Report of the WHO/ISFC task force on the definition and classification of cardiomyopathies.

HYPERTROPHIC CARDIOMYOPATHYt This condition is characterised by disproportionate hypertrophy of the left ventricle and occasionally also of the right ventricle which typically involves the septum more than the free wall but occasionally is concentric. Typically the left ventricular volume is normal or reduced. Systolic gradients are common. Inheritance is usually by an autosomal dominant gene with incomplete penetrance. Characteristic morphological changes, usually most severe in the septum, have been described.