We investigated the prevalence of hypertrophic cardiomyopathy (HC) and its association with mitral anular calcium (MAC) detected by Doppler echocardiography in 379 unselected elderly patients in a long-term health care facility. HC was present in 17 of 379 patients (4 percent). Of 17 patients with HC, ten (59 percent) had asymmetric septal hypertrophy, and seven (41 percent) had idiopathic hypertrophic subaortic stenosis with resting gradients of 20 to 110 mm Hg across the left ventricular outflow tract. The mean age of patients with HC was 85 +/- 7 years compared with 82 +/- 8 years in patients without HC (difference not significant). MAC was present in 13 of 17 patients (76 percent) with HC and in 176 of 362 (49 percent) without HC (p less than 0.025).