Tetralogy of Fallot (TOF) | Symptoms & Causes

What are the symptoms of tetralogy of Fallot?

Cyanosis, which is a blue color of the skin, is often the first sign of tetralogy of Fallot (TOF). This happens when the amount of oxygen in the blood is lower than normal. In other cases, a heart murmur is the first sign.

Even after a baby is diagnosed with TOF, there may be no symptoms for weeks or even months. Some babies will show signs of failure to thrive — becoming tired with feeding, poor weight gain — if the amount of lung blockage is mild. Typically, babies start with mild symptoms that worsen over time.

Tet spells

Tet spells, also known as hypercyanotic episodes, are a more severe symptom of TOT. These spells can occur after feeding, bathing or crying. They result from a further decrease in blood flow to the lungs, making the baby more blue.

What causes tetralogy of Fallot?

Most cases of TOF have no genetic association; however, there are some cases with a genetic link. Parents who already have a child with a congenital heart defect are more likely to have a second child with a heart defect.