Objective. To evaluate the incidence, characteristics, and impact of the vagal response (VR) observed during radiofrequency ablation on the course of paroxysmal atrial fibrillation (AF) during pulmonary vein isolation (PVI) procedures and the ganglionic plexus (GP) ablation followed by PVI. Material and methods. A total of 136 patients (ME age 50.8 [46.4; 54.0] years; 59.6% men) with symptomatic paroxysmal AF refractory to antiarrhythmic therapy were included in a bidirectional (retro- and prospective) study. Depending on the treatment strategy, two main groups were identified: group 1 – PVI (n = 75), group 2 – GP ablation followed by PVI (PVI + GP). The groups did not differ in the main clinical and demographic parameters. All patients underwent an electrophysiological study and navigated electroanatomical mapping. Fractionated electrogram mapping and anatomical criteria were used to determine the sites of GP localization and ablation. The follow-up period was 19.6 ± 5.8 months. The primary endpoint was freedom from AF or other persistent forms of atrial tachycardia (AT), confirmed by electrocardiographic monitoring. To assess the impact of VR on the prognosis of AF recurrence, Kaplan–Meier and Cox regression analyses were performed. Results. Complete electrical isolation of the PVs was achieved in all patients in both groups. Based on the results of ablation, patients were further divided into subgroups: with and without the presence of VR at the time of ablation. In the PVI + GP group, positive VR was observed more frequently than in the PVI group (49 (80.3%) versus 46 (61.3%), p = 0.027). At the end of the procedure, patients with positive VR in the PVI + GP group had significantly shorter basal cycle length (BCL), corrected sinus node recovery time (CSNRT), and Wenckebach cycle (WC) length of the AV node course compared with a similar subgroup of patients in the PVI group (732.3 ± 91.7 ms vs. 769.5 ± 95.4 ms, 396.7 ± 74.7 ms vs. 452.2 ± 87.6 ms, and 364.7 ± 25.6 ms vs. 411.8 ± 26.7 ms; all p < 0.001). Cohort analysis showed that ablation was associated with an increased rate of AF recurrence at 24 months in patients without VR compared with patients with VR (hazard ratio 1.802, 95% confidence interval 1.164–2.90). A separate Kaplan-Meier subgroup analysis showed a statistical difference in favor of patients with VR only in the PVI + GP group (log rank p = 0.028), with a better long-term outcome. No significant difference in ablation efficacy was found between the subgroup with and without VR in the PVI group (log rank p = 0.336). Conclusion. The occurrence of VR during radiofrequency catheter ablation is accompanied by changes in electrophysiological parameters after the procedure, consisting of a decrease in the BCL duration, CSNRT, and WC length of the AV node. These changes are most pronounced in patients after the PVI + GP procedure. Regardless of the ablation strategy, intraoperative VR was frequently observed in the entire cohort and appears to indicate a more favorable prognosis 24 months after ablation. However, subanalysis data showed that only in the PVI + GP group did positive VR significantly reduce the long-term recurrence rate of AF, which should be taken into account when developing antiarrhythmic treatment.