Outcomes of Catheter Ablation for Typical Atrioventricular Nodal Reentrant Tachycardia with Low Power Energy of 20 W: A Prospective Multicenter Study

Background Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common form of supraventricular tachycardia, and catheter ablation is a well-established treatment. However, the risk of atrioventricular (AV) block requiring permanent pacemaker implantation remains a significant concern, with reported incidence rates ranging from 0.1% to 0.8%. Objective This study aimed to assess the clinical outcomes and safety of slow pathway ablation using low-power energy (20 W) for typical AVNRT. Methods This prospective multicenter trial enrolled 203 patients (mean age 54.4±17.3 years, 121 women) who underwent slow pathway ablation with 20 W between May 2017 and February 2022. Ablation was performed from the posterior region of the triangle of Koch until a slow-accelerated junctional rhythm was observed. Results Among the 203 patients who underwent ablation, 170 (83.7%) achieved successful ablation with 20 W. Of the 33 patients (16.3%) who did not achieve success with 20 W, 17 (8.4%) required 25 W, while 16 (7.9%) required an energy level greater than 25 W. A younger age (43.8±17.1 vs. 56.4±16.5 years, p<0.001) and a higher pre-ablation heart rate (84.8±11.8 vs. 77.3±10.8 bpm, p<0.001) were associated with failure at 20 W. Transient AV block occurred in 4 patients (1.9%). No patients developed permanent AV block requiring pacemaker implantation. The recurrence rate following low-power ablation was 0.9%. Over a mean follow-up of 18.3±4.1 months, no long-term complications were reported. Conclusion Low-power ablation using 20 W is a safe and effective strategy for typical AVNRT, with no cases of permanent AV block observed in this cohort.