Introduction: Periprocedural modulation of autonomic ganglionated plexus (GP) during pulmonary vein isolation (PVI) is considered to be an important
additional mechanism in the ablation of atrial fibrillation (AF). In this sub-analysis of the already concluded prospective randomized FreezeAF study,
we compared the extent of autonomic nervous system (ANS) modulation during cryo- and radiofrequency (RF) PVI and checked for a correlation with
long-term success of PVI.

Methods: ECGs pre- and post-PVI were extracted from EPU data sets of the FreezeAF study. The changes in deceleration capacity (DC) and periodic
repolarisation dynamics (PRD), established parameters for autonomic cardiac activity, during PVI were correlated with the type of ablation (cryo vs.
RF) and the freedom from AF after 6 and 12 months.

Results: 172 procedures were included for analysis (n=101 for cryo; n=71 for RF). We found an increase in PRD and a decrease in DC (indicating a
decrease in vagal activity) after PVI in general. In cryo-PVIs, ANS modulation was more pronounced than in RF ablations. While DC was significantly
lower after cryo- (p<0.01) and RF-PVI (p=0.042), a significant increase in PRD could only be shown for cryo-PVIs (p < 0.01; figure 1A). An analysis
of the change of ANS parameters pre- vs. post-PVI (increase or decrease) revealed no significant association with mid- and long-term outcome with
respect to freedom from AF (figure 1B).

Conclusion: In accordance with an assumed modulation of parasympathetic GPs, we found a decrease of vagal activity after PVI. Probably due to a
larger ablation area, ANS modulation was found to be higher in cryo-ablations. However, a prognostic relevance of ANS modulation could not be
observed in the studied cohort.