Tetralogy of Fallot (ToF) is a combination of four heart defects that are present at birth (congenital). ToF develops in an unborn baby early in pregnancy, while the heart is developing. When you have ToF, some blood does not reach the lungs for oxygen, and blood that enters the heart mixes with blood that is leaving the heart. This makes it difficult for the body to get enough oxygen-rich blood.

• A hole in the heart (ventricular septal defect, or VSD).
• A missing or underdeveloped valve that limits blood flow from the right side of the heart to the lungs (pulmonary stenosis).
• Thickening of the muscles on the right side of the heart (right ventricle hypertrophy).
• Abnormal position of the main blood vessel that carries blood away from the heart (overriding aorta).

You may have some symptoms of ToF as an adult, even if you had surgery to correct the defect when you were younger. Symptoms during adulthood depend on the type of defect that you have and how successful your prior surgery was. The most common problem for adults with ToF is a leaky valve between the heart and lungs. Problems in other areas of the heart or lungs can also develop.

What are the causes?

The cause of this condition is not known. In some cases, it may be caused by genes that are passed from parent to child (inherited).

What are the signs or symptoms?

• Low energy or tiredness.
• Inability to exercise.
• Abnormal heart rate (too fast or too slow).
• Abnormal heart rhythm.
• A feeling that the heart is fluttering.
• Dizziness or fainting.
• Cough.
• Shortness of breath.

How is this diagnosed?

• A physical exam.
• Blood tests.
• Electrocardiogram (ECG) to check for irregular heartbeats (arrhythmias). This test may be done while you exercise (stress test).
• Echocardiogram to check for heart changes.
• Chest X-ray.
• Heart MRI.
• A Holter monitor or event monitor test. This test involves wearing a portable device that monitors your heart rate over time.
• A pulse oximetry test. This test checks the amount of oxygen in your blood.
• Placing a long, flexible tube (catheter) into your heart to measure pressure inside of your heart chambers (cardiac catheterization).

You may see a heart specialist (cardiologist) to manage this condition.

How is this treated?

• Medicine that:
  • Controls your blood pressure.
  • Controls your heart rate or your heart's ability to pump blood.
  • Helps the body get rid of excess fluids (diuretic).
  • Helps prevent infection of the inner layer of the heart or the heart valves (endocarditis). Antibiotics may be given before you have certain dental procedures.
  • Thins the blood (anticoagulant) to prevent blood clots in your heart.
• An electrical device that helps to regulate your heart rhythm (pacemaker or cardioverter defibrillator).
• Surgery to repair or replace a leaky heart valve.
• A heart transplant, if heart failure begins to develop. This is rare.

Follow these instructions at home:

Medicines

• Take over-the-counter and prescription medicines only as told by your health care provider. Check with your health care provider before starting any new medicines.
• Ask your health care provider whether you need to take antibiotics before you go to the dentist.

Lifestyle

• Do not use any products that contain nicotine or tobacco, such as cigarettes, e-cigarettes, and chewing tobacco. If you need help quitting, ask your health care provider.
• Do not abuse drugs or alcohol.
• If you drink alcohol:
  • Limit how much you use to:
    • 0–1 drink a day for nonpregnant women.
    • 0–2 drinks a day for men.
  • Be aware of how much alcohol is in your drink. In the U.S., one drink equals one 12 oz bottle of beer (355 mL), one 5 oz glass of wine (148 mL), or one 1½ oz glass of hard liquor (44 mL).

General instructions

• Eat a heart-healthy diet and maintain a healthy weight. A heart-healthy diet includes whole grains, fresh fruits and vegetables, low-fat dairy products, and lean proteins. Work with a dietitian, if needed.
• Exercise as told by your health care provider. You may need to limit exercise that takes a lot of effort, such as weight lifting or competitive sports. Ask your health care provider what activities are safe for you.
• Wear a medical alert bracelet or necklace. This tells anyone caring for you in an emergency that you have a heart condition.
• Keep a record of your medical information to share with your health care providers. Make sure that you know:
  • Which type of defect you were born with.
  • Which surgeries you have had.
  • Which medicines you are taking.
• If you are considering pregnancy:
  • Work with a cardiologist and a pregnancy specialist (obstetrician) who are familiar with managing heart defects during pregnancy.
  • You may decide to have a blood test to check whether you carry genes that could cause ToF in your baby.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if:

• You have symptoms of heart disease, such as:
  • Dizziness.
  • Fatigue.
  • Feeling your heart flutter.
  • A heartbeat that is too fast or too slow.
  • Trouble exercising.
  • Coughing often.
• You become pregnant or you plan to become pregnant.

Get help right away if:

• You have chest pain.
• You have trouble breathing.
• You faint.

Summary

• Symptoms of ToF during adulthood depend on the type of defect that you have and how successful your prior surgery was.
• Exercise as told by your health care provider. You may need to limit exercise that takes a lot of effort, such as weight lifting or competitive sports. Ask your health care provider what activities are safe for you.
• You may see a heart specialist (cardiologist) to manage this condition.