Hypertrophic cardiomyopathy (HCM) has been of great interest to clinicians because of its diverse clinical, morphologic, pathophysiologic and molecular genetic manifestations. We investigated the frequencies and clinical manifestations according to the types in Maron's classification of HCM.

Patients with HCM who were seen at our institution from June 1999 to July 2001 were retrospectively reviewed. Echocardiographic patterns were classified by Maron's classification.

Of 62 patients (M/F=39/23, 56±14.8 years), 6 patients (9.7%) were type I (relatively mild left ventricular hypertrophy confined to the anterior portion of ventricular septum), 10 patients (16.1%) were type II (hypertrophy of the anterior and posterior septum in the absence of free-wall thickening), 25 patients (40.3%) were type III (diffuse hypertrophy of substantial portion of both the ventricular septum and anterolateral free wall), 1 patients (1.6%) were type IV (hypertrophy in the posterior septum or anterolateral free wall) and 20 patients (32.3%) were type V (apical hypertrophy). Compared with western countries in which the type III was most common, type III was also most common in Korea, but type V was more common in Korea. Systolic anterior motion of mitral leaflet (SAM) were noted in 12 patients in which 10 patients had type III. 43 of 62 patients (69.4%) had chest pain (33.9%), dyspnea on exertion (30.6%), palpitation (1.6%) and syncope (3.2%). 19 of 62 patients (30.6%) had no subjective symptoms, and there was no significant statistical difference between types. Three of 62 patients had anomalous insertion of papillary muscle at mitral valve.

The most common type was type III, and SAM was found mostly in type III. Anomalous insertion of papillary muscle was noted in 3 out of 62 cases. There was no differences in subjective symptom between the types.