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Autopsy studies in victims of sudden coronary death revealed intramyocardial platelet aggregates with microscopic myonecrosis downstream from ruptured atherosclerotic plaques. Ruptured plaques usually manifest angiographically as irregularly bordered (type II) lesions. To investigate the possible pathogenic role of ruptured plaques in arrhythmic death, we analyzed clinical, angiographic, and electrophysiologic data from 49 survivors of cardiac arrest without acute myocardial infarction. All patients had greater than or equal to 50% stenoses of greater than or equal to one coronary artery; 16 had type II morphology, and 33 did not. Type II morphology was more prevalent in patients without inducible sustained monomorphic ventricular tachycardia (11 of 22 or 50%) than in those with it (five of 27 or 19%), p less than 0.05, and patients without akinetic or dyskinetic segments (eight of 14 or 57%) than in those with them (eight of 34 or 24%), p less than 0.06. Thus type II morphology is more prevalent in patients without a demonstrable anatomic and/or electrophysiologic substrate for reentrant ventricular tachycardia, indirectly implicating ruptured plaques in the pathogenesis of cardiac arrest in this subset of patients.

Angiographically irregular coronary stenoses usually represent plaque rupture with or without superimposed thrombi. Long-segment coronary stenoses with diffuse irregularities (type IIB morphology) have been shown to be more prevalent than focal irregular lesions (type IIA morphology) in survivors of cardiac arrest without acute myocardial infarction. To further understand the pathogenetic importance of type IIB morphology, the clinical and angiographic characteristics in 59 such patients were analyzed. Type IIB lesions accounted for 63% of all type II lesions. Type IIB patients were older than type IIA patients (p less than 0.05). There was a tendency for type IIB morphology to be associated with more extensive disease than other types of lesion morphology (p less than 0.10). Type IIB morphology probably reflects more advanced atherosclerosis. Platelet microemboli may precipitate spasm and/or acute ischemic ventricular tachyarrhythmias. It is possible that long-segment coronary ulcerations are associated with a higher risk for local coronary thromboembolism, and hence with sudden death, than focal lesions.