Impact of ablation technologies on cardiac autonomic modulation in atrial fibrillation
M Caetano Coelho, SÉR GI O Laranjo, P E D R O Silva Cunha, H E L E N A Fonseca, MÁR IO Martins OliveiraAbstract
Introduction
Catheter ablation for pulmonary vein isolation (PVI) is an established treatment for atrial fibrillation (AF). Different energy sources—thermal such as cryoablation (CRYO) and radiofrequency (RF), and non-thermal such as pulsed field ablation (PFA)—may have distinct impacts on the cardiac autonomic nervous system (ANS), a factor with potential prognostic implications. This study aimed to compare the effects of PFA, CRYO, and RF on autonomic function and its temporal evolution.
Methods
We conducted a prospective observational study in 89 patients with predominantly paroxysmal AF undergoing PVI with either pulsed field ablation (PFA; n=11), cryoablation (CRYO; n=45), or radiofrequency (RF; n=33). The combined cohort had a mean age of 59 ± 10 years and was predominantly male (64%). Autonomic function was assessed through heart rate variability (HRV) analysis in time and frequency domains during a tilt table test protocol. Assessments were performed at baseline (pre-ablation) and at 1, 3, and 6 months of follow-up.
Results
The PFA group demonstrated minimal changes in HRV parameters (ΔHR, ΔSDNN, ΔRMSSD ≈ 0), suggesting preservation of autonomic function. In contrast, groups undergoing thermal ablation (CRYO and RF) showed a significant increase in heart rate and a marked reduction in global HRV indices (SDNN) and parasympathetic markers (RMSSD, PHF) (p<0.01), indicating substantial autonomic denervation. Longitudinal analysis revealed partial recovery of chronotropic response and a progressive increase in low-frequency power at 3 and 6 months in the thermal ablation groups, suggestive of adaptive autonomic remodelling and reinnervation over time.
Conclusion
Pulsed field ablation demonstrates a superior autonomic safety profile, preserving intrinsic cardiac function compared to thermal energy sources (CRYO and RF), which induce significant denervation. The distinct temporal evolution of autonomic modulation amongst technologies underscores the importance of long-term monitoring and may have implications for ablation strategy selection and arrhythmia recurrence risk stratification.For image description, please refer to the figure legend and surrounding text.