BACKGROUND The impact of intravenous (IV) beta-blockers before primary percutaneous coronary intervention (PPCI) on infarct size and clinical outcomes is not well established.
OBJECTIVES This study sought to conduct the first double-blind, placebo-controlled international multicenter study testing the effect of early IV beta-blockers before PPCI in a general ST-segment elevation myocardial infarction (STEMI) population.
METHODS STEMI patients presenting
RESULTS A total of 683 patients (mean age 62 +/- 12 years; 75% male) were randomized to metoprolol (n = 336) or placebo (n = 346). CMR was performed in 342 patients (54.8%). Infarct size (percent of left ventricle [LV]) by CMR did not differ between the metoprolol (15.3 +/- 11.0%) and placebo groups (14.9 +/- 11.5%; p = 0.616). Peak and area under the creatine kinase curve did not differ between both groups. LV ejection fraction by CMR was 51.0 +/- 10.9% in the metoprolol group and 51.6 +/- 10.8% in the placebo group (p = 0.68). The incidence of malignant arrhythmias was 3.6% in the metoprolol group versus 6.9% in placebo (p = 0.050). The incidence of adverse events was not different between groups.
CONCLUSIONS In a nonrestricted STEMI population, early intravenous metoprolol before PPCI was not associated with a reduction in infarct size. Metoprolol reduced the incidence of malignant arrhythmias in the acute phase and was not associated with an increase in adverse events. (C) 2016 by the American College of Cardiology Foundation.