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

Abstract

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.

Keywords: 3‐D mapping; Advisor HD Grid mapping catheter; pivot point; slow pathway ablation; typical AVNRT; voltage‐gradient map.

FIGURE 1

Flowchart of the study. AVNRT, atrioventricular nodal re‐entrant tachycardia; CA, catheter ablation.

FIGURE 2

Voltage‐gradient and activation vector maps during sinus rhythm in a patient with typical AVNRT. (A) Voltage‐gradient map during sinus rhythm. A junctional rhythm can be observed around the tricuspid annulus (<0.5 mV) with the Jackman potential. (B) Activation vector map during sinus rhythm. Sinus impulses turn toward the tricuspid annulus side at the pivot point, wrap around the block line, and lie below the CS (arrow). Sites a and c, which are on opposite sides of the A‐wave, recorded at the reference electrode of the CS, are estimated to be located on opposite sides of each other relative to the block line. Site b exhibits a continuous and fractionated potential, indicating slow conduction at the pivot point. Red tags indicate the location where JR was identified. The waveforms differ for the potentials observed by the HD Grid and RF ablation catheter of Red tag (Red tag; HD Grid, Red tag; RF cath.). BL, block line; CS, coronary sinus; HD Grid, Advisor HD Grid SE; JR, junctional rhythm; RF Cath, radiofrequency ablation catheter; TA, tricuspid annulus. [Colour figure can be viewed at wileyonlinelibrary.com]