Tetralogy of Fallot

Also known as: tetralogy, TOF

What is Tetralogy of Fallot (TOF)?

Tetralogy of Fallot (TOF) is a heart condition of several (“tetralogy” refers to four) defects present at birth that occur due to abnormal development of the heart during pregnancy. TOF is one of the most common congenital heart defects.

  • Ventricular Septal Defect (VSD): An opening in the wall that divides the two lower chambers of the heart known as the right and left ventricles.
  • Overriding aorta: The aorta is moved to right side of the heart so that it sits over the ventricular septal defect.
  • Pulmonary obstruction: A muscular obstruction in the right ventricle that lowers normal blood flow.
  • Right ventricular hypertrophy: The right ventricle becomes thickened as it tries to pump blood past the obstruction

What are the signs/symptoms?

  • cyanosis, a blue skin color indicating a decrease in oxygen in the bloodstream
  • irritability
  • lethargy

What causes Tetralogy of Fallot?

At times, TOF may occur as part of a syndrome such as Down syndrome; however most of the time, this heart defect happens by chance.

How is Tetralogy of Fallot diagnosed?

TOF may be discovered during your child’s physical exam, while a pediatrician is listening to his/her heart. If a heart murmur (an abnormal heart sound) is detected, your child will be referred to a pediatric cardiologist for a diagnosis. Tests that a pediatric cardiologist may recommend include:

  • Chest X-ray
  • Echocardiogram (ECHO): A fetal echo is an ultrasound of your baby’s heart. A fetal echo checks your baby’s heart structure, rhythm, and function as well as the growth and development of your baby.
  • Electrocardiogram (ECG): An electrocardiogram checks for problems with the electrical activity of the heart.

Treatment for Tetralogy of Fallot

If your baby is diagnosed with TOF, the treatment is surgical repair of the defects. The repair will permit the blood to travel its usual route through the pulmonary artery to receive oxygen.


This page was last updated on: May 22, 2023 02:20 PM

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Repair of Tetralogy of Fallot in Nearly 400 patients, a Single Center Experience: 1995-2019

May 22, 2019 – The Heart Institute at Nicklaus Children’s Hospital remains dedicated to providing the very best and safest experience for patients undergoing congenital heart surgery. This report will review the program’s 24-year surgical experience in repairing children with a diagnosis of tetralogy of Fallot (TOF).