[Muscular obstruction of the right ventricular outflow tract. Subvalvular pulmonary stenosis or hypertrophic cardiomyopathy?].

A case is reported of right ventricular outflow obstruction caused by hypertrophic cardiomyopathy. The pressure gradient between the inflow tract and the outflow tract of the right ventricle was 84 mm Hg. Resection of the hypertrophic muscle bundles practically eliminated the obstruction leaving only an insignificant subvalvular gradient of 2 mm Hg. Histologic examination revealed cardiac muscle cell hypertrophy and disorganization.