Cardiac disease is common in patients with cerebrovascular disease (CVD) and cerebral lesions as such may influence cardiac activity and rhythm. To study the indication for continuous ECG surveillance of patients with CVD, 100 consecutive patients admitted to a medical stroke unit were investigated with 24-hour Holter recordings. The patients' mean age was 73 years and 70% of them had a history of heart disease. Twenty-three patients had chronic atrial fibrillation and 55% of the remainder showed ventricular ectopic activity. Serious ventricular arrhythmias were comparatively rare and mainly seen in association with signs of congestive heart failure and acute myocardial infarction. A prolonged Q-T interval was registered in two-thirds of the patients but there was no significant association between this finding and ventricular ectopic activity. Close observation for cardiac complications is important in patients with CVD and continuous ECG surveillance is indicated in selected high-risk patients.