PULMONARY VALVE ATRESIA WITH INTACT VENTRICULAR SEPTUM.

In this cardiac malformation there is complete atresia of an otherwise well-formed pulmonary valve. The ventricular septum is intact; the right ventricular cavity is unusually small and the free wall is thick; the tricuspid valve annulus is usually small and the leaflets hypoplastic. The anomaly is to be distinguished from main pulmonary artery atresia with ventricular septal defect (severe tetralogy of Fallot or "pseudotruncus") and from severe pulmonary valve stenosis.