Beta-blocker therapy for acute myocardial infarction with preserved ejection fraction: A meta-analysis from randomized controlled trials

Background Immediate administration of beta-blockers is recommended for acute myocardial infarction (AMI). However, the benefit of beta-blockers according to left ventricular ejection fraction (LVEF), especially for preserved LVEF, remains uncertain. This study aimed to examine the efficacy and safety of beta-blockers for patients with mildly reduced or preserved LVEF after AMI. Methods We reviewed randomized controlled trials (RCTs) comparing standard therapy with versus without beta-blockers for patients with AMI with LVEF ≥40%. The primary outcome was a composite of all-cause death, myocardial infarction, and hospitalization for heart failure. The safety outcome was hospitalization for a composite of bradycardia, atrioventricular block, and pacemaker implantation. A pairwise meta-analysis was performed to evaluate hazard ratios (HRs) with 95% confidence intervals (CIs) using a random-effect model. Results A total of 19,826 participants from four RCTs (9892 received beta-blocker therapy and 9934 received non-beta-blocker therapy) were included. The primary outcome (HR, 0.93; 95% CI, 0.82–1.04) and the safety outcome (HR, 1.06; 95% CI, 0.83–1.34) were comparable between the two groups. Beta-blockers were also not associated with significant different risks of other outcomes, including each component of the primary outcome and stroke. Conclusions In patients with AMI with preserved LVEF, beta-blocker therapy was not significantly associated with lower cardiovascular outcomes or higher bradyarrhythmic events compared to non-beta-blocker therapy. Further trials are warranted to clarify the role and necessity of beta-blockers.