Haemolysis and renal safety profile of nanosecond pulsed field ablation in paroxysmal atrial fibrillation

Background Pulsed Field Ablation (PFA) is a novel non-thermal energy source that delivers high-voltage, ultra-rapid electrical pulses to create nanopores in cell membranes. This alters membrane permeability and disrupts cellular homeostasis, leading to apoptosis. Its high selectivity for myocardial tissue improves safety by sparing surrounding structures, avoiding the typical complications of radiofrequency or cryoablation. While conventional PFA systems deliver microsecond pulses, nanosecond PFA (nsPFA) represents one of the innovative technologies currently under investigation. Although considered generally safe, PFA has been linked to intravascular haemolysis and acute kidney injury (AKI), with incidence rates varying across different ablation catheter systems. Purpose The study aims to assess changes in haemolysis biomarkers and renal function after the use of nsPFA for paroxysmal AF. Methods Patients with paroxysmal AF were enrolled in this prospective, single-centre, open-label, non-randomized feasibility study. All patients underwent AF ablation with nsPFA, including pulmonary vein isolation (PVI) and posterior wall isolation (PWI), and received 1 L of Ringer’s lactate plus 1 L of 0.9% normal saline prior to the procedure. Laboratory markers of haemolysis (indirect bilirubin, lactate dehydrogenase [LDH], haptoglobin) and serum creatinine were assessed at baseline (T0) and 24 hours post-procedure (T1). Results A total of 43 patients (mean age 58.1 ± 9.6 years; 72.1% male) undergoing first-time AF ablation were included. Mean procedure, fluoroscopy, and left atrial dwell times were 36 ± 9, 17 ± 3, and 10 ± 4 minutes, respectively. Patients received an average of 18.5 ± 4.7 nsPFA applications. Acute PVI and PWI, confirmed by high-resolution electrogram mapping, were achieved in 100% of cases. At 24 hours post-procedure, significant variations in haemolysis markers were observed: +2.13 ± 1.81 mg/dL for indirect bilirubin, +284.9 ± 138.5 U/L for LDH, and −95.9 ± 41.4 mg/dL for haptoglobin (all p<0.001). However, renal function remained preserved under the hydration protocol, with no significant change in creatinine (+0.07 ± 0.45 mg/dL, p=0.317). Only one patient (2.3%) developed AKI requiring temporary dialysis after 33 nsPFA applications. No other major device-related complications occurred. A significant linear correlation was observed between the number of nsPFA applications and LDH increase (Pearson r = 0.70; p < 0.001), whereas haemolysis marker variations were not associated with age, BMI or baseline serum creatinine. Conclusions nsPFA is an effective and well-tolerated approach during PVI and PWI in patients with paroxysmal AF. In this series, a significant rise in haemolysis markers was observed, underscoring the need for careful monitoring of haemolysis and renal function following ablation with nsPFA.