Jimmy Kimmel experienced one of the most difficult times of his life when nurses and doctors noticed his newborn child, Bill had a heart murmur and had a blue color to his skin. Nothing prepares an expectant parent for bad news. But that experience became part of a national discussion recently, with the news that Jimmy Kimmel’s son was diagnosed with a congenital heart defect called tetralogy of Fallot with pulmonary atresia.Jimmy Kimmel and son Billy

The talk show host shared his emotional story after his son Billy’s first surgery in April and a second one earlier this month. His monologues highlighted hot-button issues about health care but also gave a national spotlight to a rare heart condition.

Off the Charts is a series featuring expert answers to questions about heart and brain health. This week we explore tetralogy of Fallot with pulmonary atresia.

Q: So, just what is tetralogy of Fallot with pulmonary atresia?

A: Tetralogy (teh-TRAL-o-je) of Fallot (fah-LO) is named for French physician Étienne-Louis Arthur Fallot and is a serious heart condition that occurs in five of every 10,000 babies. The more severe form with pulmonary atresia occurs in about one out of every 10,000 babies, according to the Centers for Disease Control and Prevention.