To analyse the incidences of arrhythmiases, myocardial ischemia and the minimal heart rate detected by 24-hour dynamic electrocardiogram, three hundred and ninety-four elderly cases of 24-hour dynamic electrocardiogram were studied. The results were shown as follows: 1. the incidence rates of isolated superventricular ectopic beat 97.2%, and paired were 96.2%; nonparaxysmal superventricular tachycardia (SVT) was 55.6%, and paraxysmal SVT was 18.8% respectively. The incidence rates of isolated ventricular ectopic beat and paired were 85.3%, 16.2%, while nonparaxysmal ventricular tachycardia (VT) was 5.6%, paraxysmal VT was 1.8% respectively; 2. 6 cases of minimal heart rate less than 30 beats per minute without subjective symptoms was found while minimal beart rate did not decline with increase of age; 3. 81 (93.1%) of 87 cases (22.1%) who showed myocardial ischemia were completely asymptomatic. It is assumed that the occurances of superventricular and ventricular ectopic beats were of no clinic significance. However, it is important to pay more attention to those whose minimal heart rate is less than 30 beats per minute or who has had episodes of myocardial ischemia.