Relationship between CARTO late annotation mapping and successful cryoablation sites in typical atrioventricular nodal reentrant tachycardia

Background Precise localization of the slow pathway potential is essential for successful catheter cryoablation of typical atrioventricular nodal reentrant tachycardia (AVNRT). However, objective electrophysiological markers that reliably identify optimal ablation targets remain limited. Objectives This study aimed to evaluate the spatial relationship between the most delayed atrial potential (MDAP), identified using the CARTO 3 late annotation mapping (LAM) module, and successful cryoablation sites in patients with typical AVNRT. Methods We retrospectively analyzed 20 consecutive patients who underwent slow-pathway cryothermal ablation for typical AVNRT between June 2023 and June 2024. Before ablation, high-density electroanatomical mapping of Koch’s triangle was performed during high right atrial pacing using an OCTARAY™ catheter and the CARTO 3 system. Ablation was delivered anatomically with a cryocatheter under fluoroscopic and local electrogram guidance, without real-time LAM guidance. Post-procedural LAM analysis identified the MDAP, and its three-dimensional distance from the successful ablation site was measured. Results Acute procedural success was achieved in all patients (20/20, 100%) with no major complications or permanent atrioventricular block. The mean distance between the MDAP and successful ablation site was 2.7 ± 2.1 mm. In 4 patients (20%), the MDAP and ablation site were concordant (0 mm). Conclusions The most delayed atrial potential identified using CARTO LAM closely corresponds to successful slow-pathway ablation sites in patients with typical AVNRT. These findings suggest that LAM represents a robust and electrophysiologically meaningful marker of slow pathway localization and may enhance the precision and reproducibility of AVNRT ablation.