Stenotic semilunar valve in persistent truncus arteriosus.

The clinical, hemodynamic, and pathologic findings in two newborn infants with persistent truncus arteriosus and stenosis of the truncal valve are described. In one case the anatomic features of the basic condition were classic, with a dysplastic semilunar valve which was mainly stenotic and also incompetent, while in the other the truncus arteriosus arose exclusively from the right ventricle and was almost exclusively stenotic. A ventricular septal defect was the only outlet for the left ventricle. In this case, mitral stenosis was also present and associated with a left-to-right shunt at the atrial level.