Clinical characteristics and outcomes of hypertrophic cardiomyopathy in Taiwan - A tertiary center experience

Background: Most information concerning hypertrophic cardiomyopathy has been derived from western countries and Japan. Hypothesis: Patients with hypertrophic cardiomyopathy in Taiwan may have a distinct morphology and clinical picture. Methods: Information from 163 consecutive patients with hypertrophic cardiomyopathy at a medical center in Taiwan from 1990 through 2005 was retrospectively collected. The diagnosis of hypertrophic cardiomyopathy required echocardiographic demonstration of left ventricular hypertrophy (wall thickness > 15 mm during diastole) in a specific region or with diffuse distribution. Follow-up information was obtained from medical records. Results: Among 163 patients (male, 52%), the mean follow-up period was 5.3 +/- 4.1 years. Men had nearly a threefold increase in prevalence of apical hypertrophic cardiomyopathy (23.8% vs. 8.9%, p = 0.03), younger onset of initial evaluation (57.2 +/- 12.9 vs. 64.8 +/- 11.3, p < 0.001), and lower prevalence of hypertrophic obstructive cardiomyopathy (33.3% vs. 63.3%, p < 0.001) compared to women. Fifty-eight patients (35.6%) experienced cardiovascular events, of which pulmonary edema and paroxysmal atrial fibrillation were the most common (19.7% and 12.3%, respectively). The annual cardiovascular mortality rate was 0.8%. In multivariate analysis, left ventricular outflow obstruction [odds ratio (OR): 4.92, p = 0.001], atrial fibrillation (OR: 3.53, p = 0.014), and female gender (OR: 2.99, p = 0.043) were independent predictors of mortality. Conclusions: Hypertrophic cardiomyopathy did not significantly increase cardiovascular mortality rate, but over one-third of patients with hypertrophic cardiomyopathy experienced cardiovascular events. High prevalence of left ventricular outflow obstruction especially in elderly women was observed. Left ventricular outflow obstruction, atrial fibrillation, and female gender were predictors of mortality.