Hypertrophic nonobstructive cardiomyopathy as a cause of angina pectoris.

Four patients with severe classic angina pectoris and no evidence of myocardial infarction are described. All had ECG changes compatible with myocardial ischemia. Coronary arteriography showed normal coronary arteries (except for minor narrowing in one patient) and marked hypertrophy of the left ventricle without left ventricular outflow tract obstruction. The diagnosis of hypertrophic nonobstructive cardiomyopathy was confirmed by the presence of small left ventricular diastolic and systolic volumes with a supernormal ejection fraction indicative of a hypercontractile state of the left ventricle. Treatment with beta-blocking agents reduced myocardial work, improved diastolic compliance and decreased patients' anginal symptoms. Hypertrophic nonobstructive cardiomyopathy is an important cause of typical angina pectoris in patients who have normal coronary arteries on coronary angiography.