The pulmonary valve controls blood flow from the right side of your heart into your lungs. It acts as a one-way gate between the right ventricle and the pulmonary artery, opening to let oxygen-poor blood move toward the lungs and closing to prevent that blood from leaking back into the heart. This open-close cycle happens with every single heartbeat, thousands of times a day, for your entire life.
How the Pulmonary Valve Works
The pulmonary valve has three thin leaflets (sometimes called cusps or flaps) that respond to pressure changes inside the heart. When the right ventricle contracts, the pressure pushes the leaflets open, and blood flows out through the pulmonary artery toward the lungs. When the ventricle relaxes, the pressure drops, and the leaflets snap shut to seal the opening. This prevents blood from flowing backward into the ventricle.
That closure actually produces a sound your doctor can hear with a stethoscope. The second heart sound, often written as “S2,” has two components: the aortic valve closing first, then the pulmonary valve closing a split second later. The pulmonary valve’s contribution is softer and best heard at the upper left edge of the breastbone, near the second rib.
Where It Fits in the Heart’s Blood Flow
Your heart has four valves, and the pulmonary valve sits at the exit of the right ventricle. Blood arriving from the body is low in oxygen. It enters the right atrium, passes through the tricuspid valve into the right ventricle, and then gets pumped through the pulmonary valve into the pulmonary artery. From there, it travels to the lungs, picks up fresh oxygen, and returns to the left side of the heart for distribution to the rest of the body.
The pulmonary valve is the only valve standing between the heart and the lungs. Without it working properly, the right ventricle would have to work harder with every beat, either pushing blood through a narrowed opening or re-pumping blood that leaked backward.
Pulmonary Valve Stenosis
Stenosis means the valve is too narrow, restricting how much blood can pass through. This is usually a congenital condition, meaning it’s present from birth. The severity varies widely. Many people with mild stenosis have no symptoms at all and may never know they have it unless a doctor detects a heart murmur during a routine exam.
More significant narrowing tends to show up during physical activity first, because that’s when the heart needs to move more blood. Symptoms can include shortness of breath during exercise, fatigue, chest pain, and a whooshing sound (heart murmur) that a stethoscope picks up easily. The more restricted the blood flow, the more pronounced the symptoms become.
Pulmonary Valve Regurgitation
Regurgitation is the opposite problem: the valve doesn’t close tightly enough, so blood leaks backward into the right ventricle. A trace amount of leakage is actually normal, especially as you get older. Nearly everyone has some degree of it, and mild to moderate regurgitation typically doesn’t affect life expectancy or require treatment.
Severe regurgitation is a different story. The two most common causes are high blood pressure in the lung arteries (pulmonary hypertension) and congenital heart defects. One particular defect called tetralogy of Fallot often leads to regurgitation, especially after surgical repair in childhood. When leakage is severe, the right ventricle has to handle a larger volume of blood with each beat. It can compensate for years, sometimes decades, but eventually the extra workload can weaken the heart muscle.
How a Damaged Pulmonary Valve Gets Fixed
When the pulmonary valve is too damaged to function, it can be replaced. The traditional approach is open-heart surgery, where a surgeon removes the faulty valve and stitches in a new one.
A less invasive option now exists: transcatheter pulmonary valve replacement. Instead of opening the chest, a doctor threads a catheter (a thin, flexible tube) through a blood vessel, usually in the leg, and guides a new valve into position inside the old one. Several devices are currently approved for this approach, and the technique has expanded in recent years to treat patients with different types of anatomy, including those born with naturally large outflow tracts that were previously difficult to treat with catheter-based methods.
The choice between surgical and catheter-based replacement depends on the specific anatomy involved, the condition of surrounding heart structures, and whether the patient has had previous heart surgery. For many patients, particularly those who have already undergone one or more open-heart operations, the catheter approach avoids the risks and recovery time of repeat surgery.