Last week, Jimmy Kimmel made a tearful and heartfelt announcement. His newborn son, Billy, was born with a rare heart condition--tetralogy of fallot, a congenital defect that affects just five in every 10,000 babies. We talked to Ramzi Nicolas, MD, associate professor of pediatrics, division director of pediatric and fetal cardiology, and associate chair of pediatric specialty services at SIU School of Medicine about Billy Kimmel's condition and what exactly it is.

What is tetralogy of fallot?

TOF is cardiac birth defect. According to the American Heart Association, it has four features: a hole between the lower chambers of the heart, an obstruction from the heart to the lungs, the aorta's placement over the hole in the lower chambers, and the muscle surrounding the lower right chamber being overly thickened. Its cause isn't known in most cases, though it's more commonly seen in children with chromosomal abnormalities. 

When is it diagnosed?

While it can be diagnosed before birth, Dr. Nicolas says the condition is always diagnosed in infancy. Dr. Nicolas says the condition is one of the defects associated with “blue baby” when a baby is born with a blue tint due to a lack of oxygen in the blood.

Is it deadly?

Unfortunately, it can be.

"If not surgically repaired it can lead to worsening delivery of oxygen to the tissue," Dr. Nicolas says. This can lead to what is known as "tet spells." These spells are caused by acute lack of oxygen and lead to shortness of breath, cyanosis (turning blue), agitation and loss of consciousness. These spells are dangerous and can lead to brain injury and early death.

Can it be fixed?

Thankfully, yes. The condition is repaired through open-heart surgery. There is a complete surgery that widens the pulmonary blood vessels and closes the hole in the septum. Most babies undergo the complete surgery, but for babies too small or weak, there is a temporary surgical procedure wherein a tube is placed causing an increase in oxygen. The complete surgery is then done when the child is older. According to the National Institutes of Health, thanks to advanced testing and treatments, Billy and other children born with TOF have a far better prognosis than in the past and, with surgery, most are able to survive to adulthood. Dr. Nicolas has treated children with TOF and other heart conditions at SIU Medicine since 2012.