Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with an increased risk of stroke and heart failure. The current gold standard method for catheter ablation treatment of AF is pulmonary vein isolation using radiofrequency ablation (RFA), in which high-frequency alternating current produces thermal injury to the tissue and isolates the arrhythmogenic area. Previous studies have shown a reduction in heart rate variability (HRV) parameters following RFA, which is presumed to be a result of thermal damage to the cardiac autonomic nervous system ganglia.
In recent years, pulsed field ablation (PFA) has emerged as a promising alternative to RFA. Unlike RFA, PFA is a largely non-thermal technique in which short, high-voltage electrical pulses induce irreversible electroporation and subsequent cell death due to loss of cellular homeostasis. Because cardiomyocytes have among the lowest thresholds for electric field sensitivity, PFA acts selectively on myocardial tissue and, according to current evidence, preserves the autonomic ganglia to a greater extent.
The aim of this work was to compare HRV parameters in patients after catheter-based pulmonary vein isolation performed using RFA and PFA. The study included 7-day Holter ECG recordings obtained 3, 6, and 12 months after ablation. Time-domain, frequency-domain, and non-linear HRV parameters were calculated using Kubios HRV Scientific software, and statistical analysis was performed in MATLAB. HRV parameters were compared between the RFA and PFA groups at each time point, as well as within each group over time (3, 6, and 12 months after ablation).
Our results showed that three months after ablation, HRV parameters were significantly lower and less dispersed in the RFA group compared to the PFA group, which is consistent with the hypothesis that PFA better preserves parasympathetic function and exerts a milder effect on cardiac autonomic regulation. The most prominent differences were observed in time-domain parameters RMSSD, SDNN, SDNNI, frequency components LF, HF, and nonlinear indices SD1, SD2. Six months after the procedure, the intergroup differences became less pronounced but remained statistically significant, mainly in parasympathetic-related parameters (RMSSD, SD1). Twelve months after ablation, no statistically significant differences were observed between the groups, although some HRV parameters remained close to the level of significance.
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Repeated-measures ANOVA confirmed that SDNN, SDNNI and SD2 increased statistically significantly over time only in the RFA group, whereas parameters in the PFA group remained stable.
Our findings complement the existing evidence from the literature and demonstrate that after RFA, HRV parameters initially decrease and then gradually increase over a 12-month follow-up period. These time-dependent changes in HRV can be explained by transient denervation followed by partial reinnervation. In the PFA group, no significant temporal changes in HRV parameters were observed, suggesting that PFA likely preserves a more stable parasympathetic and sympathetic regulation compared to RFA. From a physiological perspective, preservation of parasympathetic activity after PFA is important, as it contributes to cardiovascular homeostasis, reduces the risk of arrhythmogenic triggers and modulates the response to physiological stress. Altogether, these findings support the potential of PFA as a safer and more selective alternative to thermal ablation techniques and provide a better understanding of its clinical relevance.
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