July 25, 2012

3D Heart Maps Help Kids with Heart Rhythms

By: Katie Williams, Ivanhoe Health Correspondent

(Ivanhoe Newswire)- Researchers have completed the first study of a procedure which uses three dimensional maps to determine the location of electrical signals in children´s hearts. This could help cardiologists correct rapid heart rhythms in young patients.

Children who have atrioventricular nodal reentrant tachycardia, or AVNRT, suffer from disruptions in the heart's electrical system that causes sudden rapid heart rates. Patients have been successfully treated with cardiac ablation, in which the abnormal tissue that causes the condition is destroyed by freezing (cryoablation). However, the procedure can be difficult because every patient may have different areas of abnormal tissue that cause the arrhythmia. This is the first study to analyze this procedure on children.

"It used to be that we did anatomic guided ablation for these patients, so we would take catheters up into the groin and X-ray. We would determine where different structures were and we would try to ablate by burning or freezing the pathway, mostly burning the pathway. But in children, that area is a lot smaller and there´s a concern that we could actually burn or freeze the normal conduction," Lindsey Malloy, D.O., lead researcher and a cardiology fellow and researcher at University of Iowa Children's Hospital in Iowa City, told Ivanhoe.

Malloy and researchers created 3D voltage maps of the right atrium using electrical recordings from inside the heart. They identified a bridge of low voltage signals surrounded by even lower voltage tissue, a "saddle", which indicates reduced electrical activity.

The study included 29 patients between the ages of 7 and 20.

"In 25 of the 29 patients that I looked at, 25 of them had a voltage map that we used to guide us in our ablation therapy. In about 60 percent of the patients that we looked at, we were able to get rid of the arrhythmia from the AVNRT in the first 3 lesions, which is very good. We only had one patient of our 29 that came back and had a recurrent event of the AVNRT, and we had no patients that required a pacemaker," said Malloy.

Besides being the first study to look at this procedure in children, it also holds claim to findings that people can really identify with.

"Anatomical guidance uses radiation, and no mom or dad really wants our child to be exposed to radiation and or need a pacemaker, and we eliminated both of those."

Source: American Heart Association´s Basic Cardiovascular Sciences 2012 Scientific Sessions