Current concepts of the pathogenesis and treatment of hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM), a relatively common genetic disease, is the most common cause of sudden cardiac death (SCD) in young people. The estimated prevalence is 1 in 500. The proportion of individuals inheriting the disease (familial) as opposed to developing a de novo mutation (sporadic) remains to be determined. Nevertheless, because all HCM is genetic in origin, even individuals with the sporadic form will transmit the gene to their offspring and become part of the familial pool. Cases with outflow tract obstruction are referred to as hypertrophic obstructive cardiomyopathy (HOCM) and those without obstruction as HCM. Symptoms occur earlier and are more severe in patients with obstruction.1 The overall annual death rate in patients with HCM is estimated at 1%/year, whereas that in patients with HOCM is 2%/year, with the risk of stroke being 4-fold greater than it is in patients with HCM.1