Circardian variation in the onset of cardiovascular events includig sudden cardiac death, myocardial infarction and ventricular arrhythmias has been discribed. The frequency of ventricular premature complexes has also been reported to demonstrate a pattern consisting of a daytime peak and nightime nadir. We tried to see if the same circardian pattern is found in dilated cardiomyopathy patients. We have also studed how various modifying factors such as left ventricular ejection fration and ACE inhibitor use may affect the circardian pattern.

24-hour ambulatory electrocaridiographic monitorings were performed in 50 dilated cardiomyopathy patients and 20 control subjects. Patients were prospectively divided in 2 groups based on LVEF and ACE inhibitor use.

In dilated cardiomyopathy patients, the expected morning increase in VPC frequency is absent and show a peak in evening. This pattern is not correlated with heart rate. Evening peak is more prominent in low LVEF group and ACE inhibitor non-user group.

In dilated cardiomyopathy patients, VPC frequency show a peak in the evening.