[Rapid progression of hypertrophic cardiomyopathy into a dilated form--unusual course in a young patient. A case report].

Hypertrophic cardiomyopathy is a disorder which primarily affects the myocardium. It is characterized by a hypertrophic left ventricle that shows normal systolic function but impaired diastolic relaxation. The most important complication of HCM, sudden cardiac death, is mainly responsible for a mortality of approximately 3.5% in childhood. While most patients remain asymptomatic for years, there are some reports about patients progressing from hypertrophic cardiomyopathy to a dilative form within years. We report on a boy who was at the age of twelve when hypertrophic cardiomyopathy was diagnosed first. He remained stable for the first years, but at the age of sixteen his cardiomyopathy progressed to a dilative form with reduced systolic function and severe cardiac failure. The possible pathogenesis is discussed and an overview of similar cases reported earlier is given.