The Role of Oral β-Blockers in Patients With Acute Myocardial Infarction with Preserved or Mildly Reduced Left Ventricular Systolic Function: A Systematic Review and Meta-Analysis

Abstract

Purpose: In patients with acute myocardial infarction (AMI) and preserved or mildly reduced left ventricular ejection fraction (LVEF), there is clinical uncertainty about the effectiveness of β-blockers in reducing mortality. We therefore investigated the effect of oral β-blockers on clinical benefit in patients with AMI with preserved or mildly reduced LVEF.

Methods: We conducted a comprehensive systematic search using PubMed, Embase, Cochrane Library, and ClinicalTrials.gov from January 1, 2000 to May 1, 2025, and finally included 16 observational studies and 2 randomized controlled trials (RCTs) to assess the β-blockers on patients with AMI with preserved or mildly reduced LVEF. The primary outcome was all-cause death, and the secondary outcomes were cardiac death, major adverse cardiovascular events, recurrent MI, hospitalization for heart failure, and stroke.

Findings: According to the search strategy, we finally included 18 studies, of which 16 were observational studies and 2 were RCTs. In the 5 studies without propensity score matching data, all-cause death was significantly lower in the β-blocker group than in the no β-blocker group (odds ratio [OR]: 0.65; 95% CI, 0.53-0.80). In the propensity score-matched 10 observational researches and 2 RCTs, there were no significant differences in all-cause death between the 2 groups. β-Blockers seemed to significantly reduce all-cause death in both non-ST-segment elevation myocardial infarction and ST-segment elevation myocardial infarction (OR = 0.44; 95% CI, 0.24-0.82; OR = 0.62; 95% CI, 0.40-0.98). β-Blockers seemed to be more effective in lowering all-cause death and cardiac death in patients with AMI and an LVEF of 40% to 50% (OR = 0.70; 95% CI, 0.50-0.97), and in the group with a follow-up time of ≥ 3 years, the use of β-blockers was significantly more effective in reducing cardiac death compared with the group with a follow-up time of <3 years (OR = 0.45; 95% CI, 0.23-0.88).

Implications: β-Blockers did not significantly reduce all-cause death and cardiac death in patients with AMI with preserved or mildly reduced LVEF. However, it seemed that patients with an LVEF of 40% to 50% might experience significant benefits in terms of long-term efficacy.

Keywords: Acute myocardial infarction; Mildly reduced left ventricular ejection fraction; Preserved left ventricular ejection fraction; Reperfusion; β-blocker.