Using echocardiography, we identified 21 patients with a syndrome that included severe concentric cardiac hypertrophy, a small left ventricular cavity, and supernormal indexes of systolic function without concurrent medical illness or ischemic heart disease. Thirteen of the patients presented with dyspnea or chest pain. All patients studied had a history of hypertension and were compared with normotensive controls matched for age and sex. The patients were elderly (mean age, 73.3 years), predominantly female (16 patients), and mostly black (15 patients). Their cardiac function was characterized by excessive left ventricular emptying (ejection fraction on two-dimensional echocardiography [patients vs. controls], 79 +/- 4 vs. 59 +/- 5 per cent, P less than 0.001) and abnormal diastolic function as manifested by a prolonged early diastolic filling period (279 +/- 25 vs. 160 +/- 45 msec, P less than 0.001) and reduced peak diastolic dimension increase (11 +/- 4 vs. 16 +/- 5 cm per second, P less than 0.05). In spite of the clinical presentation of heart failure, all of 9 patients receiving either beta-receptor antagonists or calcium-channel blocking agents obtained symptomatic relief, whereas 6 of 12 patients receiving vasodilator medications had severe hypotensive reactions, including one death. We conclude that this unique subset of hypertensive patients has a clinical syndrome that warrants recognition and tailored management.