Temporal trends in the treatment with beta-blocker and the effect on outcome of patients with acute myocardial infarction.

Background: Early beta-blocker treatment has long been recommended for patients with acute myocardial infarction (AMI), particularly when left ventricular ejection fraction (LVEF) is reduced; however, whether beta-blocker therapy improves outcomes in patients with AMI receiving contemporary treatment remains uncertain. This study aimed to investigate temporal trends in the effect of beta-blocker therapy on outcomes of patients with AMI in a large, nationwide cohort.

Methods: Patients with AMI enrolled in the Acute Coronary Syndromes Israeli Survey from 2000 to 2021 were included. They were categorized into three periods: early (2000-2004), mid (2006-2016), and late (2018-2021). Each period group was further divided into two subgroups based on LVEF (>40 and ≤40%) and then stratified by beta-blocker treatment status.

Results: The cohort consisted of 11 569 patients. Among patients with LVEF less than 40%, beta-blocker treatment was associated with improved 1-year survival rates in the early (9.1 vs. 20.4%; P < 0.001) and mid (10 vs. 20.6%; P < 0.001) periods only. Among patients with LVEF greater than or equal to 40%, beta-blocker treatment was linked to enhanced 1-year survival in patients enrolled in the early period (3.4 vs. 7.6%; P < 0.001), but not in the mid and late periods.

Conclusion: The association between beta-blocker treatment and improved survival in patients with AMI has diminished over recent decades, regardless of LVEF. These findings are likely attributed to the advancements in contemporary medical and revascularization therapy. As such, our results may challenge current recommendations regarding beta-blocker therapy in AMI.