Scope: Recent studies revealed that cardiac ganglio-nated plexi are ablated during pulmonary vein (PV) isolation for the invasive treatment of atrial fibrillation (AF). Reconnected PV found at repeated catheter ablation procedures are a marker of superficial lesions, with limited extension to ganglionated plexi that are located near PV. Deceleration capacity (DC) is an accurate electrocardiographic marker of parasympathetic tonus and recent studies revealed that DC is higher in patients with AF recurrence after catheter ablation proce-dure. Our aim was to evaluate the association between vagal tonus as assessed by DC and PV reconnection found at repeated catheter ablation procedure.

Methods: Consecutive patients who underwent an ini-tial cryoballoon ablation procedure for paroxysmal AF and underwent a repeated procedure with 3D electro-anatomic mapping for AF recurrence were selected. Of those, an additional 24-hours ambulatory ECG recording before the repeated ablation for DC measurement was required for inclusion.

Results: A total of 87 patients were included, of whi-ch 56 patients had reconnected PVs with a mean DC of 7.83 ± 3.04 ms, while the 31 patients with no reconnected PVs had a mean DC of 6.50 ± 2.49 ms (p=0.03, OR=1.49, 95% CI=1.21–1.70). DC correla-ted with number of reconnected PVs (p=0.04, r=0.54, 95%CI=0.39–0.68) and number of reconnected PVs was higher in cases with DC≥7.10ms than in cases with DC<7.10ms (median value used for dichotomization, p=0.01, OR=2.25, 95% CI=1.28 – 4.60). Patients with only left sided PVs reconnection had a mean DC of 5.87 ± 2.08 ms, while patients with only right sided PVs reconnection had a mean DC of 7.94 ± 3.10 ms (p=0.007). Also, DC predicted freedom from AF after initial cryoablation (p=0.01, HR=1.75, 95%CI=1.45– 2.01).

Conclusions: High parasympathetic tonus as assessed by DC associates with the presence of PV reconnection and correlates with number of reconnected PVs. Superficial lesions during cryoablation predispose to PV reconnection and implies incomplete ganglionated plexi denervation, explaining the relationship betwe-en high vagal tone as assessed by DC and reconnected PV. DC is highest in right sided PV reconnection and may be attributable to intact function of right anterior ganglionated plexus which is the final common vagal pathway to sinus node. In line with previous studies, DC predicted AF recurrence after initial cryoablation, reflecting that high vagal tone is involved intro AF recurrence.