Pulmonary Stenosis

How Does Pulmonary Stenosis Affect the Heart?

The pulmonary valve acts like a one-way door that allows blood to leave the heart and go to the lungs to get oxygen. When this valve becomes too narrow, it causes:

• Extra Work for the Heart: The heart’s right side must pump harder to push blood through the small opening.
• Thickening of the Heart Muscle: The heart muscle can become thicker (called hypertrophy) from working too hard over time.
• Reduced Blood Flow to the Lungs: Less blood reaches the lungs, so there’s less oxygen in the blood that gets sent to the rest of the body.
• Possible Symptoms: If not treated, it can cause shortness of breath, tiredness, or a bluish tint to the skin (cyanosis) due to a lack of oxygen in the blood.

What Causes Pulmonary Stenosis?

The main cause of pulmonary stenosis is a problem during the baby’s development in the womb, but other causes can happen later in life. Possible causes include:

• Congenital Heart Defect: The valve may not develop properly before birth, making it too narrow or having thick, stiff leaflets that don’t open fully.
• Genetic Conditions: Conditions like Noonan syndrome can increase the risk of pulmonary stenosis.
• Infections: In rare cases, infections like rheumatic fever or heart infection (endocarditis) can cause scarring and narrowing of the valve.

Symptoms of Pulmonary Stenosis in Children

Many children with mild pulmonary stenosis have no symptoms and only discover the condition during a routine check-up. For moderate to severe cases, symptoms may include:

• Heart Murmur: A “whooshing” sound heard with a stethoscope as blood flows through the narrow valve.
• Shortness of Breath: Difficulty breathing, especially during play or physical activity.
• Tiredness and Fatigue: Feeling very tired, especially after activity, as the heart struggles to pump enough oxygen-rich blood.
• Chest Pain: Discomfort in the chest, especially during activity.
• Fainting (Syncope): Passing out, often during exercise or sudden physical activity.
• Cyanosis: A bluish tint to the skin, lips, or fingernails due to low oxygen in the blood.

How is Pulmonary Stenosis Diagnosed?

If a doctor suspects pulmonary stenosis, they will listen to the heart for a murmur and may order these tests:

• Echocardiogram (Echo): An ultrasound of the heart that shows how well blood flows through the valve.
• Electrocardiogram (ECG): This test checks the heart’s electrical activity to see if it’s under extra strain.
• Chest X-ray: This can show if the heart is enlarged.
• Cardiac MRI: This test gives a detailed image of the heart’s structure.
• Cardiac Catheterization: Sometimes, a thin tube is inserted into the heart to measure pressure and see how well the valve works.

How is Pulmonary Stenosis Treated?

Treatment depends on how narrow the valve is and how well the heart pumps. Options include:

• Monitoring: If the stenosis is mild, your child may only need regular check-ups with a cardiologist to track their heart health.
• Balloon Valvuloplasty is a minimally invasive procedure in which a balloon is placed into the valve and inflated to widen the opening. It’s a common treatment for children and can often avoid surgery.
• Surgery: If the valve is too thick or deformed, surgery may be necessary to repair or replace it.

How Can Parents Support Their Child with Pulmonary Stenosis?

If your child has pulmonary stenosis, here’s how you can support them:

• Keep Up with Check-Ups: Regular cardiology visits ensure the condition is monitored over time.
• Encourage Physical Activity: Your child's doctor will let you know if any sports or physical activity restrictions are needed. Most children with mild pulmonary stenosis can play normally.
• Watch for Symptoms: Look for signs like shortness of breath, tiredness, or fainting, and contact a doctor if you experience any of them.
• Maintain Good Oral Health: Good dental hygiene is essential because oral infections can spread to the heart in children with heart defects.

What Happens if Pulmonary Stenosis is Untreated?

If left untreated, severe pulmonary stenosis can cause:

• Heart Muscle Strain: The right side of the heart may thicken (right ventricular hypertrophy), making it harder for the heart to pump blood.
• Right Heart Failure occurs when the heart becomes unable to pump effectively over time, leading to swelling in the belly, ankles, or legs.
• Arrhythmias: Irregular heartbeats may develop if the heart is under too much strain.
• Low Oxygen Levels: Blood with less oxygen may circulate around the body, causing cyanosis (bluish skin or lips).

Can Pulmonary Stenosis be Prevented?

Since pulmonary stenosis is often a congenital (present at birth) condition, it can't always be prevented. However, parents can reduce some risk factors with these steps:

• Prenatal Care: Good prenatal care, including healthy eating, avoiding harmful substances, and taking folic acid, may reduce the risk of congenital heart defects.
• Genetic Counseling: Families with a history of heart defects or genetic conditions like Noonan syndrome may consider genetic counselling before having children.
• Preventing Infections: Good oral hygiene can help prevent endocarditis, which can cause valve problems. Prompt treatment of strep throat can prevent rheumatic fever, another risk factor for valve damage.

Types of Pulmonary Stenosis

Pulmonary stenosis can happen in different parts of the pulmonary valve or artery, including:

• Valvular Stenosis: The most common type, where the valve's leaflets are thick or fused, limiting blood flow.
• Subvalvular Stenosis: The muscle below the valve is thickened, causing narrowing.
• Supravalvular Stenosis: The narrowing happens just above the pulmonary valve, affecting the pulmonary artery.

Outlook for Children with Pulmonary Stenosis

With modern treatment options like balloon valvuloplasty and regular monitoring, most children with pulmonary stenosis live healthy, active lives. Mild cases may not need treatment, and more severe cases can often be managed with procedures or surgery. After treatment, children can usually return to normal activities, but regular check-ups with a cardiologist are important to ensure the heart stays healthy.



If you have concerns about your child’s heart health or want more information on pulmonary stenosis, speak with a paediatric cardiologist. Early detection and treatment can greatly improve children's chances of leading healthy, active lives.