Efficacy of Beta-Blockers and Angiotensin-Converting Enzyme Inhibitors in Non-Ischemic Dilated Cardiomyopathy: A Systematic Review and Meta-Analysis

Non-ischemic dilated cardiomyopathy (NIDCM) is a form of heart failure with a poor prognosis and unclear optimal management. The aim of the study was to systematically review the literature and assess the efficacy and safety of beta-blockers and angiotensin-converting enzyme (ACE) inhibitors in the management of chronic heart failure secondary to NIDCM and explore their putative mechanisms of action. Studies from 1990 to 2023 were reviewed using PubMed and EMBASE, focusing on their effects on left ventricular ejection fraction (LVEF) in NIDCM patients, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Beta-blockers showed a significant beneficial effect on LVEF improvement in NIDCM, with an overall effect size of Cohen's = 1.30, 95% confidence interval (CI) (0.76, 1.84), high heterogeneity (Tau = 0.90; Chi = 162.05, df = 13, P < 0.00001; I = 92%), and a significant overall effect (Z = 4.72, P < 0.00001). ACE inhibitors also showed a beneficial role, but with less heterogeneity (Tau = 0.02; Chi = 1.09, df = 1, P = 0.30; I = 8%) and a nonsignificant overall effect (Z = 1.36, P = 0.17), 95% CI (-0.24, 1.31). The study highlights the efficacy of carvedilol in improving LVEF in NIDCM patients over ACE inhibitors, recommends beta-blockers as first-line therapy, and advocates further research on ACE inhibitors.