What is pulmonary stenosis?

Pulmonary stenosis is narrowing of the valve between the right ventricle and pulmonary artery. Pulmonary artery is the large blood vessel carrying blood to the lungs for oxygen enrichment. Right ventricle is the right lower chamber of the heart which pumps blood to the lungs. Pulmonary valve prevents backflow of blood from the pulmonary artery into the right ventricle when it relaxes after a contraction.