Voltage-Gradient Mapping-Guided Slow Pathway Ablation in Typical Atrioventricular Nodal Re-Entrant Tachycardia.

Introduction: High-density mapping is useful for common atrioventricular nodal re-entrant tachycardia (AVNRT) ablation. This study aimed to evaluate the effective targets for slow pathway (SP) ablation using voltage-gradient mapping.

Methods: Fifty-two patients diagnosed with slow/fast AVNRT were enrolled. Patients underwent SP ablation using either a voltage-gradient map (n = 20) or a conventional approach based on anatomic and electrophysiological findings (n = 32). The Ensite X EP system was used as the 3-D mapping system in all patients. The target CA site was defined as the location at which the Jackman potential, with a voltage of <0.5 mV on the tricuspid annulus (TA) side of the pivot point, was confirmed by the creation of a voltage-gradient map with the Advisor HD Grid SE.

Results: The distance from the successful ablation site to the His bundle was significantly greater in the voltage-gradient map group (15.0 (12.8-19.0) vs. 11.0 (8.0-13.0) mm, p < 0.001), the junctional rhythm heart rate was slower (92.5 (78.8-121.8) vs. 114.0 (96.8-131.0) bpm, p = 0.028), and the time to the appearance of junctional rhythm after radiofrequency application was shorter (4.0 (2.5-7.3) vs. 7.8 (6.6-8.6) s, p = 0.002). Furthermore, the procedure time was also significantly shorter (53.5 (47.0-67.0) vs. 99.5 (76.3-112.5) min, p < 0.001) in the voltage-gradient map group.

Conclusion: The site at which the Jackman potential was confirmed, with a voltage of <0.5 mV on the TA side from the pivot point drawn using the voltage-gradient map, may be defined as the CA target of SP.