Tetralogy of Fallot is the most common type of congenital heart defect that causes babies to turn blue during their first months of life. The “tetralogy” in the name refers to four specific components that occur together: a large hole between the heart’s ventricles; a relatively large aorta that straddles the hole; narrowing of the pulmonary artery that delivers blood to the lungs; and abnormal thickening of the right ventricle. Our physicians have specialized training and a breadth of experience performing delicate, open-heart surgery in babies who require such medical assistance to address this condition. The surgery involves placing a Dacron patch over the hole between the ventricles, removing excess muscle in the right ventricle and possibly placing another patch over the area where the pulmonary artery connects to the right ventricle. In addition, the surgeon may also need to replace or repair the pulmonary valve and enlarge the branch of pulmonary arteries with a patch. Many children who receive this surgery may require an additional operation when they get older to replace the pulmonary valve if that valve develops significant leakage.