Pulmonary stenosis is a congenital heart disorder where blood flow is blocked between the right ventricle and pulmonary artery. The most common form, pulmonary valve stenosis, is a blockage in the valve that separates the ventricle and the arteries, the pulmonary valve. The Problem
In a healthy heart, the right atrium fills with blood from the body and then passes it to the right ventricle. The ventricle then passes it to the pulmonary artery, which carries it to the lungs. The blood becomes oxygenated in the lungs and re-circulates throughout the body. The pulmonary valve is the valve between the right ventricle and the pulmonary artery. If this valve is obstructed, blood cannot properly flow to the lungs.
Usually, the problem is with the leaflets in the valve. In a healthy valve, three flexible leaflets move aside easily to enable the blood to pass. In a defective valve, the leaflets may be molded together or stiffened, so they are not as pliable as usual. A narrowing of the valve could also obstruct blood flow.
PVS prevents enough blood from flowing to the lungs. Furthermore, the ventricle has to work harder to compensate for the obstruction. This can cause it to enlarge, a condition known as hypertrophic cardiomyopathy. This shouldn’t present a problem in itself, but is a symptom of the underlying problem, the defect. PVS can also cause blood to pass straight from the right atrium to the left, which produces a symptom, explained below, called cyanosis. PVS does not usually cause heart failure.
