Voltage mapping for slow-pathway visualization and ablation of atrioventricular nodal reentry tachycardia in pediatric and young adult patients.

Voltage guidance for the ablation of the slow pathway in atrioventricular nodal reentry tachycardia (AVNRT) is a dramatic shift from the traditional anatomy-guided approach within the triangle of Koch. The use of voltage gradient mapping has been evaluated in adults as an aid to identification of the slow pathway guiding placement of ablation applications. This study aimed to evaluate this technique of voltage-guided ablation of AVNRT in pediatric and young adult patients, who have a smaller, more compact triangle of Koch. A retrospective cohort study evaluated patients 20 years of age or younger with AVNRT who underwent voltage mapping. Using NavX, three-dimensional voltage maps of the right atrium were created during sinus rhythm, focusing primarily on the triangle of Koch. The voltage map gradients were adjusted to uncover a "voltage bridge" of lower voltage signals. This bridge was used as a surrogate of the slow pathway to guide cryoablation at this site. Of the 31 patients who underwent voltage mapping, three were excluded from the study due to inadequate mapping. All the patients experienced procedural success. In 86 % of the patients, there was an adequate voltage bridge to allow guided ablation. The successful ablation site was within the first three lesions for 60 % of the patients. Two patients experienced recurrence during a median follow-up period of 14 months. It appears that voltage-guided ablation of a voltage bridge in AVNRT can be used effectively and safely in the pediatric population.