Science, Medicine, and the Anesthesiologist

The efficacy of β-blocker use after myocardial infarction for secondary prevention is controversial. This parallel-group, open-label trial (September 2017 to May 2023; 45 centers in Sweden, Estonia, and New Zealand) of patients with acute myocardial infarction (obstructive disease on coronary angiography; left ventricular ejection fraction of at least 50%) randomized 5,020 patients to either long-term treatment with a β blocker (100 mg metoprolol daily or at least 5 mg bisoprolol daily) (N = 2,508) or no β-blocker treatment (N = 2,512). The primary endpoint was a composite of death from any cause or new myocardial infarction. Cohort characteristics included median age 65 yr, 22.5% female, and 35.2% ST-segment elevation myocardial infarction. The median follow-up was 3.5 yr (interquartile range, 2.2 to 4.7 yr). There was no difference in the primary outcome between groups (7.9% β blocker vs. 8.3% without; hazard ratio, 0.96; 95% CI, 0.79 to 1.16; P = 0.64). As well, no differences were noted in secondary endpoints (death from any cause, 3.9% vs. 4.1%; death from cardiovascular causes, 1.5% vs. 1.3%; myocardial infarction, 4.5% vs. 4.7%; hospitalization for atrial fibrillation, 1.1% vs. 1.4%; and hospitalization for heart failure, 0.8% vs. 0.9%). No differences in a variety of safety endpoints were noted.

Take home message: This large, parallel-group, randomized trial of primarily European patients with predominantly non–ST-segment elevation myocardial infarction and left ventricular ejection fraction greater than or equal to 50% demonstrated no difference in death or new myocardial infarction with or without the use of β blockers for secondary prevention over a 3.5-yr median follow-up period.