Randomized investigation of the left atrial sweet spot for vagal denervation of atrioventricular node during the cardioneuroablation

Background Radiofrequency catheter ablation of inferior atrial ganglionic plexi frequently results in vagal denervation of the atrioventricular (AV) node. The effective sites are, however, considerably variable. Purpose We prospectively sought the left atrial (LA) ablation site with the maximum effect on AV nodal modulation. Methods The study included 16 patients (age: 46±14 years, 56% males) who underwent cardioneuroablation for recurrent reflex cardioinhibitory syncope in general anesthesia. After targeting the superior paraseptal ganglionic plexi and achieving the denervation of the sinus node, study ablations were performed at the bottom of the LA to accomplish the AV nodal denervation (Figure). Five equidistantly distributed ablation lesions (30W / 30s / 20ml/min) were created on the virtual line connecting inferior ostium of right inferior pulmonary vein (RIPV) and inferior mitral annulus (MA). Lesions were centered symmetrically relative to the posterior mid-left-atrial line. They were numbered in ascending order from #1 (more septal, closer to the RIPV) to #5 (more lateral, closer to the MA). Patients were randomly (1:1) assigned to mutually opposite direction of ablation (from site #1 to #5 or from site #5 to #1). The response of heart rhythm to extracardiac vagal nerve high-frequency stimulation (50Hz/0.05ms/1V/kg [ Results Study protocol ablations overall resulted in elimination or attenuation of inducible AV block (maximum R-R interval: 2.9±2.8 vs. 5.2±2.4s, P Conclusion Ablation of perimitral region of the inferior LA conveyed the maximum effect in terms of AV nodal denervation. Funding Acknowledgement Type of funding source: None