Cardiology : Pulmonary Atresia with intact ventricular septum

Pulmonary Atresia with intact ventricular septum. As in Pulmonary Atresia with VSD, this defect is also associated with complete obstruction of the Pulmonary Artery. However, as there is no associated VSD, blood is diverted from the right atrium to the left atrium via the Foramen Ovale. The right ventricle (RV) is usually small (Hypoplastic), though its wall may be thickened (Hypertrophied).

https://www.rch.org.au/cardiology/heart_defects/Pulmonary_Atresia_with_intact_ventricular_septum/