Combination of slow pathway late activation maps and voltage gradient maps in guidance of atrioventricular nodal reentrant tachycardia cryoablation

Background: The optimal strategy for electroanatomic mapping-guided cryoablation of atrioventricular nodal reentry tachycardia (AVNRT) remains unclear.

Objective: The purpose of this study was to investigate the effectiveness of slow pathway late activation mapping (SPLAM) and voltage gradient mapping for AVNRT cryoablation.

Methods: From June 2020 to February 2022, all consecutive patients with AVNRT underwent SPLAM to define the wave collision point and voltage gradient mapping to define the low-voltage bridge (LVB). Conventional procedures performed from August 2018 to May 2020 served as control.

Results: The study and control groups comprised 36 patients (age 16.5 ± 8.2 years) and 37 patients (age 15.5 ± 7.3 years), respectively. Total procedural times were comparable, and acute success rates were 100% in both groups. Compared to controls, the number of cryomapping attempts (median 3 vs 5; P = .012) and cryoablation applications (median 1 vs 2; P <.001) were significantly lower in the study group. At median follow-up of 14.6 and 18.3 months, recurrence rates were 5.6% (2 patients) and 10.8% (4 patients) in the study and control groups (P = .402), respectively. Mapping of the Koch triangle took 11.8 ± 3.6 minutes, during which 1562 ± 581 points were collected. In SPLAM, wave collision points were defined and compatible with the final successful lesion sites in all patients, including those with multiple slow pathways. LVB could not be defined in 6 patients (16.7%), and LVB was not compatible with the final successful lesion in another 6 (16.7%).

Conclusion: For AVNRT cryoablation, SPLAM could effectively guide the localization of slow pathway ablation sites and was particularly beneficial in patients with multiple slow pathways.