Pulmonary stenosis is a narrowing of the pulmonary valve. Normally the pulmonary valve opens to let low-oxygen blood flow from the right ventricle to the lungs where the blood is oxygenated. Because of the narrowing, the right ventricle has to pump harder to get past the stenotic valve. This can sometimes lead to enlargement of the right ventricle. With pulmonary stenosis, problems with the pulmonary valve make it harder for the leaflets to open and permit blood to flow forward from the right ventricle to the lungs. In children, these problems can include:
- a valve that only has one or two leaflets instead of three.
- a valve that has leaflets that are partially fused together.
- a valve that has thick leaflets that do not open all the way.