3-D maps of electrical signals may help correct rapid rhythms in children

The first study of a procedure to make 3-D “maps” of electrical signals in children’s hearts could help cardiologists correct rapid heart rhythms in young patients, according to new research presented at the American Heart Association’s Basic Cardiovascular Sciences 2012 Scientific Sessions.

The study was conducted in children with atrioventricular nodal reentrant tachycardia (AVNRT). Patients with this condition have been successfully treated with cardiac ablation, but this can be a difficult procedure because every patient may have a different area of abnormal tissue causing the arrhythmia, so low-voltage mapping is used to create a profile of high- and low-voltage areas of tissue to guide ablation, according to information in a press release.

“This is the first study to look at this technique in pediatric patients,” Lindsey Malloy, DO, a cardiology fellow and researcher at University of Iowa Children’s Hospital, stated in the release. “It has the potential to improve ablation success rates.”

The study included 29 patients aged 7 to 20 years (10 boys) with AVNRT who underwent voltage mapping within the slow pathway area. Malloy and colleagues created 3-D voltage maps of the right atrium using intracardiac electrical recordings. Then, a voltage map was used to identify a bridge of lower voltage signals that were surrounded by even lower voltage tissue; the bridge was used to guide cryoablation of the slow pathway, according to the study abstract.

Procedural success, defined as no inducible AVNRT and single AV node echo beat or less, was observed in all of the 29 patients who underwent AVNRT ablation with voltage mapping. In 25 of 29 patients, there was an adequate voltage bridge to allow guided ablation, while the successful ablation site was within the first three lesions in 15 of 25 patients, according to the press release. The number of total lesions ranged from five to 34. The researchers noted recurrence in one patient during an average follow-up of 1 year.

“The use of voltage-guided ablation of a low-voltage saddle in AVNRT is a technique that appears to be effective and safe in the pediatric population and has the advantage of allowing an electrically-guided ablation therapy,” the researchers concluded in their study.

For more information:

Malloy L. Abstract #25. Presented at: the American Heart Association Basic Cardiovascular Sciences Scientific Sessions 2012; July 23-25, 2012; New Orleans.

Disclosure: Dr. Malloy and colleagues report no relevant financial disclosures.