Safety and accuracy of the Rhythmia mapping system in pediatric patients

A new mapping system (Rhythmia) using a 64 mini-electrode small basket array (Orion) was developed that enables rapid high-density mapping in a short time. However, there are few reports about the usefulness of this system in pediatric cases.

The purpose of this study was to investigate the safety and accuracy of the Rhythmia system and Orion catheter in children.

Catheter ablation was performed using the Rhythmia system and Orion catheter in 23 patients younger than 20 years (body weight >20 kg) without a past medical history of cardiac disease. Mapping time, number of mapping beats, and number of mapping electrodes were compared for left atrium, right atrium and right ventricular outflow tract.

Twenty-three maps of the right atrium were acquired in 12.6 minutes (range 8.9-15.1), consisting of 709 beats (range 492-1163) and 7132 electrograms (range 4618-10,533). Twelve maps of the left atrium were acquired in 12.1 minutes (range 9.8-14.6), consisting of 565 beats (range 446-881) and 6412 electrograms (range 4912-11,402). There were no significant difference in mapping time, accepted beats, and electrograms between the 2 chambers. Manual annotation was needed in 53 of 293,185 electrograms (0.01%) due to far-field ventricular electrogram sensing and artifact. No adverse events occurred in any of the cases.

The Orion catheter and Rhythmia mapping system were safe and accurate for mapping various arrhythmias in pediatric patients. Detailed geometry and high-resolution activation mapping were acquired without the need for manual reannotation.