Tetralogy of Fallot consists of 4 defects:

  1. A hole (ventricular septal defect) between the two lower heart chambers (ventricles).
  2. There is an obstruction from the right ventricle to the lung caused by thick muscle (infundibular stenosis) and/or narrowing of the pulmonary valve (pulmonary stenosis).
  3. The aorta, which is the major artery that supplies oxygen-rich blood to the body, lies over the ventricular septal defect (overriding aorta).
  4. The muscle of the right ventricle becomes thick (right ventricular hypertrophy).

Less oxygenated ‘blue’ blood returning to the right side of the heart is mixed with the oxygenated ‘red’ blood from the left side of the heart through the hole and into the overriding aorta. Babies with unrepaired TOF are often blue. Sometimes, the pulmonary valve is also completely obstructed (pulmonary atresia).

Surgical Intervention

In early infancy, babies with TOF may need a procedure to temporarily increase blood flow to the lung (Blalock- Taussig shunt). Total surgical repair will be done later when the baby is older. In adulthood, there may be residual obstruction from the thick muscle in the right heart chambers or from narrowed pulmonary valve. Sometimes, the pulmonary valve may become leaky (does not close properly) after the   initial childhood repair. Thus, further operation (pulmonary valve replacement) may be necessary during adulthood.


You may need to restrict your activity especially if your heart function is weak or there is presence of abnormal heart rhythm. Your cardiologist will determine the limitations.

Prevention of Endocarditis

You will need antibiotic to prevent endocarditis (infection of the inner layer of the heart) before any surgical or dental procedures. Antibiotic may also be required if you should go for body piercing or tattooing.


There are some associated risks with pregnancy even after TOF repair is done. Please consult your cardiologist for advice.