Different time course effect of autonomic nervous modulation after cryoballoon and hotballoon catheter ablations for paroxysmal atrial fibrillation.

Background: Few studies have reported on the quantitative evaluation of autonomic nerve modification after balloon ablation. Therefore, this study aimed to evaluate the effects of cryoballoon and hotballoon ablations on the autonomic nervous system (ANS) and their relationship with prognosis.

Methods: We included 234 patients who underwent cryoballoon ablation (n = 190) or hotballoon ablation (n = 44) for paroxysmal atrial fibrillation. Heart rate variability (HRV) analysis was performed on all patients using a 3-min electrocardiogram at baseline, 1, 3, 6, and 12 months after ablation. HRV parameters and prognoses were compared between the two balloon systems.

Results: Ln low-frequency (LF), Ln high-frequency (HF), standard deviation of the R-R intervals (SDNN), and RR intervals significantly decreased after 1 month in both groups, but the changes were more pronounced in the cryoballoon group than in the hotballoon group. In contrast, HRV indices in the hotballoon ablation group decreased gradually and reached their lowest point 3-to-6 months after the procedure, which was later than in the cryoballoon ablation group. The recurrence rate did not differ between the two groups. HRV parameters changed similarly in the cryoballoon group, regardless of recurrence. However, patients with recurrence had significantly higher SDNN and Ln LF at 12 months than those without recurrence in the hotballoon group (41.2 ± 39.3 ms vs. 18.5 ± 12.6 ms, p = 0.006, and 2.2 ± 0.7 ms² vs. 1.5 ± 0.7 ms², p = 0.003, respectively).

Conclusions: The time course of HRV changes differed between cryoballoon and hotballoon ablations. Hence, the two balloon systems may have distinct effects on the ANS and its role in prognosis.