Tetralogy of Fallot

Tetralogy of Fallot is a heart condition in which a baby is born with four abnormalities in how their heart developed. These issues make it hard for the baby’s heart to send enough oxygen to their entire body.

Normally, your blood travels a specific route through your heart with every heartbeat. Because of the structural abnormalities in a heart with tetralogy of Fallot, some blood that doesn’t have oxygen in it can go into the aorta and out to the body instead of to the pulmonary artery to get oxygen.

Four abnormalities of tetralogy of Fallot

People who have tetralogy of Fallot usually have these four issues:

1. The wall that separates your left and right ventricles has a hole (ventricular septal defect) in it, which lets blood without oxygen combine with blood that has oxygen in it.
2. Your pulmonary valve and main pulmonary artery aren’t wide enough, so there isn’t enough blood getting through to your lungs with each heartbeat.
3. The aorta and its valve are shifted over. Instead of only being above the left ventricle, they’re above and open to both ventricles because the wall between the ventricles isn’t complete. This allows blood that’s supposed to go to your pulmonary artery (to get oxygen from your lungs) to go to your aorta. Instead of going to get oxygen, that blood goes out to your body.
4. The wall of muscle around your right ventricle is too thick (ventricular hypertrophy) because it’s working harder than it should to make up for the heart’s other abnormalities.

Who does tetralogy of Fallot affect?

Tetralogy of Fallot tends to happen more often in babies who are assigned male at birth (AMAB). Healthcare providers also see tetralogy of Fallot often in babies that have Down syndrome or other chromosome disorders.

How common is tetralogy of Fallot?

Tetralogy of Fallot is rare. One out of about 2,500 babies born in the U.S. each year has tetralogy of Fallot. It is, however, one of the more common congenital (since birth) heart disorders.