756-3 Management and Prognosis of Asymptomatic Patients with Hypertrophic Cardiomyopathy

The clinical course of hypertrophic cardiomyopathy (HCM) is extremely heterogeneous; some patients develop severe symptoms of heart failure, some die suddenly, but many remain asymptomatic throughout life. The prognosis of patients who are asymptomatic at initial examination, however, has never been investigated systematically in a large study population. We examined the clinical course of all the patients with HCM who were evaluated in our department during 10 years and were asymptomatic or had only mild symptoms at initial examination. A total of 89 patients were followed for a mean of 4.9 yrs (0.3–10.8). Of these 89 patients, 50 (56%) were not treated with cardioactive medications during follow up. Annual mortality was 0.4% (95% confidence interval 0.1–1.4); only 2 patients died, both showing progressive deterioration before death. Seventy-nine patients (89%) remained clinically stable during follow up, 3 developed severe symptoms (functional class III), and 5 did not progress to class III but experienced sustained ventricular tachycardia or syncope. Echocardiographic assessment of cardiac morphology showed that the 2 patients who died were in the small group of 8 patients with particularly marked hypertrophy (≥30mm) at initial examination. In conclusion, our results show that cardiac mortality is low in patients with HCM who are asymptomatic or have only mild symptoms, and that clinical deterioration usually occurs gradually. In the absence of data showing that therapy prevents cardiac death or delays disease progression in HCM, our results suggest that treatment should be used only for alleviation of symptoms