Pulmonary atresia with ventricular septal defect (PA-VSD) is a cyanotic congenital heart disease characterized by underdevelopment of the right ventricular (RV) outflow tract (ie, subpulmonary infundibulum) with atresia of the pulmonary valve, a large ventricular septal defect (VSD), and overriding of the aorta. In the past, this anomaly was termed pseudotruncus or truncus arterious type 4.
Pulmonary atresia with ventricular septal defect demonstrates a wide spectrum of severity, depending on the degree of pulmonary artery development. Pathologically, pulmonary atresia with ventricular septal defect is frequently considered the most severe end of the spectrum of tetralogy of Fallot (TOF), but whether pulmonary atresia with ventricular septal defect and TOF should be treated as 2 distinct entities is controversial. In patients with the standard type of TOF with pulmonary atresia, pulmonary arteries are usually normal in size with normal peripheral pulmonary arborization, which is unlike pulmonary atresia with ventricular septal defect. In addition, systemic-to-pulmonary collateral vessels are not as well developed in patients with TOF with pulmonary atresia as they are in patients with pulmonary atresia with ventricular septal defect.