Introduction: Catheter ablation is a key treatment for atrial fibrillation (AF). Yet, its impact on cardiac autonomic modulation, which contributes to AF initiation and maintenance, may vary depending on the ablation modality. This study compares the effects of cryoablation (CRYO) and pulsed field ablation (PFA) on heart rate variability (HRV) indices, which serve as markers of autonomic function.
Methods: 10-minute, 12-lead ECG recordings of 54 patients (61% PFA, 63% male) were acquired before (pre) and 3 months after (post) ablation. Time-domain (SDNN, RMSSD) and frequency-domain (P_LF, P_HF, P_(LF/HF)) indices were calculated, and intra- and inter-group differences were assessed.
Results: Before ablation, HRV indices were comparable between groups. After ablation, CRYO patients exhibited a significant (p<0.05) reduction in time- and frequency-domain indices (median reductions: -10.5 ms SDNN, -4.8 ms RMSSD, -2.3x10^(-4) P_LF, -1.0x10^(-4) P_HF), indicating substantial autonomic modulation. In contrast, the PFA group showed non-significant HRV changes from baseline (-1.62 ms SDNN, -2.80 ms RMSSD, -0.32x10^(-4) P_LF), and a significant but lower reduction in P_HF (-0.47x10^(-4)), suggesting preserved autonomic function.
Conclusion: While CRYO appears to attenuate ganglionated plexi activity, potentially reducing post-procedural arrhythmogenic triggers, PFA largely preserves autonomic input, which can promote AF recurrence.