Pulmonary valve
stenosis is a condition in which a deformity on or near your pulmonary valve
narrows the pulmonary valve opening and slows the blood flow. The pulmonary
valve is located between the lower right heart chamber (right ventricle) and
the pulmonary arteries. Adults occasionally have pulmonary valve stenosis as a
complication of another illness, but mostly, pulmonary valve stenosis develops
before birth as a congenital heart defect.

Pulmonary valve
stenosis ranges from mild and without symptoms to severe. Mild pulmonary
stenosis doesn't usually worsen over time, but moderate and severe cases may
worsen and require surgery. Fortunately, treatment is generally highly
successful, and most people with pulmonary valve stenosis can expect to lead
normal lives.