The pulmonary valve atresia/critical valve stenosis is a congenital heart defect which develops during the fetal life and is characterized by a wide spectrum of severity as result of the blood flow remodeling process of the right ventricle outflow. In the atretic valve there is absence of communication between the right ventricle outflow and the size of the pulmonary trunk and the right ventricle can vary considerably. Very often massive hypertrophy of the right parietal wall contribute substantially to the hypoplasia of the ventricular cavity. The tricuspid valve is also affected, been very often diminutive and dysplastic.Three types of pulmonary valve morphology can be identified: type a: pulmonary valve atresia with imperforate valve; type b: critical pulmonary valve stenosis with three dysplastic valve leaflets; type c: critical pulmonary valve stenosis with bicuspid or unicuspid valve.