Impact of energy source for pulmonary vein isolation on heart rate variability and autonomic modulation

Introduction Autonomic nervous system modulation has emerged as a potential therapeutic target in atrial fibrillation(AF) management. Ganglionated plexi located in the left atrium may be affected by energy application around the pulmonary veins during catheter ablation, potentially altering autonomic tone. Heart rate variability(HRV) provides a non-invasive assessment of autonomic function and has been used to evaluate autonomic changes following thermal ablation. However, HRV changes following non-thermal ablation remain underexplored. Purpose This study aimed to investigate differences in heart rate(HR) and HRV parameters following pulmonary vein isolation(PVI) for AF performed with either cryoballoon ablation(CBA) or pulsed field ablation(PFA). Methods In this prospective, single-center study, patients undergoing first-time catheter ablation for AF using a PVI-based strategy were included. The first group underwent CBA using a cryoballoon with overinflation capability. The second group underwent PFA using a system with two configurations(basket and flower). Standard 24-hour Holter monitoring was performed 24 hours before ablation and repeated three months post-procedure. HR and HRV parameters, including mean RR interval, standard deviation of normal-to-normal intervals(SDNN), standard deviation of average NN intervals in 5-minute segments (SDANN), percentage of successive NN intervals differing by >50ms(pNN50), root mean square of successive differences(RMSSD), and the mean of 5-minute standard deviations of NN intervals(SDNN index), were assessed at both timepoints for each group. Results A total of 33 patients were included (CBA: n = 18; 38.9% female; mean age = 62.4 ± 11.5 years; 83% paroxysmal AF; mean AF duration = 7.53 ± 6.89 years; PFA: n = 15; 40.0% female; mean age = 66.2 ± 6.9 years; 100% paroxysmal AF; mean AF duration = 3.91 ± 3.85 years). Baseline clinical characteristics did not differ significantly between groups. At three-month follow-up, the CBA group demonstrated significant reductions in both overall and short-term HRV parameters, including decreased SDNN, SDANN and pNN50, with a trend towards a reduced SDNN index. Minimum and average heart rates also increased significantly. No significant changes were found in supraventricular extrasystole burden and RMSSD. In contrast, the PFA group exhibited no significant changes in HRV time-domain indices or arrhythmia burden at follow-up(Table 1). Conclusion CBA may have a more pronounced effect on autonomic modulation compared to PFA in the early post-ablation period. This difference highlights the potential role of energy source selection in tailoring AF management, particularly in patients where autonomic neuromodulation might improve clinical outcomes. In the emerging era of dual-energy catheters, the integration of thermal and non-thermal ablation modalities could enhance PVI procedures, potentially optimizing procedural efficacy and long-term rhythm control.