Relationship Between Electrophysiological Changes and Clinical Efficacy of Slow Atrioventricular Nodal Pathway Ablation

To assess the relation between electrophysiological changes and clinical efficacy of slow atrioventricular(AV) nodal pathway ablation in patients with AV nodal reentrant tachycardia (AVNRT). Ninety four patients with slow fast AVNRT were treated by slow AV nodal pathway ablation. Electrophysiological study (EPS) was applied before?during and after ablation. End points of slow pathway ablation were evaluated. Ablation was successful in all patients. Of 94 patients, slow pathway conduction was completely blocked in 75 patients, not completely blocked in 19 patients. Of whom 2 had 1～2 AVN echoes. During follow up (mean 28±17 months), 4 patients had recurrent AVNRT 1～5 months after ablation and required second ablation. Five patients who had sustained junctional rhythm (JR) during delivery of radiofrequency (RF) energy still remained AVNRT after delivery of RF energy. The ablation was finally successful after changing ablation target. Time Titration was successfully accepted for 4 patients with aura of AV block during delivery of RF energy. [Conclusion] Ideal end point for slow pathway ablation should be no inducible AVNRT post ablation. The appearance of persistent JR is safe. To change ablation target could enhance the successful rate in a few patients. Time Titration is an optional way for these patients with aura of AV block during slow AV nodal pathway ablation, which could avoid permanent AV block.