Total anomalous pulmonary venous connection (TAPVC) is a congenital heart defect in which the pulmonary veins that connect the lungs to the heart are attached in the wrong place. Around 400 babies are born with TAPVC in the United States every year, making it a rare disease.
In patients with TAPVC, the oxygen-rich blood from the lungs doesn’t return to the right part of the heart. Instead of flowing into the upper left chamber of the heart, the blood ends up in the upper right heart chamber. This causes the oxygen-rich blood from the lungs to go to a chamber that contains oxygen-poor blood.
There are three different types of TAPVC, depending on where the pulmonary veins are connected to the heart. These include:
- Supracardiac TAPVC, in which the pulmonary veins are connected above the heart to another blood vessel – the superior vena cava – which is the blood vessel that brings oxygen-poor blood back to upper-right chamber of the heart from the body.
- Cardiac TAPVC, in which pulmonary veins connect to the right side of the heart. Another vein, called the coronary sinus (which brings oxygen-poor blood from the heart muscle back to the heart) helps connect these pulmonary veins to the upper right heart chamber.
- Infracardiac TAPVC, in which the pulmonary veins are abnormally connected below the heart.
What is the cause and risk factors of TAPVC?
The causes of congenital heart defects remain largely unknown, but genetic factors are believed to play a role. Environmental risk factors, such as things the fetus is exposed to during pregnancy, may also contribute to the development of TAPVC.
What are the possible symptoms of TAPVC?
Symptoms that alert medical professionals to the presence of a problem will usually develop right around the time of birth or soon after. In some children without obstruction to pulmonary venous return, symptoms may take a long time to present. The symptoms, which are often more severe in children with worse obstruction, include:
- Cyanosis, in which the baby takes on a bluish skin tone due to a severe lack of oxygen.
- Breathing difficulties, including a fast respiratory rate or grunting noises.
- A pounding heart.
- A weak pulse.
- Extreme sleepiness.
- A heart murmur, an abnormal sound that is emitted by the heart due to turbulent blood flow.
What types of activities can children with TAPVC engage in?
If your child has TAPVC, they will likely be advised to limit the amount of physical activity they participate in, as overexertion is dangerous. You should consult with your child’s doctor before letting them participate in more strenuous sports, as they can help gauge the safe level of physical activity for your child.
How is TAPVC diagnosed?
While TAPVC can be diagnosed when the mother is still pregnant, it is more often diagnosed as soon as the baby is born. When the mother is pregnant, doctors can administer screening tests that can help check for birth defects. Findings from an ultrasound scan can tip the doctor off that the patient may have a heart defect, causing them to request a fetal echocardiogram to explore the situation and confirm the diagnosis.
In order to diagnose Total Anomalous Pulmonary Venous Connection after a child has been born, a doctor will check the child’s signs and symptoms, conduct a physical exam, and listen to the baby’s heart for a heart murmur (an abnormal whooshing sound due to turbulent flow).
While there are several different tests that can be used to diagnose the disease, doctors often use echocardiogram, which is a technique that uses ultrasound waves to make a moving image of the heart. This test can also be used to check for blood flow. Additional tests that may be recommended include:
- Cardiac catheterization, which can check if the pulmonary veins have an obstruction.
- Electrocardiogram, to see if the right atrium and ventricle are enlarged, how big the atrial septal defect is, and how much blood is flowing through it.
- Chest x-rays, which will show an enlargement of the right side of the heart.
- Pulse oximetry, to determine blood oxygen levels.
How is TAPVC treated?
TAPVC is usually treated with surgery when the child is very young, generally during infancy. In order to fix the defect, the surgeon will connect the pulmonary veins to the left side of the heart and close the hole between the two upper chambers. After the surgery, children with this disease will need to be closely monitored by doctors for the rest of their life. Adults who have this defect will need care for the duration of their life and require follow-up appointments to check for changes in their condition.