Tetralogy of Fallot

Tetralogy of Fallot is a heart condition you’re born with that makes it hard to get enough oxygen to your body because of four abnormalities in your heart’s structure. Surgery in infancy repairs the issues and helps blood flow better, but you’ll need lifelong follow-ups with a provider. Even after surgery, you may need to limit sports activities.


Illustration showing four heart defects that cause tetralogy of Fallot.
The four flaws of tetralogy of Fallot.

What is tetralogy of Fallot?

Tetralogy of Fallot is a heart condition in which a baby is born with four abnormalities in how their heart developed. These issues make it hard for the baby’s heart to send enough oxygen to their entire body.

Normally, your blood travels a specific route through your heart with every heartbeat. Because of the structural abnormalities in a heart with tetralogy of Fallot, some blood that doesn’t have oxygen in it can go into the aorta and out to the body instead of to the pulmonary artery to get oxygen.

Four abnormalities of tetralogy of Fallot

People who have tetralogy of Fallot usually have these four issues:

  1. The wall that separates your left and right ventricles has a hole (ventricular septal defect) in it, which lets blood without oxygen combine with blood that has oxygen in it.
  2. Your pulmonary valve and main pulmonary artery aren’t wide enough, so there isn’t enough blood getting through to your lungs with each heartbeat.
  3. The aorta and its valve are shifted over. Instead of only being above the left ventricle, they’re above and open to both ventricles because the wall between the ventricles isn’t complete. This allows blood that’s supposed to go to your pulmonary artery (to get oxygen from your lungs) to go to your aorta. Instead of going to get oxygen, that blood goes out to your body.
  4. The wall of muscle around your right ventricle is too thick (ventricular hypertrophy) because it’s working harder than it should to make up for the heart’s other abnormalities.

Who does tetralogy of Fallot affect?

Tetralogy of Fallot tends to happen more often in babies who are assigned male at birth (AMAB). Healthcare providers also see tetralogy of Fallot often in babies that have Down syndrome or other chromosome disorders.

How common is tetralogy of Fallot?

Tetralogy of Fallot is rare. One out of about 2,500 babies born in the U.S. each year has tetralogy of Fallot. It is, however, one of the more common congenital (since birth) heart disorders.


Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Symptoms and Causes

What are the symptoms of tetralogy of Fallot?

Tetralogy of Fallot symptoms can be mild, moderate or severe. They usually get worse over time without treatment.

Tet spells

Babies who haven’t gotten treatment for tetralogy of Fallot can get “tet spells” when their oxygen level drops without warning while or after feeding, crying or pooping. Tet spells can be as short as a few minutes to as long as several hours. Your baby may sleep a lot after a tet spell.

Signs of a tet spell include:

  • Having very blue skin (cyanosis).
  • Having a limp body.
  • Feeling very tired.
  • Being restless.
  • Not responding to a parent.
  • Losing consciousness.
  • Having a hard time breathing (a squatting position can help with this).
  • Having convulsions.
  • Being unable to move one side of their body for a short time.

Other tetralogy of Fallot symptoms and signs

Tetralogy of Fallot symptoms in adults

  • Skin with a bluish tint.
  • Inability to exercise because of a lack of oxygen.
  • Fainting.
  • Chest pain.
  • Heart palpitations.

Tetralogy of Fallot complications

Other health issues can happen with tetralogy of Fallot, such as:


What causes tetralogy of Fallot?

Healthcare providers don’t know what causes tetralogy of Fallot.

Possible causes include:

  • Something in your child’s DNA may have changed, and that change rarely comes from a parent. A parent who’s had a heart abnormality since birth doesn’t normally pass it to their child. However, the risk may be higher if both parents have the heart issue.
  • Having rubella or diabetes, drinking alcohol or eating a poor diet while pregnant can put the fetus at a higher risk of a congenital heart problem.
  • Being pregnant after age 40 may be a risk factor.
  • A rare condition called phenylketonuria (a buildup of an amino acid) can increase your child’s risk of a heart issue.

Diagnosis and Tests

How is tetralogy of Fallot diagnosed?

Your healthcare provider can diagnose tetralogy of Fallot during pregnancy or after your baby is born. They usually find it in the first few weeks or months of life.

Tests before birth

During prenatal tests, your healthcare provider may see something in an ultrasound image that looks like it could be tetralogy of Fallot. From 18 to 22 weeks into your pregnancy, your provider will be able to use a fetal echocardiogram or ultrasound image of the fetus’s heart to see if the heart’s structure is normal.

Tests in infancy

If your baby has tetralogy of Fallot, your provider will most likely hear a heart murmur when listening to your baby’s heart. They can easily check your newborn baby’s oxygen level with pulse oximetry (pulse ox). If it shows a low oxygen level, your provider can do an echocardiogram (ultrasound of the heart). These tests are painless and don’t go through the surface of your baby’s skin.

  • Pulse oximetry: Before you take your baby home, your provider will put sensors on your newborn’s feet or hands to find out how much oxygen is in their blood.
  • Echocardiogram: uses sound waves to show your baby’s heart structure and how well their heart is working.
  • Chest X-ray or CT (computed tomography): This may show a heart that has the abnormal shape of a boot.

Tests in childhood or adulthood

To diagnose tetralogy of Fallot in a child or adult, a provider may use the above methods, as well as an electrocardiogram (EKG) and cardiac catheterization.


Management and Treatment

How do I manage my baby’s symptoms?

Until your baby has surgery, you can help them through tet spells. When your baby has trouble breathing, put them into a squatting position (pushing their knees to their chest). Your provider can help with extra oxygen and beta-blocker medicine to improve blood flow.

Other things you can do to help your child include making sure they:

  • Are drinking enough fluids.
  • Aren’t exercising too hard.
  • Are taking prescribed medicines.

How is tetralogy of Fallot treated?

Without tetralogy of Fallot surgery, symptoms usually get worse. Soon after birth, your baby can have surgery that will make blood move through their heart the way it should. A surgeon can make the pulmonary valve and the path to the pulmonary artery bigger. And they can patch the hole between the two ventricles so the blood without oxygen doesn’t mix with the blood that has oxygen in it.

If your baby is too small or weak for the surgery, their provider can do a simpler procedure until they can do the complete repair. Your provider can put a shunt or tube between one of the aorta’s large arteries and the pulmonary artery to help blood get to the lungs or do a catheter procedure.

These techniques can relieve symptoms for a number of years — well into adulthood — until a provider can do a more complete repair surgery.

Complications of the treatment

Often, after the complete tetralogy of Fallot surgery, the pulmonary valve leaks. If this happens, your child may need to limit their physical activity. Sometimes, a provider will need to replace the pulmonary valve. If your child’s pulmonary valve is fine, they may be able to do normal activities. Your child may also have a higher risk of abnormal heart rhythms after surgery.

How is tetralogy of Fallot surgically repaired in an adult?

To perform a complete repair, a surgeon who specializes in adult congenital heart disease closes the ventricular septal defect with a patch. They open the passageway out of the right ventricle, and repair or replace the pulmonary valve. They enlarge the pulmonary arteries to both lungs. Sometimes, they place a tube between the right ventricle and the pulmonary artery to improve blood flow.

Are there tetralogy of Fallot complications in adults who have the surgery?

Although the surgical treatment of tetralogy of Fallot is very effective in correcting the structural defects and blood flow through the heart, it can cause some ongoing abnormalities in your heart’s function. If these issues develop, additional surgery can treat them.

Many adults who undergo repair for tetralogy of Fallot don’t need further surgical treatment. One study found that 10% to 15% of people needed a reoperation over 20 years.

The potential tetralogy of Fallot complications in adults who have the surgical repair include:

  • Electrical disturbances: Having a patch on the ventricular septal defect can block your atria from sending electrical signals to your ventricles. A pacemaker can correct this.
  • Rhythm disturbances (arrhythmias): Atrial fibrillation or atrial arrhythmias in general are common complications after heart surgery. You can treat them with medication or a nonsurgical procedure. A rarer but more serious arrhythmia is ventricular tachycardia.
  • Leaking valves: The most common valve problem after a tetralogy of Fallot repair is a leaking pulmonary valve, but your aortic and tricuspid heart valves can also leak. Heart valves are designed to allow blood to flow in one direction. When a valve leaks, blood can flow backward. A surgeon or structural cardiologist can repair a leaky valve.
  • Residual ventricular septal defect: Sometimes the ventricular septal defect doesn’t seal completely and there’s some leaking around the patch. A surgeon can repair the leak if it’s large or causes major symptoms.
  • Aneurysm: Patches that repair a ventricle can cause weak sections of the ventricle to bulge out, forming an aneurysm. There’s also an increased risk of developing aneurysms of the ascending aorta. A large aneurysm requires surgical repair.


How can I reduce my risk?

Although healthcare providers don’t know the cause of tetralogy of Fallot, you may be able to reduce a fetus’s risk of tetralogy of Fallot in these ways:

  • Don’t use tobacco products or drink alcohol while pregnant.
  • Avoid certain medicines. Ask your provider for substitute medicines you can take during pregnancy.
  • If you have phenylketonuria, eat less protein.
  • Make sure your rubella vaccine is still working to keep you from getting rubella during pregnancy.
  • Keep your diabetes well managed.

Outlook / Prognosis

What can I expect if I have tetralogy of Fallot?

Although surgery for tetralogy of Fallot creates a normal blood flow path, you can still have other issues, including:

  • You can have a higher risk of an infection in your heart (endocarditis), so dental care is important. Antibiotics can help prevent infection during dental visits.
  • Babies with tetralogy of Fallot may be slower to develop and grow. They may need physical, speech or occupational therapy to help them.
  • You may have a higher risk of an abnormal heart rhythm (arrhythmia.)
  • Your provider may need to check your heart before you get pregnant, and there’s a higher risk of miscarriage. You also may only be able to use certain kinds of medicines and birth control with your heart issue as an adult.

Outlook for tetralogy of Fallot

With medical advances, the outlook for babies with tetralogy of Fallot is better than it was in the past. Most babies who have surgery today to fix tetralogy of Fallot will have active lives. They’ll need to have regular check-ups with a cardiologist, a provider who specializes in the heart.

Some adults who had tetralogy of Fallot surgery as infants may develop issues that require medicines, medical care or surgery in adulthood, such as surgery to replace their pulmonary valve. Adults should also consult with their cardiologist before having surgery on a different part of their body.

What is the life expectancy of someone with tetralogy of Fallot?

Without a repair, 30% of people with tetralogy of Fallot live to age 10 and 5% live to age 40. For those who undergo repair, 30-year survival rates range from 68.5% to 90.5%.

How old is the oldest person with tetralogy of Fallot?

Researchers have written about an 87-year-old woman who refused to have surgery for tetralogy of Fallot. This is very rare. However, many people who get a surgical repair live into their 60s, 70s and 80s.

How successful is the surgery in adults living with tetralogy of Fallot?

With an experienced congenital heart disease surgeon, surgical repair of the defect in adults has a very high success rate. In one long-term study, the 36-year survival rate for adults who underwent surgical repair for tetralogy of Fallot was 86%.

Living With

What type of ongoing care is necessary for an adult who has had surgical repair of tetralogy of Fallot?

Adults who have had initial surgery for tetralogy of Fallot as a child should have thorough cardiac evaluations every year or two. You may need various tests to check cardiac function, such as:

The shunts providers use for an initial repair can cause issues such as:

  • Narrowing (stenosis).
  • High blood pressure in the pulmonary artery.
  • Excess volume load on the left side of the heart.

An adult should have a complete repair surgery if they have any of these issues or worsening symptoms, such as cyanosis (blue skin from a lack of oxygen) or fatigue.

A complete repair often results in significant leaking of the pulmonary valve. Also, your provider will need to monitor the size and function of the right side of your heart.

People with repaired tetralogy of Fallot typically have some restrictions on certain strenuous activities, such as competitive sports.

When should I seek care?

After tetralogy of Fallot surgery, your child will need regular follow-up appointments with a provider who specializes in children’s hearts. This care will continue into adulthood.

When should I go to the ER?

If your baby is having a severe tet spell, take them to the closest emergency room. If you’ve passed out, are dizzy, are short of breath or have chest pain, you should also go to the emergency room.

What questions should I ask my doctor?

Questions to ask your provider include:

  • Will my child need to limit their sports activities after surgery?
  • Will my child need additional surgeries?
  • What medicines, if any, will my child need to take?

Additional Common Questions

Can an adult have tetralogy of Fallot?

Occasionally, a person reaches adulthood without having had any surgical repair, although this isn’t common. Specialists recommend they have a complete surgical repair to prevent future complications or sudden death.

Is pregnancy safe for people who have had tetralogy of Fallot repaired?

With proper prenatal care and careful monitoring, most people with repaired tetralogy of Fallot can carry a pregnancy safely to term.

People who have undergone surgical repair for tetralogy of Fallot and are considering pregnancy should consult an adult congenital heart disease specialist. They also should speak with an obstetrician who cares for people with special medical conditions.

A note from Cleveland Clinic

Although surgery can fix the physical abnormalities of tetralogy of Fallot, your child will need regular follow-up appointments throughout childhood and adulthood. Don’t be afraid to talk to a therapist if you feel stressed about caring for a child with tetralogy of Fallot or if you’re feeling bad about your own surgical scars. A counselor can also help kids and teens who may feel like their classmates are ahead of them in development.

Medically Reviewed

Last reviewed on 11/18/2022.

Learn more about our editorial process.

Appointments 800.659.7822