Evaluation of oxidative stress biomarkers in patients undergoing catheter ablation for atrial fibrillation

Background Oxidative stress and inflammation play a crucial role in atrial fibrillation (AF) pathophysiology and may affect the response to catheter ablation. Experimental evidence suggests that oxidative pathways contribute to atrial remodelling and arrhythmia persistence; however, clinical data correlating oxidative biomarkers with procedural outcomes are limited. Purpose To assess changes in oxidative stress biomarkers, nicotinamide adenine dinucleotide phosphate oxidase 2 (Nox2) and hydrogen peroxide (H2O2), in patients undergoing catheter ablation for AF using radiofrequency (RF) or pulsed field ablation (PFA), and to explore their association with post-procedural arrhythmic recurrence. Methods This prospective observational study included 48 adults with non-valvular AF (19 treated with RF and 29 with PFA). Plasma Nox2 and H2O2 levels were measured in left atrial and peripheral venous samples collected immediately before and after ablation. Statistical analysis was based on non-parametric tests due to non-normal data distribution. Associations between biomarker levels and AF recurrence were evaluated using Spearman’s correlation. Results Post-procedural oxidative markers were significantly higher in the RF group than in the PFA group (Nox2: 53.6 ± 8 vs 35 ± 11 ng/mL, p < 0.001; H2O2: 56.6 ± 19 vs 37.2 ± 13 µmol/L, p = 0.004). The magnitude of change from baseline (Δ) was also greater after RF ablation (ΔNox2: 16.3 ± 7 vs −0.3 ± 2* ng/mL, p = 0.001; ΔH2O2: 19.4 ± 18 vs 1.6 ± 2 µmol/L, p = 0.002). No significant differences were observed in pre-procedural values between groups. A significant inverse correlation was found between post-procedural Nox2 levels and AF recurrence (r = −0.756; p = 0.030), while no correlation emerged for H2O2. Conclusions RF ablation induces a greater acute oxidative response compared with PFA, suggesting distinct biological effects of the two energy sources. The inverse association between post-procedural Nox2 and AF recurrence indicates a potential role of Nox2 as an early marker of ablation efficacy. Ongoing follow-up at 3 and 6 months, including analysis of inflammatory biomarkers (C-reactive protein, interleukin-6, tumour necrosis factor-α), will clarify the temporal interplay between oxidative and inflammatory responses and their impact on rhythm stability after ablation.