Science Says: Kimmel baby's heart defect is common, fixable

Associated Press

The hole-in-the-heart problem that plagues comedian Jimmy Kimmel's newborn son is one of the most common heart-related birth defects, and it usually can be fixed with surgery.

Some people even live with it for several years before it's detected although the Kimmel baby's is the most severe form and was noticed just a few hours after his birth in Los Angeles on April 21.

On his show Monday night, the comedian tearfully described the emergency operation needed after his son, William John, was found to have tetralogy of Fallot.

Tetralogy means four, a cluster of that many defects. The main one is a hole or opening in the wall separating the two sides of the heart. In a normal heart, the right side pumps oxygen-depleted, or blue blood from other parts of the body to the lungs to get more oxygen. The left side then pumps this oxygen-rich, red blood to the rest of the body.

These types of blood should stay separated, but a hole in the heart wall lets them mix, so some blood without enough oxygen winds up getting pumped out into the body.

This can be complicated by a second problem the Kimmel baby has — pulmonary atresia, a severely blocked heart valve, which prevents enough blood from reaching the lungs.