Kevin was born with a heart abnormality called Tetralogy of Fallot, which at one time would have been fatal in infancy. Thanks to several miraculous surgeries over several years, his heart was working well, and he celebrated his 17th birthday. His expectations, and those of his parents, were that he would live a long and healthy life, possibly even become a doctor to help kids in the same way he had been helped. He had even started to visit universities on weekends. While throwing a Frisbee with friends on a normal Thursday afternoon, Kevin’s heart began misfiring, a condition called arrhythmia. He suddenly collapsed and died before medical attention could arrive.

Erratic heart rhythms, or arrhythmias, claim more than 400,000 lives each year in the US. Dr. George Van Hare, the Louis Larrick Ward Chair in Pediatric Cardiology at St. Louis Children’s Hospital, studies arrhythmias in children. Dr. Van Hare came to Washington University School of Medicine from Stanford University to follow his passion for research in pediatric heart rhythm disorders, and to collaborate with world leaders in his search for answers.

George F. Van Hare, MD

Recently, Dr. Van Hare recently received a $200,000 Children’s Discovery Institute grant to bring a novel heart imaging technology to bear on pediatric heart problems. The technology, called electrocardiographic imaging (ECGI), creates a highly accurate picture of the electrical activity within the heart. It was developed by Yoram Rudy, PhD, the Fred Saigh Distinguished Professor of Engineering at Washington University and one of the world’s leading investigators on electrocardiographic imaging. 

With ECGI, 250 electrodes —as opposed to 12 electrodes in a standard electrocardiogram—are placed on a patient’s chest through a vest that is worn for approximately 30 minutes. The greater number of electrodes yields a more accurate electrical activity measurement than a standard electrocardiogram. The new process is called body surface mapping.

Once body surface mapping is complete, the patient undergoes a CT scan to measure the basic anatomy and size of the heart. After the CT scan, the electrical activity measurements are mapped onto this CT image of the heart, similar to wrapping plastic over an apple The result is a very accurate electrical representation of the patient’s heart that was obtained non-invasively. Traditional ways of gathering highly accurate electrical measurements are far more invasive.

“The way we do it as invasive cardiologists,” said Dr. Van Hare, “is to do heart catheterizations, where we place wires into the heart and move them around taking measurements. We then painstakingly construct a map of heart activation. This requires using sedation or anesthesia, invading the blood vessels, and at least several hours of painstaking work to compose the map.” In contrast, electrocardiographic imaging takes approximately 30 minutes of recording, requires no catheterization, and is painless to the patient.

One of the areas Dr. Van Hare wants to investigate via ECGI is how surgical scars affect electrical flow within a child’s heart. Children may have heart surgery for congenital heart disease, to correct malformations in one or more structures of the heart. While a normal heart has four chambers, a child with congenital heart disease may have only 2 or 3 chambers, or may have defects in the walls of the heart. Congenital heart disease affects 8-10 children out of every 1,000. Some of these children need multiple surgeries to correct their heart defects.

Surgery can save children’s lives, but the scars from surgery have been found to impede electrical signals that enable the heart to function. A normal heart pumps by filling up with blood and then contracting to force blood out to our bodies. This occurs because electrical activation begins first in the upper right chamber of the heart (right atrium). An electrical signal quickly spreads across the heart to the left atrium, causing a contraction, and then down into the two lower chambers called ventricles, which push blood out into the lungs and the rest of our body. This coordinated process requires a smooth wave of electrical firings that spread across the heart, much like “The Wave” at a baseball game.

Surgical scars can interrupt the wave, creating erratic heart rhythms. Electrical impulses can circle around surgical scars in an endless loop, causing an arrhythmia to occur with no warning. It’s the reason for the young man’s death in the beginning of this story. Dr. Van Hare believes ECGI may allow doctors to observe the electrical flow around surgical scars to better understand the root and the possible solutions to this difficult problem.

 “We can’t say to a surgeon: do the operation, but just don’t cut the heart,” said Dr. Van Hare. “But what we should be able to do is design the scars in such a way that they don’t create these electrical loops.” ECGI may also help doctors know where to place pacemaker leads to more effectively improve heart rhythm.

Even though ECGI offers great promise for children, the diagnostic tool is still not commonplace. At present, Washington University School of Medicine has only one ECGI unit, which is housed in the lab of Dr. Rudy. The need for another ECGI unit is immediate, to support Dr. Van Hare’s accelerating research and the School of Medicine’s recruitment of pediatric cardiology faculty member Jennifer Silva MD, who has extensive experience with ECGI.

Dr. Van Hare believes that research and clinical use of ECGI will take a multi-disciplinary approach, requiring the talents of experts in pediatric cardiology, electrophysiology, echocardiography, radiology, cardiac surgeons, as well as biomedical engineers like Dr. Rudy. By looking at a problem from many different disciplines and vantage points, the odds of finding solutions to help children will hopefully increase.

 “Washington University, Barnes-Jewish and Children’s Hospital have a glorious tradition of work in surgical management of arrhythmias. What’s unique about this place is you’ve got Yoram Rudy and his whole operation, you’ve got surgeons who understand the importance of surgery for managing arrhythmias, and now Dr. Jen Silva and I are here. Everything is coming together to hopefully find some solutions. For congenital heart patients to go through so many operations, to get to their teen years and suddenly die, that’s just horrible. We should be able to solve some of these things in my opinion, that’s why I think it’s important. That’s why I’m excited.” 

-George F. Van Hare, MD