Hypertrophic cardiomyopathy: the search for obstruction.

Hypertrophic cardiomyopathy is a fascinating disease entity in which hypertrophy of the myocardium occurs, primarily as a result of mutations of genes encoding the cardiac sarcomere.1–3 Our knowledge of patients with this unique disease of the heart muscle has advanced significantly. Once thought to be a rare malignant disease with a high risk of sudden death, population studies have revealed hypertrophic cardiomyopathy to be a more common disease with a benign outlook in the majority of affected patients.4 Hypertrophic cardiomyopathy is now recognized to comprise a wide spectrum of disease processes, with varying genetics, anatomy, clinical presentation, and prognosis. The dynamic left ventricular outflow tract obstruction that was initially the hallmark of hypertrophic cardiomyopathy continues to be a source of controversy.