Circadian variation in the onset of pain of acute myocardial infarction in Indian patients

Abstract

Two hundred patients admitted with acute myocardial infarction (AMI) to the coronary care unit of a tertiary-care-teaching hospital over a period of 1.5 years were studied prospectively, with regard to the time of onset of pain of infarction. The maximum number of infarctions (i.e. 71) (35.6%) occurred between 4.00 AM and 10.00 AM, significantly higher than other 6 hour periods of the day (P < 0.01). Various possible mechanisms leading to this early morning increase in the incidence of AMI and its therapeutic implications are discussed.