ACUTE CHANGE OF CARDIAC AUTONOMIC REGULATIONS AFTER THERMAL AND NON-THERMAL PULMONARY VEIN ABLATION (YOUNG INVESTIGATOR AWARD COMPETITION)

Background: Pulmonary vein isolation (PVI) by thermal energy results in collateral ganglionic plexi ablation. On the contrary, pulsed electric field (PEF) energy presumably spares neural tissue.

Objective: We investigated and compared the effect of PVI on parasympathetic input into the sinus node (SAN) and AV node (AVN) when four different ablation strategies were used.

Methods: A study enrolled 49 patients who underwent PVI in general anesthesia (age 57years, 71% males). In 17 patients, radiofrequency energy delivery by the irritated-tip catheter was used for ablation while 7 patients were ablated using a cryoballoon catheter. In 7 patients, PEF energy was delivered using a single-shot Farawave catheter while 18 patients were ablated using Sphere9 catheter. Before and after PVI, the responsiveness of the SAN and AVN was assessed by extracardiac vagal nerve stimulation (ECVS) via a diagnostic catheter in the right internal jugular vein. Stimulation was delivered both in sinus rhythm and during atrial pacing. Reduction of response to ECVS was arbitrarily defined as a maximum induced pause of

Results: At baseline, physiological response to ECVS (long sinus arrest and/or AV block) was demonstrated. After PVI, a substantial reduction of SAN response was observed in 21/24 (88%) patients after thermal PVI and 7/25 (25%) patients after non-thermal PVI (P = 0.0001). Similarly, a substantial reduction of AVN response was observed in 21/24 (88%) patients after thermal PVI and 9/25 (36%) patients after non-thermal PVI (P = 0.0003). The Figure shows on the continuous scale the post-PVI pauses in sinus rhythm (maximum P-P interval) and atrial pacing (maximum R-R interval) induced by ECVS.

Conclusion: Vagal responses of SAN and AVN are preserved in most AF patients after non-thermal PVI. This contrasts with the much stronger effect of thermal PVI.