Antiarrhythmic effect of carvedilol after acute myocardial infarction - Results of the Carvedilol Post-Infarct Survival Control in Left Ventricular Dysfunction (CAPRICORN) trial

OBJECTIVES Whether beta-blockers reduce atrial arrhythmias and, when added to an angiotensin-converting enzyme (ACE) inhibitor, ventricular arrhythmia is unknown. BACKGROUND Ventricular and atrial arrhythmias are common after acute myocardial infarction (AMI) and are associated with a poor prognosis. Anglotensin-converting enzyme inhibitors reduce the incidence of both types of arrhythmia. METHODS The antiarrhythmic effect of carvedilol was examined in a placebo-controlled multicenter trial, the Carvedilol Post-Infarct Survival Control in Left Ventricular Dysfunction (CAPRICORN) study, which enrolled 1,959 patients with reduced left ventricular systolic function after AMI, 98% of whom were treated with an ACE inhibitor. RESULTS The incidence of atrial fibrillation/flutter was 53 to 984 (5.4%) in the placebo group and 22 to 975 (2.3%) in the carvedilol group, giving a carvedilol/placebo hazard ratio (HR) of 0.41 (95% confidence interval [CI] 0.25 to 0.68; p = 0.0003). The corresponding rates of ventricular tachycardia/flutter/fibrillation were 38 to 984 (3.9%) and 9 to 975 (0.9%) (HR 0.24, 95% CI 0.11 to 0.49; p < 0.0001). CONCLUSIONS Carvedilol has a powerful antiarrhythmic effect after AMI, even in patients already treated with an ACE inhibitor. Carvedilol suppresses atrial as well as ventricular arrhythmias in these patients. (C) 2005 by the American College of Cardiology Foundation.