Intramural coronary artery dysplasia of the ventricular septum and sudden death.

We report four cases of sudden unexpected death in three males and one female aged 12 to 31 years. Death occurred during exercise in three of four cases, and there was no history of sudden death or previous cardiac history in any patient. At autopsy, there was marked intramural coronary artery dysplasia of the ventricular septum, accompanied in three of the four cases by myocardial fibrosis. The arterial dysplasia was characterized by severe medial thickening with smooth muscle cell disorganization and marked luminal narrowing. There was no evidence of myofiber disarray or asymmetric septal hypertrophy to suggest hypertrophic cardiomyopathy. Other than an ostium secundum type atrial septal defect in one case, there were no associated cardiac or extracardiac lesions found at complete autopsy of these individuals. We conclude that small vessel disease of intramural coronary arteries of the ventricular septum may be an isolated finding leading to sudden cardiac death in young adults.