Circadian variations in cardiovascular disease: implications for treatment.

This review describes circadian patterns in cardiovascular disease processes and analyses the findings of recent studies. The awareness of an increased incidence of myocardial infarction and sudden cardiac death in the early morning hours, shortly after waking, has stimulated an interest in the relationship of these events and the occurrence of both silent and symptomatic myocardial ischaemia. A number of studies have been reported that examine both the physiological triggers and the underlying causes of these events. Beta-adrenergic blockers have been shown to abolish the early morning peak of myocardial infarction and blunt the morning peak in sudden cardiac death. Newer calcium antagonists, such as amlodipine, have been demonstrated to control angina throughout a 24-hour period. Aspirin is effective in preventing morning infarction. It is a reasonable aim for investigators to extend progress in the treatment of cardiovascular disease to include prevention.