Impact of pulsed field ablation on urinary tubular markers in patients with atrial fibrillation: a comparison with radiofrequency ablation

Background Acute kidney injury (AKI) related to hemolysis has been reported after pulsed field ablation (PFA) for atrial fibrillation (AF). However, few studies have investigated mild or subclinical renal injury without an increase in serum creatinine levels. Objective To clarify whether PFA induces mild renal tubular stress compared with radiofrequency ablation (RFA). Methods Between November 2024 and October 2025, a total of 383 consecutive patients who underwent initial AF ablation at our institution were enrolled. The PFA group consisted of 325 patients (155 with a pentaspline catheter and 170 with a circular multielectrode array catheter), and the RFA group included 58. Seven hemodialysis patients without urine output were excluded. Serum creatinine (Cr, mg/dL), urinary N-acetyl-β-D-glucosaminidase (NAG, U/L), and urinary α1-microglobulin (α1MG, mg/L) were measured 1–3 weeks before and the day after ablation. Plasma free hemoglobin (Free Hb, mg/mL) was measured at the beginning and immediately after the procedure. Results No patient in either group met the AKI criteria based on changes in serum creatinine. In the PFA group, the mean number of applications was 48 ± 5 with a pentaspline catheter and 53 ± 8 with a circular multielectrode array catheter. Urinary NAG, α1MG, and plasma Free Hb increased significantly after ablation: NAG increased from 3.5 (2.1–6.2) to 5.8 (3.1–9.3) U/L, α1MG from 3.7 (1.6–6.8) to 7.8 (3.4–17.5) mg/L, and Free Hb from 0.02 (0.01–0.03) to 0.03 (0.02–0.05) mg/mL (all p < 0.001). In contrast, the RFA group showed no significant changes in urinary markers: NAG 4.7 (1.4–8.2) vs 4.9 (1.9–8.7) U/L (p = 0.117), α1MG 3.5 (1.2–7.9) vs 3.8 (1.2–7.7) mg/L (p = 0.363), while plasma Free Hb significantly decreased from 0.02 (0.01–0.03) to 0.01 (0.01–0.02) mg/mL (p = 0.036). The increases in urinary tubular markers were not significantly associated with hemolysis or the number of PFA applications (Δα1MG vs ΔFree Hb: ρ = 0.033, p = 0.56; ΔNAG vs ΔFree Hb: ρ = 0.046, p = 0.41; pentaspline catheter count vs Δα1MG: ρ = 0.041, p = 0.61; pentaspline catheter count vs ΔNAG: ρ = –0.0606, p = 0.453; circular multielectrode array catheter count vs Δα1MG: ρ = 0.149, p = 0.0525 — showing a weak trend without statistical significance; circular multielectrode array catheter count vs ΔNAG: ρ = –0.0026, p = 0.973). Conclusion PFA for patients with AF induced a significant increase in urinary tubular markers (NAG and α1MG) and plasma Free Hb despite stable serum creatinine levels, whereas RFA caused no significant changes and even a slight reduction in plasma Free Hb. These findings suggest transient tubular stress after PFA; however, the relationship with hemolysis or application parameters was not clearly identified and requires further investigation.