Comparison of the clinical features of apical hypertrophic cardiomyopathy versus asymmetric septal hypertrophy in Korea

Background: We sought to test whether patients with apical hypertrophic cardiomyopathy (APH) have different clinical features compared to those with typical asymmetric septal hypertrophy (ASH). Methods: Among 32,534 patients who underwent routine echocardiography at Asan Medical Center from January 2000 to December 2001, 305 patients (0.9%), who were finally diagnosed with hypertrophic cardiomyopathy (HCMP), were evaluated. The type of HCMP was classified according to the echocardiographic findings. Results: ASH was the most frequent type (n=160, 53%, group I), and APH was the second most frequent (n=91, 30%, group II). Mean age (60.8±10 vs. 48.2±14 years, p<0.001) and prevalence of hypertension (32% vs. 19%, p=0.022) were significantly higher in group II than in group I. Family history of HCMP (4.4% vs. 0% p=0.043) and sudden cardiac death (8.8% vs. 1.1% p=0.014) was more prevalent in group I. During the follow-up period of 32.0± 37.2 months, cardiac events occurred at a significantly higher rate in group I (25.5% vs. 8.8%, p=0.003). Conclusion: APH comprises a significant proportion of HCMP in Korea and patients with APH show different clinical features compared to those with ASH.