Beta-Blockers after Myocardial Infarction and Preserved Ejection Fraction

Area of Science:

• Cardiology
• Clinical Trials
• Pharmacology

Background:

• Previous studies showing beta-blocker benefits post-myocardial infarction (MI) often involved patients with larger MIs and predated modern treatments.
• Current evidence may not directly apply to contemporary MI patients receiving advanced therapies like percutaneous coronary intervention and high-intensity statins.

Purpose of the Study:

• To evaluate the efficacy of long-term beta-blocker treatment in patients with acute myocardial infarction and preserved left ventricular ejection fraction (LVEF).
• To assess the impact of beta-blockers on the composite endpoint of all-cause death or new myocardial infarction in this specific patient group.

Main Methods:

• A parallel-group, open-label trial randomized 5020 patients with acute MI and LVEF ≥50% to receive long-term beta-blockers (metoprolol or bisoprolol) or no beta-blocker.
• The primary endpoint was a composite of death from any cause or new myocardial infarction, with a median follow-up of 3.5 years.

Main Results:

• No significant difference in the primary endpoint was observed between the beta-blocker group (7.9%) and the no-beta-blocker group (8.3%), with a hazard ratio of 0.96 (95% CI, 0.79 to 1.16).
• Secondary endpoints, including all-cause death, cardiovascular death, myocardial infarction, and hospitalizations for atrial fibrillation or heart failure, also showed no significant benefit from beta-blocker treatment.
• Safety endpoints, such as bradycardia, heart block, hypotension, syncope, pacemaker implantation, and hospitalizations for respiratory conditions or stroke, were similar between the groups.

Conclusions:

• In patients with acute myocardial infarction who underwent early coronary angiography and had preserved LVEF (≥50%), long-term beta-blocker treatment did not reduce the risk of death or new myocardial infarction compared to no beta-blocker use.
• These findings suggest that the role of beta-blockers in post-MI management may need re-evaluation in the context of modern therapeutic strategies and specific patient characteristics like preserved LVEF.