Unexpected acute kidney injury requiring dialysis after routine pulsed field pulmonary vein isolation: a case report.

Background: Pulmonary vein isolation (PVI) using pulsed field ablation (PFA) has emerged as a promising treatment for atrial fibrillation (AF). However, haemolysis-induced acute kidney injury (AKI) remains a concern, particularly with higher numbers of applications. Case summary: We report the case of a 62-year-old male with a history of CABG who underwent PVI using a 35 mm pentaspline PFA catheter. Pre-procedural CT imaging revealed a large 37 mm left common PV ostium. Standard energy delivery protocols were followed, including two 'olive' applications per vein. The patient was discharged the same day. That evening, he developed dark 'cola-coloured' urine. Upon remote consultation the next day, he was advised to increase fluid intake to 3 L that day. His urine colour normalized by the following day, but he experienced a 3 kg weight gain and oliguria and presented to the emergency department. Laboratory tests showed severe AKI (eGFR to 6 mL/min/1.73 m²), necessitating urgent dialysis. Laboratory results showed modest but clinically relevant elevation of haemolysis markers, while urine analysis showed breakdown product of erythrocytes. After several haemodialysis sessions, the patient's urine output improved, and he was eventually discharged. Two months after the procedure, his renal function recovered to normal values. Discussion: While prior experience suggests that limiting PFA applications to fewer than 70 may reduce the risk of haemolysis-associated renal injury, this case demonstrates that even with 40 applications and minimal systemic haemolysis, AKI requiring dialysis can occur. This highlights the need for heightened vigilance, early fluid management, and prompt intervention to support renal recovery after PFA.