Acute coronary syndrome as a cause of sudden death in patients with old myocardial infarction: a pathological analysis.

Old myocardial infarction (OMI) is one of the most important pathological manifestations in sudden cardiac death. Fatal arrhythmia arising from a fibrotic scar has been determined as the cause of death in most cases with old myocardial infarction. However, the significance of acute plaque disruption/thrombosis of the coronary arteries in those patients has not been investigated. We examined a series of 33 hearts from individuals with OMI who died suddenly during the period from 1998 to 2001. Detailed coronary pathological findings on these hearts indicated fresh or recent rupture of the coronary plaque with thrombosis in 18 cases (55%). As a result of comprehensive analysis, the sudden deaths were explained by acute coronary syndrome in 18 cases (55%), fatal arrhythmia in eight (24%), cardiac pump failure in five (14%), and other causes in two (6%) cases. Our findings revealed that a new coronary plaque rupture independent of the old infarct was a major cause of sudden cardiac death with OMI.