Patients after myocardial infarction have a high incidence of both frequent and complex ventricular arrhythmias. Arrhythmias detected by 24-hour electrocardiographic recordings at hospital discharge are predictive of next cardiac mortality. Both left ventricular dysfunction and ventricular arrhythmias have been associated with poor prognosis following acute myocardial infarction. But dysfunction of the left ventricle and ventricular arrhythmias are independently related to mortality. This finding provides a rationale for treating patients with frequent and/or complex ventricular arrhythmias detected at hospital discharge after acute myocardial infarction. Beta-blockers should be considered as antiarrhythmic drugs of choice in the treatment of postinfarction patients with ventricular arrhythmias in order to reduce both ventricular arrhythmias and cardiac mortality.