[Hypertrophic cardiomyopathy: spontaneous course].

Hypertrophic cardiomyopathy is a relatively rare (prevalence approximately 0.2%), primary myocardial disorder with an autosomal pattern of inheritance, characterized by mostly asymmetric left ventricular hypertrophy with myocyte and myofibrillar disarray. To date, about 34 mutations of the beta-cardiac myosin heavy chain gene have been described and shown to have prognostic implications. The disease has an annual mortality rate of 3%, related to both sudden cardiac death and progressive systolic dysfunction. Not only diastolic but also progressive systolic dysfunction with cavity dilatation occurs in a minority of patients with severe hypertrophy during the long-term course. Sudden death often occurs in young, asymptomatic or mildly symptomatic patients. The degree of hypertrophy and the presence of a pressure gradient are of little prognostic significance. Nonsustained ventricular tachycardia is associated with a poor prognosis in the presence of a history of syncope.