Progression from hypertrophic cardiomyopathy to dilated cardiomyopathy.

The incidence of hypertrophic cardiomyopathy progressing to dilated cardiomyopathy is rare. A patient diagnosed at age 22 and followed for 24 years who progressed to a dilated cardiomyopathy with severe congestive heart failure is reported. Left ventricular dilatation in hypertrophic cardiomyopathy may be due to a complication of surgery, beta-blocker therapy, or myocardial infarction. It may also represent the natural history in a subset of patients with hypertrophic cardiomyopathy.