3D Mapping Aids Heart Rhythm Therapy in Children

They demonstrated that by adding the 3D navigation system to a traditional x-ray based method to visualize electrophysiologic catheters inside the heart, they were able to successfully treat 99.1 % of 113 patients included in the study.

The most important finding was that the patients who were treated using the 3D computer navigation system were spared nearly 50% the radiation dose received by 108 comparable patients treated immediately before the new system was available. "The goal of reducing radiation dose is especially important in children, because of the risk it can pose to their health and fertility later in life,” stated Peter Fischbach, M.D., senior author of the new study and an assistant professor at the U-M Medical School.

The study utilized a mapping system known as LocaLisa, which uses a law of physics known as Ohm's law to localize a catheter in 3D space and inform clinicians where in the heart their catheters are situated. The LocaLisa system, developed by Medtronic (Minneapolis, MN, USA), revealed the catheter's location by passing an electrical current through the child's chest and measuring the interruption to that current created when the probe moves. That information is converted via a computer into a colorful 3D map that is displayed on a monitor in front of the clinician.

Even though x-rays are still required for part of the procedure, the new study demonstrated that the dose can be greatly reduced with the 3D mapping system. Interestingly, the 3D mapping system also allowed clinicians to reduce the number of RF applications they used to treat patients. In all, the treatment success rates from the two groups were statistically the same: 99.1% of LocaLisa patients were completely free from their rhythm problem after treatment, as were 97.2% of patients treated without the system. Neither group had major complications.

The patients in the study had an average age of 13 to 14 years, and about half were boys. Two-thirds of the patients had heart rhythm irregularities caused by accessory pathways--an additional electrical connection between the top and bottom chambers of the heart. One-third had atrioventricular nodal reentry tachycardia (AVNRT), a type of the most frequent rapid-heartbeat rhythm problem in adults.




Related Links:
University of Michigan Congenital Heart Center
Medtronic