Pulmonary Atresia with Ventricular Septal Defect (PA-VSD): Complete Guide for Parents
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
TL;DR
Pulmonary atresia with ventricular septal defect (PA-VSD) is a heart condition a baby is born with — a congenital heart defect. The pulmonary valve, which connects the heart to the lungs, isn't fully formed and stays closed, so blood cannot flow from the right ventricle to the lungs. A hole (the VSD) also connects the two pumping chambers. PA-VSD is life-threatening because the baby eventually does not get enough oxygen. Signs in newborns include blue or gray skin, fast breathing, tiredness, and poor feeding. Treatment starts right away and may include a catheter procedure with a stent, a shunt (such as the BT shunt), complete surgical repair, or staged unifocalization — followed by lifelong checkups with a congenital cardiologist.
Quick Answer
What is PA-VSD? A congenital heart defect in which the pulmonary valve never opens and a hole (VSD) connects the heart's two pumping chambers, so blood cannot reach the lungs normally. Is it serious? Yes — PA-VSD is life-threatening; a baby with it eventually doesn't get enough oxygen. When is it found? Typically during pregnancy or soon after birth. What are the signs? Blue or gray skin, fast breathing, tiredness, and not feeding well. Can it be fixed? Yes — one or more procedures or surgeries restore blood flow to the lungs. What happens long-term? Babies need regular checkups with a congenital cardiologist, a doctor trained in heart conditions present at birth.
What Is Pulmonary Atresia with Ventricular Septal Defect?
Pulmonary atresia (pronounced uh-TREE-zhuh) with ventricular septal defect, also called PA-VSD, is a heart condition a baby is born with. That makes it a congenital heart defect [1].
In pulmonary atresia, the valve between the heart and the lungs isn't fully formed. This valve is called the pulmonary valve. Because it stays closed, blood cannot flow from the right lower heart chamber — called the right ventricle — to the lungs. In PA-VSD, there is also a hole between the two pumping chambers of the heart, known as a ventricular septal defect (VSD) [1].
PA-VSD is life-threatening. A baby with pulmonary atresia eventually doesn't get enough oxygen. Treatment includes one or more procedures or surgeries to fix the heart [1].
Key fact: PA-VSD combines two problems at once — a pulmonary valve that never opens, and a hole between the heart's pumping chambers. Without treatment, the baby eventually does not get enough oxygen [1].
The rest of this guide explains what PA-VSD looks like in a newborn, what is known about why it happens, how doctors diagnose it, and the four treatment pathways that restore blood flow to the lungs.
Figure 1: In a normal heart, the open pulmonary valve sends blood from the right ventricle to the lungs. In PA-VSD, the valve stays closed and a hole (VSD) lets blood move between the pumping chambers.
PA-VSD at a Glance
What is it? A congenital heart defect present at birth
The two problems: Pulmonary valve stays closed + a hole (VSD) between the pumping chambers
Is it life-threatening? Yes — the baby eventually doesn't get enough oxygen
When is it usually found? During pregnancy or soon after birth
Main signs in newborns: Blue or gray skin, fast breathing, tiredness, poor feeding
Is the cause known? No — the cause of PA-VSD is not clear
Treatment timing: Right away, with one or more procedures or surgeries
Long-term care: Regular checkups with a congenital cardiologist
Symptoms of PA-VSD in a Newborn
Symptoms of PA-VSD may appear soon after a baby's birth [1]. The most important signs to watch for are [1]:
Blue or gray skin: A bluish or gray tint to the skin, lips, or nail beds — this change may be harder or easier to see depending on skin color
Fast breathing: Breathing faster than normal or shortness of breath
Tiredness: Lethargy, unusual sleepiness, or low energy
Poor feeding: Trouble feeding well or tiring quickly during feeds
Answer nugget: PA-VSD symptoms typically include blue or gray skin, fast breathing or shortness of breath, tiredness, and not feeding well — and the skin color change may be harder or easier to see depending on the baby's skin color [1].
When to Seek Care
PA-VSD typically is found during pregnancy or soon after birth. If your baby has symptoms of this condition after birth, call a healthcare professional right away [1]. Because PA-VSD is life-threatening, any newborn showing blue or gray skin coloration or breathing difficulty should be evaluated immediately.
Figure 2: The four signs of PA-VSD in newborns. Any of these signs, especially blue or gray skin or breathing difficulty, requires an immediate call to a healthcare professional.
What Causes PA-VSD?
The cause of PA-VSD is not clear [1].
What is known is when these problems begin. Most congenital heart conditions, including pulmonary atresia, happen during the first six weeks of pregnancy. That is when the major blood vessels that run to and from the heart begin to grow [1].
In PA-VSD, two structural problems exist [1]:
The pulmonary valve isn't fully formed.
There is a hole in the heart called a ventricular septal defect. The hole lets blood flow into and out of the right lower heart chamber.
How Blood Reaches the Lungs Without a Working Pulmonary Valve
Because the pulmonary valve stays closed, a baby with PA-VSD depends on other routes for blood to reach the lungs [1].
Some blood may flow through a natural opening called the ductus arteriosus. The ductus arteriosus usually closes soon after birth, but medicines can keep it open [1].
In babies with pulmonary atresia, the lung arteries — called the pulmonary arteries — can be very small or missing. If the blood vessels are missing, other vessels form on the body's main artery, the aorta. These new vessels help send blood to the lungs. They are called major aortopulmonary collateral arteries, or MAPCAs [1].
Answer nugget: When the pulmonary arteries are missing, collateral vessels called MAPCAs form on the aorta to send blood to the lungs — and their presence shapes which treatment a baby receives [1].
Risk Factors
It's not clear what raises the risk of PA-VSD specifically. However, possible risk factors for congenital heart conditions in general may include [1]:
Smoking: Smoking during pregnancy or being around cigarette smoke raises the risk of some congenital heart conditions — quitting lowers it
Alcohol use: Drinking alcohol during pregnancy may raise the risk of heart conditions in the baby
Some medicines: Certain pregnancy medicines may raise risk, including lithium for bipolar disorder and isotretinoin for acne — discuss all medicines with your healthcare team
Genetics: Changes in some genes may affect how a baby's heart forms; for example, people with Down syndrome are often born with heart conditions
Diabetes: Type 1 or type 2 diabetes during pregnancy may change how a baby's heart forms; gestational diabetes (which develops during pregnancy) typically does not raise the baby's risk
Rubella: Having rubella (German measles) during pregnancy can change heart formation; a blood test before pregnancy can show immunity, and a vaccine is available if you are not immune
How Is PA-VSD Diagnosed?
Healthcare professionals usually diagnose PA-VSD soon after birth, using tests to check the baby's heart health. Notably, it is often found during pregnancy as well, when a fetal echocardiogram can diagnose pulmonary atresia before birth [1] [2].
Pulse oximetry: A simple test — a small sensor clips onto a hand or foot — checks the amount of oxygen in the blood
Chest X-ray: Standard imaging that shows the shape and size of the heart and lungs
Echocardiogram: An ultrasound of the heart — sound waves make images of the beating heart; done before birth it is called a fetal echocardiogram — can diagnose pulmonary atresia, even before birth
ECG (electrocardiogram): A quick test — electrodes stick to the chest and sometimes arms or legs, with wires connected to a computer — finds irregular heartbeats
Cardiac catheterization: A thin, flexible tube (catheter) is placed in a blood vessel, usually in the groin or wrist, and guided to the heart; contrast dye flows through the catheter and helps the heart arteries show up clearly on images
Cardiac CT scan: Several X-rays make pictures of the heart and blood vessels, showing the shape of the heart and lungs and helping diagnose MAPCAs, which is important for planning treatment
Answer nugget: A fetal echocardiogram — an ultrasound of the heart done before birth — can diagnose pulmonary atresia while the baby is still in the womb [2].
Treatment: Four Pathways to Restore Blood Flow
A baby with PA-VSD needs treatment right away. Treatment may include one or more surgeries or procedures, all aimed at improving blood flow to the lungs and helping the heart work better. The plan depends on the structure of the pulmonary arteries and whether MAPCAs are present [2].
Figure 3: The four treatment pathways for PA-VSD. The plan depends on the baby's pulmonary artery structure and whether MAPCAs are present.
1. Catheter Procedure (Sometimes with a Stent)
A doctor threads thin, flexible tubes called catheters into the baby's blood vessels to look at the heart and lung blood flow. Sometimes a rigid tube called a stent is placed in the patent ductus arteriosus. This keeps the vessel open and lets blood flow into the lungs [2].
2. Systemic-to-Pulmonary Artery Shunt
This surgery creates a new path — a bypass or shunt — from the main blood vessel leading out of the heart (the aorta) to the pulmonary arteries. It lets enough blood flow to the lungs. Babies may need this in the first few days of life. An example is the Blalock-Taussig shunt, also called the BT shunt. Most babies outgrow this shunt within a few months [2].
Answer nugget: The BT shunt (Blalock-Taussig shunt) creates a bypass from the aorta to the pulmonary arteries and may be needed in the first days of life — most babies outgrow it within a few months [2].
3. Complete Repair
A surgeon may do a complete repair when a baby is young, or after placing a shunt or stent. During complete repair, the surgeon closes the hole in the heart and creates a pathway between the right lower heart chamber and the pulmonary artery [2].
4. Unifocalization
Sometimes, when most of the blood going to the lungs flows through MAPCAs, those blood vessels need to be connected. This surgery is called unifocalization. It may be done in stages, may be performed as part of a complete repair, or may be the first step toward an eventual complete repair [2].
Catheter procedure ± stent: Assess blood flow and keep the ductus arteriosus open — a stent in the ductus arteriosus lets blood reach the lungs
Systemic-to-pulmonary artery shunt (e.g., BT shunt): Creates a bypass from the aorta to the pulmonary arteries — may be needed in the first days of life; most babies outgrow it within months
Complete repair: Fixes the heart's structure — the heart hole is closed and a pathway to the pulmonary artery is created
Unifocalization: Connects the MAPCA vessels — done in stages when most lung blood flow is through MAPCAs, as a step toward complete repair
Lifelong Follow-Up
Babies with PA-VSD need regular checkups by a doctor trained in heart conditions present at birth. This type of doctor is called a congenital cardiologist [2].
Because PA-VSD requires multiple stages of care — sometimes stent, then shunt, then repair — coordination with a pediatric heart team and consistent follow-up through childhood and beyond is essential.
Conclusion and Next Steps
PA-VSD is a serious congenital heart defect, but it is treatable. The condition combines a closed pulmonary valve and a hole between the heart's pumping chambers, cutting off normal blood flow to the lungs. Yet modern treatment offers a clear path forward: a stent to keep the ductus arteriosus open, a shunt to route blood to the lungs in the first days of life, staged unifocalization when MAPCAs are involved, and a complete repair that closes the hole and creates a lasting pathway to the pulmonary artery.
Your next step: if PA-VSD is suspected or diagnosed in your baby, act on the treatment plan immediately — this condition needs attention right away. Connect with a pediatric heart team, ask which of the four treatment pathways fits your baby's anatomy, and plan on regular lifelong checkups with a congenital cardiologist. If you are pregnant and a fetal echocardiogram has raised concerns, use this guide to prepare your questions before delivery so your care team is ready from the first hours of your baby's life.
Frequently Asked Questions
1. What is pulmonary atresia with ventricular septal defect?
PA-VSD is a congenital heart defect a baby is born with. The pulmonary valve — the valve between the heart and the lungs — isn't fully formed and stays closed, so blood cannot flow from the right ventricle to the lungs. A hole (the ventricular septal defect) also connects the two pumping chambers of the heart [1].
2. Is PA-VSD life-threatening?
Yes. PA-VSD is life-threatening because a baby with it eventually doesn't get enough oxygen. Treatment — one or more procedures or surgeries to fix the heart — is needed right away [1].
3. What are the signs of PA-VSD in a newborn?
Symptoms may appear soon after birth and include blue or gray skin (which may be harder or easier to see depending on skin color), fast breathing or shortness of breath, tiredness, and not feeding well [1].
4. What causes PA-VSD?
The cause of PA-VSD is not clear. Most congenital heart conditions, including pulmonary atresia, happen during the first six weeks of pregnancy, when the major blood vessels to and from the heart begin to grow [1].
5. What are MAPCAs, and why do they matter?
Major aortopulmonary collateral arteries (MAPCAs) are vessels that form on the aorta when the pulmonary arteries are very small or missing. They help send blood to the lungs. Their presence shapes the treatment plan — babies with significant MAPCAs may need a staged surgery called unifocalization [1] [2].
6. Can PA-VSD be diagnosed before birth?
Yes. An ultrasound of the heart done before birth — a fetal echocardiogram — can diagnose pulmonary atresia. Most cases are found during pregnancy or soon after birth [2].
7. What treatments are available for PA-VSD?
Treatment may include a catheter procedure with a stent placed in the ductus arteriosus, a systemic-to-pulmonary artery shunt (such as the BT shunt), complete repair of the heart, and unifocalization to connect MAPCA vessels. Babies may need one or more of these, depending on their pulmonary artery structure [2].
8. Who takes care of a child with PA-VSD long-term?
Babies with PA-VSD need regular checkups with a congenital cardiologist — a doctor trained in heart conditions present at birth [2].
References
External resources: American Heart Association — Congenital Heart Defects · National Heart, Lung, and Blood Institute — Congenital Heart Defects · CDC — Facts About Pulmonary Atresia · Mended Little Hearts
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Content is based on the cited clinical sources and is current as of August 18, 2026. PA-VSD is a life-threatening condition — always follow the guidance of your baby's healthcare team immediately.
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