The purpose of the present study was to evaluate, in patients surviving the first postinfarction week, the short- and long-term prognostic implications of arrhythmias, and their relation to easily obtained anamnestic and clinical parameters presented during hospitaHsation. The study consisted of 897 placebo-treated patients of the Danish Verapamil Infarction Trial II (DAVIT II). In patients with and without supraventricular tachycardia mortality within 2 months was 9.2 and 3.7% (p = 0.004), respectively. By multivariate analysis supraventricular tachycardia independently predicted mortality within 2 months. Mortality within 5 years was predicted by the presence of supraventricular tachycardia, atrial fibrillation, advanced atrioventricular block, sinoatrial block, and of the combined arrhythmic parameter, i.e. ventricular and/ or atrial fibrillation and/or advanced atrioventricular block. When easily obtained and assessed anamnestic and clinical parameters were included in a multivariate analysis, the presence of supraventricular tachycardia alone gave independent prognostic information on long-term mortality.