Echocardiographic evidence of outflow tract obstruction in Pompe's disease (glycogen storage disease of the heart).

A 7 month old black female infant with the clinical findings of Pompe's disease is presented. The diagnosis of an infiltrative myocardiopathy with left ventricular outflow tract obstruction presenting with a pronounced systolic anterior motion of the anterior mitral valve leaflet was made by echocardiography. This diagnosis was confirmed by cardiac catheterization and angiocardiography. Pathologic findings were consistent with Pompe's disease (type II glycogen storage disease). The presence of systolic anterior motion of the mitral valve in this patient suggests that this finding is not pathognomonic of idiopathic hypertrophic subaortic stenosis.