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Tetralogy of Fallot

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The Manual's Editorial Staff

Last full review/revision Jun 2020| Content last modified Jun 2020
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The heart has 4 chambers. The atria are the 2 upper chambers in your heart—the right atrium and the left atrium. The ventricles are the 2 lower chambers in your heart—the right ventricle and the left ventricle. Heart chambers work together to pump blood through the body.

  • The 2 right chambers pump blood returning from your body to your lungs

  • The 2 left chambers pump blood returning from your lungs to your body

Blood goes to your lungs to pick up oxygen and get rid of carbon dioxide.

The aorta is the main artery that carries blood with oxygen away from the left side of the heart to the body.

What is tetralogy of Fallot?

A tetralogy (tetra means four) is a group of 4 related things. Tetralogy of Fallot is a set of 4 specific heart problems that happen together. One of the doctors who identified all 4 heart problems together was named Fallot.

Babies with tetralogy of Fallot are born with these 4 heart defects:

  • The path that blood takes out of the right side of the heart to the lungs is unusually narrow

  • There is a hole in the wall between the lower chambers of the heart (ventricular septal defect)

  • The aorta is out of place

  • The side of one of the heart chambers is thicker than normal

A displaced aorta receives blood from both the right and left ventricle, instead of just the left, which allows blood not carrying oxygen to flow out to the body. The body needs oxygen in the blood, so it doesn't get enough if the aorta is displaced.

Tetralogy of Fallot: Four Defects

Tetralogy of Fallot: Four Defects

What causes tetralogy of Fallot?

Babies are born with tetralogy of Fallot. Doctors aren't sure what causes it.

What are the symptoms of tetralogy of Fallot?

The main symptom of tetralogy of Fallot is:

  • Blue skin (cyanosis) because the baby doesn't have enough oxygen in the blood

Some children have life-threatening attacks in which their oxygen level suddenly gets very low. These attacks are called tet spells or hypercyanotic spells These spells may be triggered by crying, pooping, playing, or things that make the heart beat faster. They are most common around 2 to 4 months of age but can happen in toddlers.

Symptoms of these spells include:

  • Severe shortness of breath

  • Limpness

  • Loss of consciousness

Sometimes, children die during a spell.

How can doctors tell if my child has tetralogy of Fallot?

Doctors suspect tetralogy of Fallot if they hear a certain type of heart murmur (an unusual sound made by abnormal blood flow). Doctors confirm the diagnosis by:

  • Echocardiography (ultrasound of the heart)

  • Sometimes, CT scan or MRI

  • ECG (a painless test that measures the heart’s electrical currents and records them on a piece of paper)

  • Chest x-rays

How do doctors treat tetralogy of Fallot?

Doctor will:

  • Do surgery to repair the heart defects, usually between 2 and 6 months of age

  • Sometimes give a certain medicine (prostaglandin) to help blood flow

For some babies, doctors need to do several procedures to repair the heart.

If your baby has tet spells, doctors will:

  • Have you pull your baby's knees close to their chest to help with blood flow (older children may squat down, which also helps)

  • Have you try to calm the baby

  • Give oxygen

  • Give medicine and fluid by vein (IV)

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