The case of a previously health 17-year-old youth who presented a fatal cerebral infarct is described. A localized defect in the anterior left ventricular myocardium with overlying thrombus, and left ventricular hypertrophy were found at necropsy. An old infarct was found in the left kidney. There were no signs of ischaemic or inflammatory heart disease. The possible origins of the lesion are discussed.