Probable triggers of onset of acute myocardial infarction.

Three cases of acute myocardial infarction are presented in which a probable triggering mechanism can be identified. The presence of triggering physical and mental stresses is consistent with recent documentation of a morning increase in frequency of acute myocardial infarction. This documentation suggests that the onset of acute myocardial infarction is not a random event. Recent advances in knowledge of the pathophysiology of acute myocardial infarction provide a background to the understanding of the probable triggering mechanism in these three cases. Further prospective study of patients with acute myocardial infarction in whom detailed information is collected sufficient to identify triggering activities may provide important insight into the pathophysiology of myocardial infarction and improved strategies for prevention.