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Tetralogy of Fallot (TOF)

What Is Tetralogy of Fallot?

The main function of your heart is to pump blood through the rest of your body. This blood gives your body nutrients and oxygen. If your heart doesn’t work properly, it may not be efficient in pumping blood to other organs. This affects the amount of oxygen getting to other bodily tissues. Sometimes, there are defects or problems with the heart when a person is born. These defects are known as congenital heart defects.

Tetralogy of Fallot (TOF) is a congenital heart defect that can be fatal if it’s left untreated. It’s also known as "tet." The "tetra" in the name of the condition comes from the four problems associated with it. The condition is named after Dr. Etienne Fallot.

The four heart defects associated with TOF are:

  • a hole between the right and left ventricles, which is also called a ventricular septal defect (VSD)
  • a narrow pulmonary outflow tract, which connects the heart with the lungs
  • a thickened right ventricle
  • an aorta that has a shifted orientation and lays over the VSD

The condition causes cyanosis. This means it causes the skin to have a bluish hue due to the lack of circulating oxygen. Typically, oxygenated blood gives the skin its pinkish hue.

TOF is rare, but it’s the most common cyanotic congenital heart disease.

What Are the Symptoms of Tetralogy of Fallot?

The symptoms of TOF may be present at birth or shortly afterward. They include:

  • a bluish skin color
  • clubbed fingers, or growths of skin and bone around the fingernails
  • problems with eating
  • failure to gain weight
  • developmental delays or problems
  • episodes of passing out

What Are the Causes and Risk Factors of Tetralogy of Fallot?

The exact cause of TOF is unknown, but several risk factors have been associated with the condition. These include:

  • maternal alcoholism
  • diabetes
  • maternal age that’s over 40
  • poor prenatal diet

People with TOF often have other congenital disorders such as Down syndrome.

How Is Tetralogy of Fallot Diagnosed?

Sometimes, a doctor will diagnose TOF while the baby is still in the mother’s uterus when a fetal ultrasound displays a heart abnormality. Your doctor can also diagnose it shortly after birth if they hear a murmur during a heart exam or if the baby’s skin color is bluish.

People most often receive a diagnosis in infancy, but if the defects aren’t severe, the symptoms may be minimal. This can delay diagnosis. Other times, the diagnosis comes later, such as when a parent notices something abnormal or during a regular visit to the pediatrician.

Tests that can aid in the diagnosis of TOF are:

  • a chest X-ray to check for structural abnormalities
  • an echocardiogram to check for disruptions in heartbeats
  • a heart MRI to check for structural problems
  • a pulse oximetry test to measure the oxygen level in the blood
  • a cardiac catheterization

What Is the Treatment for Tetralogy?

Treatment of TOF requires surgery. This usually occurs within the first few months of life. The surgery includes closing the VSD and enlarging the pulmonary valve. According to the Children’s Hospital of Philadelphia, if doctors can’t perform a complete repair, they’ll perform a temporary repair until a complete surgery is possible.

If TOF is left untreated, it can cause problems with heart rhythms, developmental delays, and seizures. If the condition is never fixed, which is rare, it typically causes death by the age of 20 years old. Usually, a doctor will notice the condition early on and perform surgery to correct the problem.

After having surgery for TOF, a person will need to see a cardiologist for the rest of their life. A cardiologist will perform regular follow-up exams and consult with the person’s primary care physician on any medications or health problems that are present. Some people who have surgery for TOF develop heart problems as time goes on, which makes consistent and continuous care important.

What Is the Long-Term Outlook?

Sometimes people with TOF need to limit their exercise. Talk with your doctor about whether this is necessary. If you want to be physically active, ask your doctor what would be a safe activity for you.

Take any medication your doctor prescribes as necessary. If you start to take any other medications or supplements, let your doctor know so you can avoid any adverse interactions or effects.

You can still lead a normal and productive life if you have TOF. Seeing your doctor regularly will help catch any problems before they become serious and ensure you’re staying healthy.

Content licensed from:

Written by: Jaime Herndon
Medically reviewed on: Jan 19, 2016: Debra Sullivan, PhD, MSN, RN, CNE, COI

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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