Severe congenital tricuspid incompetence in the neonate.

Five neonates with congenital tricuspid incompetence due to severe tethering of the tricuspid valve to the right ventricle by abnormal chordal and papillary muscle attachments are described. The abnormality was called tricuspid valvular dysplasia (TVD) if the basal insertion of the valve was normal and the Ebstein malformation if it was displaced into the sinus portion of the ventricle. In the two infants with isolated TVD and severe tricuspid regurgitation the functional obstruction to right ventricular outflow (ORVO) produced by the high perinatal pulmonary vascular resistance (PVR) made the exclusion of pulmonary atresia difficult, despite selective right ventricular angiocardiography. In three infants the tricuspid valvular abnormality was associated with organic ORVO; pulmonary atresia in two and critical pulmonary valve stenosis in one. In the two infants with pulmonary atresia and intact ventricular septum (IVS) the severe tricuspid incompetence produced a clinical, radiological and hemodynamic profile which was clearly different from that usually seen in infants with pulmonary atresia and IVS and a normal right ventricular cavity (type 2 of Greenwold).