Sudden death and acute myocardial infarction: clues to differences in pathophysiology.

Although both sudden death and acute myocardial infarction are almost always associated with long-standing obstructive coronary artery disease, both may originate in the myocardium. Spasm has been suggested as a factor contributing to sudden death. Not all persons dying of acute myocardial infarction have narrowed coronary arteries, nor do all persons with obstructed arteries die of heart disease. The first phase of acute myocardial infarction may well involve myocardial necrosis, followed by stasis and collapse of collateral circulation and occasionally by coronary occlusion.