in patients with New York Heart Association (NYHA) Class I or II heart failure were identified. The effects of CRT on worsening heart failure hospitalization, all-cause mortality, and overall adverse events were meta-analyzed, and the effects of CRT on left ventricular (LV) were systematically reviewed and meta-analyzed. Eight studies were identified with a total of 4,302 patients. CRT was associated with a substantial improvement in LV end-systolic volume (WMD -39, 95%CI -41.56 to -36.45). CRT also had a marked effect in reducing new hospitalizations for worsening heart failure by 31% (RR 0.69, 95%CI 0.60 to 0.79). In addition, CRT significantly decreased all-cause mortality by 21% (RR 0.79, 95%CI 0.67 to 0.93). However, complications in patients with CRT increased by 74% (RR 1.74, 95%CI 1.44 to 2.11). This meta-analysis suggests that CRT could improve the prognosis in patients with mild heart failure and ventricular dyssynchrony, but these improvements are accompanied by more adverse events. Since most patients in the included trials had received ICD therapy, our analysis suggests that CRT could offer an additional benefit.