Infant Heart, the Size of a Walnut, Rebuilt and Running

Jessica knew something was wrong with her fetus before he was born. A fetal ultrasound detected an abnormal heart and circulatory system. She was on bed rest for the last two months of the pregnancy.

Zachary was born nearly at term on Oct. 20 at a hospital in Knoxville. He was apparently healthy and weighed 8 pounds, 1 ounce. But the heart defect made his condition unstable, and he was immediately taken to the intensive care unit. Jessica did not hold him until he was more than two weeks old.

The aorta is the body's biggest artery. It leaves the heart's main pumping chamber -- the left ventricle -- and sweeps upward in an upside-down U, giving off arteries to the heart muscle, head and arms before heading down the chest into the abdomen to serve the lower body. This first part of the aorta just outside the heart is called the "aortic arch."

In Zachary's case, the arch did not exist as a single structure. The segment of the aorta that left the heart was abnormally narrow. The segment sent off two branches, the coronary arteries, which deliver oxygen and nutrients to the heart muscle. But then, instead of arching around and giving off many more branches, the aorta simply divided into two vessels, the carotid arteries, which send blood to the brain.

The part of the aorta that would normally have been the far end of the arch was attached to a structure called the pulmonary trunk. It gave off its usual branches. But it had no direct connection to the underdeveloped first part of the aorta.

The "interrupted aortic arch" was not the infant's only problem. There were others.

The valve that normally lets blood out of the left ventricle into the arch was permanently closed. Consequently, blood pumped by that ventricle went instead into the neighboring right ventricle through a large hole in the wall separating the two chambers. From there, it went out of the heart and eventually into the far end of the aortic arch.

A big question in this odd circuitry was how blood was getting to Zachary's coronary arteries. They normally receive blood just as it leaves the heart. But in his case, no blood left by that route.

It was still a mystery when one of Mary Donofrio's former cardiology trainees called her from a hospital at the University of Tennessee in Knoxville and said they had a baby whose problems were too complicated for doctors there to handle. It was only when the infant arrived in Washington by air ambulance at two days old and Donofrio did further tests that she was able to figure it out.

What she found was that Zachary's heart muscle was living off blood that went up the vertebral arteries to the brain, around a Beltway-like structure there called the "circle of Willis," and then down the carotid arteries in the opposite direction of the normal flow. At the end of this journey, the blood entered the dead-end stub of the aortic arch and fed the coronary arteries that came off it.

This long detour was something Jonas had never seen. He had just published a single-author text on the repair of heart defects -- a book with 300 drawings of anomalies and how to correct them -- so he was pretty sure he knew what had been reported by other surgeons over the years.

He checked the electronic database of journal articles again last week. He was right; the defect was unique.