Tetralogy of Fallot (TOF) | Diagnosis & Treatment

How is tetralogy of Fallot diagnosed?

Before birth

Before a child if born, prenatal tests are performed to check for birth defects and other conditions. Tetralogy of Fallot might be seen during an ultrasound. If your doctor suspects your baby may have tetralogy of Fallot, a fetal echocardiogram (cardiac ultrasound) will be ordered to evaluate any issues with the structure of the heart and how it's functioning with this defect.

After birth

A pediatric cardiologist will listen to your baby’s heart and lungs, feel the baby’s pulses, measure the oxygen level in the blood (non-invasively) and use several tests to determine the diagnosis, including:

How is tetralogy of Fallot treated?

Essentially all children with tetralogy of Fallot (TOF) will need surgery. Many children can be managed medically until their complete repair. More severe forms may require early intervention, including hospitalization. 

Cardiac catheterization

Most babies with TOF do not need heart catheterization, but sometimes this procedure helps clarify the diagnosis. In severe circumstances, some children benefit from placing a stent in the blocked connection to the lung artery.


Children with TOF typically undergo surgery between three and six months of age. For most, a full repair surgery is performed as the initial operation. Rarely, children require a staged approach with the initial operation being a Blalock-Taussig (BT) shunt. A BT shunt is a tube placed between the body artery and the lung artery to increase blood flow to the lungs.

Full surgical repair of TOF consists of:

  • closing the ventricular septal defect (VSD) between the right and left ventricles.
  • relieving the narrowing between the right ventricle and pulmonary artery

If the child also has pulmonary atresia the surgery also will connect the right pump to the lung artery with a new valve. If your child has major aortopulmonary collateral arteries (MAPCAs), multiple procedures may be required.

What are the long-term effects of tetralogy of Fallot?

Children with TOF may need additional operation(s) or catheterization(s) as they grow older. Although the goal of the initial operation is to repair the defect, some children develop leakage from the lung valve, requiring replacement in the future. This usually occurs in adolescence or early adulthood, although it can occur sooner.

Teenagers with congenital heart defects will have to deal with medical appointments and procedures and possible restrictions on physical activities.

Adults who were treated for congenital heart disease as a child will need to be followed by a cardiologist because complications from early heart disease can arise in adulthood. ToF patients may be at some risk for arrhythmias, leaky valves and other heart problems.

Non-cardiac surgeries may pose risks for some patients and will require evaluation and discussion with a cardiologist. For female patients, pregnancy may also present risks.