Congenital left ventricular inflow obstruction evaluated by two-dimensional echocardiography.

Several forms of congenital heart disease that cause left ventricular inflow obstruction have similar M-mode findings, and frequently the exact anatomic diagnosis cannot be made by M-mode echocardiography alone. We examined five children with various forms of left ventricular inflow obstruction using two-dimensional echocardiography. The diagnosis was confirmed by cardiac catheterization and surgery in all five patients. In one patient with congenital mitral valve stenosis, a thick mitral valve with two papillary muscles was imaged. This patient was easily distinguished from a second child with parachute deformity of the mitral valve in whom a single papillary muscle arising from the left ventricular apex was seen. These two patients with mitral valve stenosis were easily differentiated from the three patients in whom the left ventricular inflow obstruction was caused by a membrane within the left atrium. The membrane could be seen in several spatial planes; however, we could not distinguish by two-dimensional echocardiography one child who had cor triatriatum from the other two patients who had a supravalvar mitral ring. Because of its spatial anatomic display, the two-dimensional echocardiogram provides information for a more detailed anatomic diagnosis in children with congenital left ventricular inflow obstruction.