pulmonary atresia

pulmonary atresia [L, pulmoneus, lungs; Gk, a + tresis, without perforation] , a congenital heart defect of the right ventricular outflow tract. One form consists of an intact ventricular septum with an interatrial communication and a persistent patent ductus arteriosus. A more extreme form is the four-defect tetralogy of Fallot.