There are four major defects in tetralogy of Fallot, as listed above. However, the two that are of importance are the VSD (Number 1 above) and the narrowing in the pulmonary artery (“pulmonary stenosis”, number 2 above).

Tetralogy of Fallot is repaired by a congenital heart surgeon, who closes the VSD and opens up the narrowed pulmonary artery.