Ageing and circadian variation in cardiovascular events

Circadian variation in cardiovascular events is well recognised in vascular events. This study aims to observe any significant difference in circadian variability in geriatric patients when compared to their younger counterparts.

This prospective study was conducted at medical emergency at the Government Medical College and Hospital, Chandigarh, India. All the patients attending medical emergency with symptoms suggestive of coronary artery disease were included. The time of occurrence of first symptom and subsequent symptoms was noted. Electrocardiography, cardiac enzymes and echocardiography were performed to establish the diagnosis of acute coronary syndrome. The 24-hour day was divided into 12 equal parts of two hours each. For the final analysis, the two-hour periods were grouped into six equal periods of four hours each and four quarters of six hours each.

We studied 559 patients, out of whom 459 were 65 years old or younger, and 100 patients were older than 65 years old. 459 patients had 498 episodes in all. 100 patients above the age of 65 years had 104 episodes. Both the groups had peaking of acute myocardial infarction in the early morning hours with patients older than 65 years of age having a slightly early peak. However, there was considerable variability for peaking of unstable angina and non-Q myocardial infarction. In patients older than 65 years, early morning peaking of events was noted whereas in 65 years or younger, the peaking of events was noted in the evening hours.

Circadian variability exists in occurrence of acute coronary events and is variable in geriatric patients when compared to their younger counterparts.