Late-night television host Jimmy Kimmel put the public spotlight on a rare congenital heart condition Monday with an emotional retelling of the drama surrounding the recent birth of his son, Billy. Just hours after Kimmel’s wife Molly gave birth, doctors diagnosed Billy with a combination of heart defects known as tetralogy of Fallot with pulmonary atresia, a condition that occurs in one out of every 2,000 babies. The defects affect the heart’s structure, allowing low-oxygen blood to flow from the heart to the rest of the body. This accounts for the bluish hue of Billy’s skin, which helped tip off his nurses that something was wrong.

Tetralogy of Fallot—named after French physician Étienne-Louis Arthur Fallot—is characterized by four malformations that occur in the heart as a fetus develops. These include a hole or holes in the wall between the heart’s lower chambers—the left and right ventricles—as well as a narrowing of the valve between the heart and lungs. Meanwhile, instead of branching away from the left ventricle, the aortathe main artery that carries oxygenated blood from the heart to the rest of the body—grows directly above the damaged wall between the ventricles, allowing deoxygenated blood from the right ventricle to mix with oxygen-rich blood from the left. The first three conditions set up the fourth, in which the wall of the overworked heart’s right ventricle thickens, causing the heart to weaken and eventually fail.

Pulmonary atresia is a severe form of the problem in which the valve allowing the outflow of blood from the heart to the lungs is completely closed. Poor maternal nutrition, viral illness or genetic disorders may increase the risk of the disease, but in most cases the cause is unknown, according to the Mayo Clinic.

During Monday night’s opening monologue Kimmel said Billy’s delivery was relatively easy and he initially appeared to be in good health. About three hours later, however, a nurse noticed the newborn had a heart murmur and that his skin was “turning purple.” An echocardiogram revealed the heart condition, and Billy was taken to Children’s Hospital Los Angeles for surgery to close the holes between the two ventricles.

The late-night host also turned his attention to the need for universal access to health insurance as well as funding for the kind of scientific research responsible for his son’s survival. Kimmel pointed out that Pres. Donald Trump had proposed a $6-billion cut in funding to the National Institutes of Health (NIH). “Thank God our congressmen made a deal last night to not go along with that,” he said. “They actually increased funding by $2 billion, and I applaud them for doing that.”

Scientific American reached out to Gerard Martin, a cardiologist and medical director of Global Health at Children's National Medical Center in Washington, D.C., to find out more about the disease.

[An edited transcript of the interview follows.]

What exactly is a heart murmur?

A murmur is the sound of blood passing through the heart or blood vessels. They can be innocent—the normal sound of blood passage—or they can be pathological murmurs caused by more turbulent flow, which indicates an abnormality of the heart. Innocent murmurs are present in up to 90 percent of children at some point in their life and are more common than pathological ones.

Are heart murmurs common in newborns?

Murmurs are common in infants. In newborns with a heart condition, however, murmurs are pathological. These can be due to holes in the heart or to blocked or leaky valves.

What does a purple or blue coloration of the skin tell doctors and nurses about a newborn?

Bluish discoloration of the skin is called cyanosis. This occurs when there is an abnormally low level of oxygen in the blood. Cyanosis—so-called “blue babies”—indicates that there is an abnormal structure of the heart with either a blockage in blood flow to the lungs (as seen in children with tetralogy of Fallot), abnormal arterial connections, abnormal venous connections or missing valves or chambers where the arterial and venous blood mix together. There are also other conditions, which can cause cyanosis—such as pneumonia or sepsis. 

How common is it for tetralogy of Fallot with pulmonary atresia to show up immediately after birth, as opposed to months or years later?

This condition typically presents within 24 hours of the child’s birth with symptoms such as breathing fast or not eating well, an abnormal physical examination, a heart murmur or cyanosis—a bluish discoloration of skin. Sometimes it can be difficult to see the cyanosis, particularly in cases in which the ductus arteriosus hasn’t closed. For these children, they are generally diagnosed prior to discharge with critical congenital heart disease screening.

Is there any way to identify this condition during pregnancy?

Many congenital heart defects can be identified before birth by a fetal ultrasound. Average rates of identification for critical congenital heart defects vary from 25 to 50 percent, but we are working with obstetricians to improve this rate. After birth care teams can also identify babies with congenital heart defects either by symptoms, abnormal physical examination or by critical congenital heart disease screening with pulse oximetry, which measures the blood’s oxygen level. Those types of screenings began in the U.S. over the past five to 10 years.

According to Kimmel, his son will have another open-heart surgery in three to six months to close the holes. How serious is that procedure?

Every child’s heart condition is unique but survival rates are generally 95 to 98 percent for a ventricular septal defect closure.

Kimmel also said his son will have a third, hopefully noninvasive, surgery in his teens to replace the valve he has now. What is the nature of that procedure?

For many children with tetralogy of Fallot with pulmonary atresia, the next procedure is called transvenous pulmonary valve implantation with a melody valve. This is a cardiac catheterization procedure in which a valve is inserted into the conduit that connects the right ventricle and the artery to the lungs.

What is the connection between funding to the NIH and the quality of health care in the U.S.? How significant is the $2-billion funding increase?

Research funding to NIH is critical for advancements in care. NIH dollars help to ensure we are continually improving and advancing pediatric medicine. At Children's National we use those dollars to make surgery less invasive, less painful and more effective for kids. This money supports intramural [studies at NIH] as well as extramural research [at universities], and it helps ensure children have access to the care that helps them grow up stronger.

With all eyes on health care, our country’s leaders have an opportunity to put the health and future of America’s children first. Currently, Medicaid covers more than 30 million children, and NIH funding helps to ensure advances in research, clinical trials and medical innovation. Continuing both of these programs is critical to ensuring our children have access to the care they need.