An observational study on efficacy of atrioventricular nodal slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia and its influence on atrioventricular conduction function

The study aimed to evaluate the effectiveness of atrioventricular nodal slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia (AVNRT) and examine its impact on the atrioventricular conduction function. A retrospective analysis was performed on the clinical data of 90 AVNRT patients who underwent radiofrequency ablation at our institution between August 2018 and February 2021. Based on the presence or absence of slow pathway conduction during the procedure, patients were classified into the slow pathway elimination group (SPE group) and the slow pathway improvement group (SPI group). Procedure-related parameters, His bundle electrogram, atrioventricular nodal effective refractory period (AVN-ERP), Wenckebach point of anterograde atrioventricular nodal conduction (AVN-WKB), Wenckebach point of retrograde atrioventricular nodal conduction (VAV-WKB), myocardial function were compared between the 2 groups. Additionally, the recurrence rates 1 and 2 years post-ablation were noted. Both groups reported a 100% success rate for the procedure. Post-ablation, 42 patients exhibited persisting atrioventricular nodal slow pathway, whereas 48 showed its disappearance, signifying the absence of the jump phenomenon and atrial echo. Post-ablation, the SPI group showed an increase in slow pathway AVN-ERP compared to pre-ablation values (P < .05), with no significant change in the fast pathway AVN-ERP (P > .05). The SPE group showed a reduction in both slow pathway and fast pathway AVN-ERP post-ablation (P < .05). Post-ablation, both slow pathway and fast pathway AVN-ERP in the SPI group were higher than in the SPE group (P < .05). AVN-WKB and VAV-WKB values increased in both groups after ablation (P < .05). There were no recurrences 1 or 2 years after ablation in the SPE group and 1 case of recurrence 2 years after ablation in the SPI group (2.38%). Different ablation endpoints during radiofrequency ablation had no apparent impact on atrioventricular conduction time, recurrence rate, and myocardial function in patients with AVNRT, but they advanced AVN-WKB and VAV-WKB. Slow pathway improvement led to an elongation of slow pathway AVN-ERP, while slow pathway elimination resulted in a reduction of both slow pathway and fast pathway AVN-ERP.