Ebstein's malformation of the tricuspid valve in the neonate: Functional and anatomic pulmonary outflow tract obstruction

The clinical and physiologic data obtained in 4 infants with Ebstein's malformation and 2 with pulmonary atresia with intact ventricular septum and large volume right ventricle have been presented. These two conditions may be extremely difficult to differentiate in the neonatal period on clinical grounds alone, and catheterization and angiocardiographic studies are required for an accurate diagnosis. Functional pulmonary valve obstruction in neonates with Ebstein's malformation resulting from ineffective forward ejection of right ventricular blood and with little or no blood traversing a normal pulmonary valve has been demonstrated angiocardiographically. Anatomic obstruction of the right ventricular outflow tract by the large curtain-like, malaligned tricuspid valve leaflet has also been demonstrated. An accurate assessment of the anatomy and physiology of the pulmonary outflow tract is essential to therapeutic management.