Hemolysis after atrial fibrillation ablation conducted with a new point-by-point pulsed field ablation device

Background/Introduction
Pulsed field ablation (PFA) has gained traction in recent years as an alternative to thermal ablation techniques, such as radiofrequency (RF) and cryoballoon ablation (CBA), due to its non-inferior efficacy(1)  and potential safety advantages in atrial fibrillation ablation (PVI). Cardiomyocytes are particularly susceptible to electroporation, whereas non-cardiac tissues are relatively resistant to the electrical fields used in this technique(2). However, there have been reports of hemolysis and even kidney injury resulting from hemolysis following PFA with a pentaspline catheter, especially when an above-average number of pulses were delivered during a procedure or when the patient had preexisting kidney impairment(3).

Purpose
To date, only single-shot PFA systems, which are designed to generate large electrical fields, have been evaluated for hemolysis. We therefore aimed to assess how the point-by-point Affera® Mapping and Ablation system (Medtronic) affects hemolysis and kidney injury.

Methods
16 consecutive Patients who underwent PVI with the Affera mapping and pulsed field ablation system in the DHZC were included. Blood samples were drawn the day before and the day after the procedure. Hemoglobin, reticulocytes, LDH, haptoglobin, indirect bilirubin, and creatinine were measured, and their changes from pre- to post-procedure were correlated with the number of ablation pulses delivered.

Results
16 patients were analyzed (62,5% male, mean age 65,2 ± 8,46 years, 8 first PVI, 8 Redo- PVI with/without additional substrate modification, 58,5 ± 29,33 pulses delivered).
Hemoglobin (14,66 g/dl ± 0,94 to 12,91 g/dl ± 1,87; p<0,001) and haptoglobin (1,04 g/l ± 0,19 to 0,87 g/l ± 0,38; p=0,017) decreased, while indirect bilirubin (0,54 mg/dl ± 0,39 to 0,75 mg/dl ± 0,39; p=0,036) increased. Reticulocytes, LDH and creatinine did not differ significantly (p=0,176, p=0,11 and p=0,91 respectively).
None of the parameters, that had a significant change, had a significant correlation with the pulsed field pulses delivered.

Conclusion
This was a first analysis of hemolysis induced by the novel point-by-point pulsed field ablation device used at our center after atrial fibrillation ablation. We detected signs of very little hemolysis, however this was, at least for now, independent of the pulsed field pulses delivered. Importantly, there was no decrease in kidney function.