Abstract Body (Do not enter title and authors here):
Background: Beta-blockers are a mainstay of therapy following myocardial infarction (MI), particularly in patients with reduced ejection fraction (EF). However, their benefit in patients with preserved or mildly reduced EF (EF >40%) who undergo percutaneous coronary intervention (PCI) remains uncertain. Despite current guideline support, evidence in this population is limited. This study aims to evaluate the clinical impact of beta-blockers using large-scale real-world data.

Methods: A retrospective cohort study was conducted using the TriNetX Collaborative Network from January 1, 2009, to January 1, 2025, with a 5-year follow-up. Patients with acute MI who underwent PCI and had an EF >40% were divided into two cohorts: those treated with beta-blockers and those not. The primary outcome was all-cause mortality. Secondary outcomes included all-cause hospitalization, recurrent MI hospitalization, heart failure hospitalization, new-onset atrial fibrillation, second-degree or complete atrioventricular (AV) block, and permanent pacemaker implantation.

Results: After PSM, 6,172 patients remained in each cohort. The mean age was similar between the beta-blocker group (69.1 ± 12.4 years) and the non–beta-blocker group (69.1 ± 12.2 years; p = 0.869). There was no significant difference in all-cause mortality (HR = 0.958; 95% CI: 0.787–1.168; p = 0.673). However, beta-blocker use was associated with lower risks of all-cause hospitalization (HR = 0.945; 95% CI: 0.906–0.986; p = 0.003), MI hospitalization (HR = 0.916; 95% CI: 0.876–0.958; p < 0.0001), and heart failure hospitalization (HR = 0.918; 95% CI: 0.864–0.976; p = 0.006). There were no significant differences in new-onset atrial fibrillation (HR = 1.013; 95% CI: 0.922–1.113; p = 0.790), AV block (HR = 0.878; 95% CI: 0.747–1.031; p = 0.113), or pacemaker implantation (HR = 0.736; 95% CI: 0.536–1.012; p = 0.059).

Conclusion: In post-MI patients with EF >40%, beta-blocker use was not associated with reduced mortality but was linked to lower rates of all-cause, MI-related, and heart failure–related hospitalizations.