Hypertensive hypertrophic cardiomyopathy may be a distinctive cardiac condition resulting from hypertension. Alternatively, this disease may represent the coincidence of a common disease, hypertension, with a relatively rare cardiomyopathy. A consecutive series of patients with hypertrophic cardiomyopathy and hypertension were studied and compared with age- and gender-matched patients with cardiomyopathy alone. Thirty-nine patients were identified as having hypertension; they ranged in age from 31 to 84 years (average 60 +/- 13); 82% were greater than 50 years old; 18 (46%) were women. When these patients were compared with the age-matched group with hypertrophic cardiomyopathy alone, there were no clinical or electrocardiographic differences between the two groups. By echocardiography, the hypertensive and nonhypertensive groups had a similar incidence of systolic anterior motion (77 versus 64%, respectively), mitral annular calcification (31 versus 31%), septal thickness greater than 20 mm (56 versus 46%) and outflow tract gradient greater than 20 mm (59 versus 67%). A posterior wall thickness greater than 13 mm was more frequent in the hypertensive group (54%) compared with the nonhypertensive group (31%) (p = 0.02). The findings show that hypertrophic cardiomyopathy with associated hypertension is a disease of the elderly. But, with the exception of thicker walls, the clinical and echocardiographic features of the patients with hypertension were indistinguishable from those of the age-matched and, hence, elderly group of patients with cardiomyopathy without hypertension. These findings suggest that hypertension may make hypertrophy worse, but that it is not the primary cause of the cardiomyopathy. Thus, the condition might be better termed "hypertrophic cardiomyopathy with hypertension."