Background beta-Blockers have a class 1a recommendation in the treatment of patients with ST-elevation myocardial infarctions (STEMIs), as they are associated with a reduced mortality, recurrent myocardial infarction, life-threatening arrhythmias, and with prevention of unfavorable left ventricular remodeling. Whether early administration before primary percutaneous coronary intervention (PCI) of intravenous beta-blockers reduces the infarct size in the current era is unknown.
Hypothesis We postulate that the early administration of beta-blockers will reduce the myocardial infarcted area as assessed by magnetic resonance imaging (MRI) at 30 days.
Design In a multinational, multicenter, double-blind, placebo-controlled, randomized trial, patients with symptoms and signs of STEMI and transferred to a hospital for primary PCI will be randomized in a 1:1 fashion to intravenous metoprolol (5 mg twice daily) administration or placebo. Before admission, study treatment will be started as soon as possible after the diagnosis of STEMI. After admission, primary PCI will be performed as per standard of care. After primary PCI, medical treatment will occur as per current guidelines in all patients, including the use of oral beta-blockers. The primary end point is the myocardial infarct size as assessed by MRI at 30 days. Based on a superiority design and assuming an 18% relative infarct size reduction (from 28% to 23.5%), 408 patients are required to be enrolled, accounting for 20% drop-out (alpha =.05 and power = 80%).
Summary The EARLY-BAMI trial is a multinational, multicenter, double-blind, placebo-controlled, randomized clinical trial that will investigate the impact of intravenous metoprolol administration before primary PCI for STEMI on myocardial infarct size as measured with MRI at 30 days.