Extensive myocytolysis as a marker of sudden cardiac death.
Colliquative myocytolysis, an intracellular vacuolization of myocardial cells, is considered an indicator of acute myocardial ischemia. Although often present in ischemic cardiac death, this lesion is often either overlooked, or not utilized as a criterion for diagnosing ischemia. This study reports light microscopic and ultrastructural studies of six autopsied patients who died suddenly and showed extensive myocytolysis as the only pathologic finding. In two of these patients, the clinical history and electrocardiogram findings documented an acute ischemic episode 1 to 3 hours antemortem. Six control patients with matched age and postmortem intervals did not show the intracellular vacuolization characteristic of myocytolysis. The postmortem intervals ranged from 2 to 12 hours. Ultrastructurally, myocytolysis was seen as a well-defined large intracellular vacuole without any lining membrane and associated with disrupted myofibrils, prominent Z band degeneration, and a few fat droplets. The mitochondria showed swelling and disruption, as well as electron dense amorphous inclusions. The swelling and disruption of mitochondria are well-known postmortem artefacts, and the mitochondrial amorphous inclusions, large intracellular vacuoles, prominent Z band degeneration, and fat droplets are not seen with autolysis. We conclude that myocytolysis, especially if extensive and restricted to an area supplied by a major coronary artery, can be a helpful pathologic marker of myocardial ischemia, particularly in sudden deaths without any other histologic findings.