Total Anomalous Pulmonary Venous Drainage – T.A.P.V.D
What is T.A.P.V.D?
T.A.P.V.D stands for Total Anomalous Pulmonary Venous Drainage. It is an incredibly rare congenital heart defect (approximately 1 in 20,000 babies are born with it.)
T.A.P.V.D is where the pulmonary veins, which bring oxygenated blood from the lungs and back to the heart, don’t connect to the left atrium as they should. Instead the pulmonary veins connect to various other veins which lead to the right atrium. This is a serious problem as the right atrium ultimately sends blood to the lungs via the pulmonary artery to become oxygenated and because the pulmonary veins, carrying oxygenated blood, are connected to the right atrium oxygenated blood is constantly being sent to the lungs. Thus oxygenated blood won’t ever reach respiring tissues!
That is why an atrial septal defect or a foramen ovale is required for survival of Total Anomalous Pulmonary Venous Drainage. An atrial septal defect is a hole between the two atria and allows oxygenated blood to mix with deoxygenated blood forming partially oxygenated blood. This then allows the new-born’s respiring tissues to receive some oxygen and hence remain alive. A foramen ovale also allows blood to move from the Right Atrium to the Left Atrium.
Variations of T.A.P.V.D
There are four types of T.A.P.V.D – which one you have depends on where the pulmonary veins are connected to.
- Supracardiac T.A.P.V.D is where the pulmonary veins are connected to the Superior Vena Cava.
- Infracardiac T.A.P.V.D (also known as Infradiaphragmatic T.A.P.V.D) is where the pulmonary veins join to the Inferior Vena Cava.
- Cardiac T.A.P.V.D is where the pulmonary veins lead blood to the right atrium through the coronary sinus.
- Mixed T.A.P.V.D is where the pulmonary veins are connected to various sites and so it is a mix between any or all of the previously mentioned forms of T.A.P.V.D
In Summary all of the types of T.A.P.V.D end up sending blood to the Right Atrium instead of the Left Atrium.
There is also a similar condition called P.A.P.V.D. The difference being that P.A.P.V.D stands for Partially Anomalous Pulmonary Venous Drainage and it is where some of the pulmonary veins connect normally to the Left Atrium and the others are positioned incorrectly leading to the Right Atrium. Furthermore, T.A.P.V.D is life threatening and is usually diagnosed within the first few days of the baby’s life whereas P.A.P.V.D can be diagnosed at any time in one’s life, even at old age, due to it being less severe.
T.A.P.V.D is usually detected a couple of days after birth because it is rather difficult to do so during pregnancy. This is because the doctor first needs to suspect a heart problem from the prenatal scans and then if the doctor suspects a problem then further tests may be carried out such as a foetal echocardiogram. However, these tests may not necessarily lead to the discovery of the serious congenital heart defect. This is because for T.A.P.V.D to be confirmed the pulmonary veins need to be seen incorrectly positioned and leading to the Right Atrium. However, not much blood goes to the lungs of a foetus therefore the doctor won’t be able to see the pulmonary veins properly because they wouldn’t show up clearly and so T.A.P.V.D wouldn’t be detected because the doctor can’t tell if the veins are connected to the correct area. Consequently, it is uncommon for T.A.P.V.D to be detected during pregnancy and it is much more likely that it would be detected soon after birth due to the various symptoms.
The signs and symptoms after birth are seen quite quickly and these include:
- Cyanosis – a blue skin colouration because of the lack of oxygen.
- Breathing difficulties
- Abnormal Heart Sounds
- Heart Murmur
- Poor feeding / weight gain / growth
At this point it is unknown what condition the baby has therefore a number of tests would be carried out such as:
- An electrocardiogram ( which measures the electrical activity of the heart)
- Chest x-rays
- Echocardiogram (ultrasound of the heart)
- MRI of the heart
- Cardiac catheterisation
These tests ultimately lead to the diagnosis of T.A.P.V.D because they would inform the doctors that the pulmonary veins are connected to the wrong chamber of the heart. It would also allow them to see if there are any other abnormalities.
The treatment is open heart surgery as soon as possible. First of all the chest has to be opened up using a saw allowing the heart to be seen. Once open the surgeon would connect the pulmonary veins to the correct place and the atrial septal defect would be closed. After that the sternum needs to be put back together and the skin would need stitching up; leaving a large scar from the top of the chest to the bottom of the sternum. The surgery is carried out under general anaesthetic and the survival rate is approximately 90%.
There are a number of complications that can arise due to the surgery including:
- Arrhythmia – an irregular heartbeat that can be too fast or too slow.
- Breathing difficulties
- Heart failure
- Lung infections
- Organ failure
- Formation of an obstruction at the new connection
After the operation the patients are placed in post-operative intensive care and they usually require a ventilator.
The outlook of a patient after successful operation and correction of T.A.P.V.D is very good. They are able to lead normal lives unless of course they developed complications.
They will however need to regularly visit a cardiologist who would keep an eye open to make sure no complications or other problems crop up e.g. the formation of an obstruction at the new connection or heartbeat abnormalities.