Pulmonary valve stenosis signs and symptoms vary, depending on the extent of the obstruction. People with mild pulmonary stenosis usually don't have symptoms. Those with more significant stenosis often may first notice symptoms while exercising.

Pulmonary valve stenosis signs and symptoms may include:

• Heart murmur — an abnormal whooshing sound heard using a stethoscope, caused by turbulent blood flow
• Fatigue
• Shortness of breath, especially during exertion
• Chest pain
• Loss of consciousness (fainting)

Pulmonary valve stenosis usually occurs when the pulmonary valve doesn't grow properly during fetal development. Babies who have the condition may have other congenital heart abnormalities, as well. It's not known what causes the valve to develop abnormally.

Normal pulmonary valve anatomy

The pulmonary valve is made up of three thin pieces of tissue called cusps that are arranged in a circle. With each heartbeat, the valve opens in the direction of blood flow — into the pulmonary artery and continuing to the lungs — then closes to prevent blood from flowing backward into the heart's right ventricle.

What happens in pulmonary valve stenosis

One or more of the cusps may be defective or too thick, or the cusps may not separate from each other properly. If this happens, the valve doesn't open correctly, restricting blood flow.

Other contributing conditions

Sometimes other medical conditions or having an artificial valve can cause the condition.

• Carcinoid syndrome. This syndrome — a combination of signs and symptoms, including flushing of the skin and diarrhea — results from the release of a chemical, serotonin, from growths called carcinoid tumors in the digestive system.
• Rheumatic fever. This complication of an infection caused by streptococcus bacteria, such as strep throat, may injure the heart valves.

Because pulmonary valve stenosis usually develops before birth, there aren't many known risk factors. However, certain conditions and procedures can increase your risk of developing pulmonary valve stenosis later in life, including:

• Carcinoid syndrome
• Rheumatic fever
• Noonan syndrome
• Pulmonary valve replacement

Pulmonary stenosis may be associated with the following:

• Infection. People with heart valve problems, such as pulmonary stenosis, have a higher risk of developing bacterial infections in the inner lining of the heart (infective endocarditis) than people without heart valve problems.
• Heart-pumping problems. In severe pulmonary stenosis, the heart's right ventricle must pump harder to force blood into the pulmonary artery. Pumping of the right ventricle against increased pressure causes the muscular wall of the ventricle to thicken (right ventricular hypertrophy). Eventually, the heart becomes stiff and may weaken.
• Heart failure. If the right ventricle is unable to pump efficiently, heart failure develops. This results in swelling of the legs and abdomen and can cause fatigue and shortness of breath.
• Irregular heartbeat (arrhythmia). People with pulmonary stenosis are more likely to have an irregular heartbeat. Unless the stenosis is severe, irregular heartbeats associated with pulmonary stenosis usually aren't life-threatening.