Total anomalous pulmonary venous return (TAPVR)

Overview

Total anomalous pulmonary venous return (TAPVR) is a rare heart condition that's present at birth. That means it's a congenital heart defect. You also may hear this called congenital heart disease.

In this heart condition, blood vessels that return blood from the lungs to the heart, called the pulmonary veins, attach to the wrong place in the heart.

In a typical heart, oxygen-rich blood flows from the lungs to the upper left heart chamber, called the left atrium. Blood then goes to the rest of the body.

In TAPVR, where the veins connect is changed. Instead of flowing through the left atrium, blood flows through the upper right heart chamber, called the right atrium. This change in blood flow causes the oxygen-rich blood from the pulmonary veins to mix with oxygen-poor blood that also flows into the right atrium. As a result, blood flowing to the body doesn't have enough oxygen.

Another name for this condition is total anomalous pulmonary venous connection (TAPVC). The names TAPVR and TAPVC refer to the same congenital heart defect. Both terms are used and widely accepted.

TAPVR is different from partial anomalous pulmonary venous return (PAPVR). In PAPVR, only some of the pulmonary veins attach to the wrong place in the heart. Some veins are not affected.

TAPVR types are classified by where the pulmonary veins connect and drain. There are four major types:

• Supracardiac: The pulmonary veins connect above the heart, usually through a vein that carries blood to the major vein, called the superior vena cava. The superior vena cava brings oxygen-poor blood to the right side of the heart.
• Infracardiac/infradiaphragmatic: The pulmonary veins connect below the heart and diaphragm, most often to a vein in the liver called the portal vein. Other connections are also possible.
• Intracardiac: The pulmonary veins connect directly to the right side of the heart, usually through a vein called the coronary sinus, or connect directly into the right atrium.
• Mixed: The pulmonary veins have more than one type of atypical connection. For example, three veins may drain together while the fourth drains through a different pathway.

Supracardiac TAPVR is the most common type. Between 40% and 50% of people with TAPVR have the supracardiac type.

There also are differences between obstructed and unobstructed TAPVR.

In obstructed TAPVR, the atypical pathway is narrowed or blocked. This makes it difficult for blood to leave the lungs, causing pressure and fluid to build up in the lungs. Newborns and infants with obstructed TAPVR can become very sick soon after birth.

In unobstructed TAPVR, there is no major narrowing or blockage in the atypical pathway. Blood can flow more easily, but it still returns to the wrong side of the heart. This causes too much blood to flow through the lungs and makes the right side of the heart work harder. Symptoms may be mild at first, but babies can develop serious symptoms over time.

Symptoms

Symptoms of total anomalous pulmonary venous return (TAPVR) in newborns and infants may include:

• Trouble breathing.
• Poor feeding.
• Weak pulse.
• A change in skin color due to low oxygen levels. This is called cyanosis. The skin may appear gray or blue. Depending on skin color, these changes may be easier or harder to see.

Symptoms of TAPVR may appear soon after birth. But some people don't have symptoms until later in life. Newborns and infants with obstructed TAPVR often become very sick soon after birth. Babies with unobstructed TAPVR may have milder symptoms at first. Serious symptoms may develop over time.

Serious congenital heart defects are often diagnosed before or soon after a child is born. If you think that your newborn or infant has symptoms of total anomalous pulmonary venous return (TAPVR), call your child's healthcare professional.

Causes

The exact cause of most congenital heart defects, including total anomalous pulmonary venous return (TAPVR), is not known. Most congenital heart defects result from changes that happen early as the baby's heart develops before birth.

Changes in the genes, some medicines or health conditions, and environmental or lifestyle factors, such as smoking, may play a role.

Risk factors

There are no known risk factors specifically for TAPVR. Possible risk factors for congenital heart defects in general may include:

• Rubella, also called German measles. Having rubella during pregnancy can change how the baby's heart develops. A blood test can be done before pregnancy to see if you're immune to rubella. If you're not, you can get a vaccine.
• Diabetes. Having type 1 or type 2 diabetes during pregnancy may change how the baby's heart grows during pregnancy. Diabetes that develops during pregnancy is called gestational diabetes. Gestational diabetes generally doesn't raise the risk of congenital heart disease.
• Genetics. Although TAPVR doesn't usually run in families, changes in genes have been linked to heart conditions at birth. For example, people with Down syndrome are often born with heart conditions.
• Smoking. If you smoke, quit. Smoking during pregnancy or exposure to secondhand smoke raises the risk of congenital heart defects in the baby.
• Alcohol use. Drinking alcohol during pregnancy has been linked to heart conditions in the baby.
• Some medicines. Some medicines taken during pregnancy may raise the risk of congenital heart defects. These medicines include lithium (Lithobid) for bipolar disorder and isotretinoin (Claravis, Myorisan, others), which is used to treat acne. Talk to your healthcare team about the medicines you take.

Diagnosis

A heart ultrasound, called an echocardiogram, is needed to diagnose total anomalous pulmonary venous return (TAPVR). A healthcare professional also listens to the heart and lungs. A whooshing sound, called a heart murmur, may be heard.

Different tests that may be used to help diagnose TAPVR include:

• Chest X-rays.
• Echocardiogram. This also is called a heart ultrasound or heart sonogram.

A chest X-ray can show changes in the heart and lungs. A chest X-ray may look different depending on whether blood flow from the lungs is blocked. In obstructed TAPVR, the X-ray may show fluid buildup in the lungs. In unobstructed TAPVR, the heart may appear enlarged, and the blood vessels in the lungs may look more prominent.

In supracardiac TAPVR, an X-ray may sometimes show a rounded shadow above the heart. This is caused by the enlarged heart and the blood vessels above it that are not typical. This is sometimes called the snowman sign because the outline can look like a snowman.

An echocardiogram is the test used to diagnose total anomalous pulmonary venous return. It uses sound waves to create images of the heart as it beats. An echocardiogram can show the pulmonary veins, any holes in the heart and the size of the heart chambers. It also shows blood flow through the heart and heart valves.

Other tests such as an electrocardiogram or a CT scan may be done if more information is needed.

Diagnosis of TAPVR before a baby is born can be challenging. Prenatal ultrasound may suggest certain heart conditions. Sometimes, if TAPVR is suspected, a fetal echocardiogram may be done to help confirm the diagnosis. But TAPVR is not commonly detected during pregnancy. It is hard to see the pulmonary veins on prenatal screening tests because not much blood flows to the lungs before a baby is born.

Treatment

Total anomalous pulmonary venous return (TAPVR) is treated with surgery. The surgery usually is done when a child is a baby. The timing of surgery depends on whether there's a blockage. If there is a blockage, surgery may need to be done very soon after birth.

To repair the heart, surgeons create a connection that allows the pulmonary veins to drain into the left atrium. Surgeons also may close the atypical pathway and close the hole between the upper heart chambers when needed.

One surgical technique that may be used is repair without sutures. Sutureless repair avoids placing stitches directly in the pulmonary veins. Instead, the surgeon attaches the left atrium to the tissue surrounding the pulmonary veins. This approach may cause less injury and scarring in the veins and help lower the risk that they will become narrowed after surgery.

Most infants do well after surgery. Monitoring is important right after surgical repair to make sure the heart and lungs are working well.

Most people have good long-term outcomes after treatment for TAPVR.

A person with TAPVR needs regular health checkups for life to check for blockages or irregular heartbeats. A doctor trained in congenital heart disease should provide care. This type of healthcare professional is called a congenital cardiologist.

Coping and support

Caring for a child with TAPVR can involve ongoing medical appointments and monitoring, even after surgery. Staying connected with your child's cardiology team can help you understand follow-up care, safe activities and any symptoms to watch for.

As children with congenital heart disease grow, paying attention to their emotional and behavioral health can be an important part of their overall care.

It's also important for caregivers to look after their own well-being and seek support when needed.