Background: The effects of diabetes mellitus and its treatment on the circadian variation of symptom onset in acute myocardial infarction were examined.
Methods: We obtained the time of symptom onset in 336 patients who had suffered acute myocardial infarction.
Results: As in earlier studies, the peak of symptom onset occurred in the late morning, between 6:01 a.m. and 12:00 noon. Although a similar circadian variation was observed in non-diabetic patients, the late-morning peak was less prominent in diabetic patients. In diabetic patients receiving treatment, however, the circadian pattern was well preserved, whereas in untreated diabetic patients there were no peaks in the distribution of symptom onset of acute myocardial infarction.
Conclusion: These findings suggest that autonomic disturbances in diabetes mellitus may blunt the late-morning peak in the frequency of onset of acute myocardial infarction.