The clinical characteristics of patients with dilated cardiomyopathy and bradyarrhythmias were studied. Among 50 patients with dilated cardiomyopathy, 6 had bradyarrhythmias. Among these patients were one with sinus bradycardia, one with atrial fibrillation and slow ventricular responses and sick sinus syndrome (SSS), one with SSS with advanced AV block, and 3 with advanced AV block. The average age at the onset of their cardiac symptoms (60.3 +/- 12.1 years (mean +/- SD)) was significantly (p less than 0.01) higher than that of 43 patients without bradyarrhythmias (40.0 +/- 17.6). The left ventricular diastolic dimension and ejection fraction were similar among patients with and without bradyarrhythmias. In 31 follow-up patients without bradyarrhythmias, 8 (25.8%) died of cardiac causes; whereas, in 5 patients with bradyarrhythmias, 4 had been implanted with pacemakers and 3 (60.0%) died of cardiac causes. Furthermore, the age at the onset of cardiac symptoms in patients with any kind of conduction disturbance, except tachyarrhythmia, was 50.4 +/- 16.5 years (n = 25), which was significantly higher (p less than 0.02) than that of patients without conduction disturbances (37.7 +/- 19.3 years, n = 23). We concluded that bradyarrhythmias are not rare complications in patients with dilated cardiomyopathy, and the mortality rate tends to be higher in patients with bradyarrhythmias than in those without them. Furthermore, the risks of conduction disturbances and bradyarrhythmias were higher in the elderly patients.