PREVALENCE OF HYPERTROPHIC CARDIOMYOPATHY IN AN OUTPATIENT POPULATIONREFERRED FOR ECHOCARDIOGRAPHIC STUDY

Although hypertrophic cardiomyopathy (HC) is believed to be a relative ly uncommon cardiac disease, the frequency with which it occurs in the general or cardiac Population has not been defined. To address this i ssue, the patient population of a community-based echocardiography lab oratory was used to assess the prevalence of HC in 714 consecutively s tudied outpatients with (or suspected of having) heart disease. The mo st common cardiac disease identified was mitral valve prolapse (73 pat ients [10%]), and HC was present in 4 patients (0.5%). Ages were 50 to 69 years. Maximal left ventricular wall thicknessess were 15 to 22 mm (mean 19); only 1 had evidence of obstruction to left ventricular out flow by virtue of marked mitral valve systolic anterior motion. Before echocardiographic study, each of the 4 patients with HC had signs or symptoms of cardiac disease, but the correct diagnosis had not been su spected. Of 11 other patients who were referred for echocardiographic study because of a clinical suspicion of HC, none proved to have this disease. The present study demonstrates that HC is a particularly unco mmon disease entity occurring in about 0.5% of an unselected outpatien t population referred for echocardiographic study.