Hemolysis After Pulsed Field Ablation With a Variable-Loop Irrigated Circular Catheter

Hemolysis is a recognized complication of endocardial pulsed field ablation (PFA), and its severity is influenced by factors such as the number of applications, tissue contact, and characteristics of the PFA system. However, most existing data are based on the Pentaspline catheter, and limited information is available regarding hemolysis with other PFA systems.

We evaluated hemolysis in seven consecutive patients with paroxysmal atrial fibrillation undergoing PFA using a variable-loop irrigated circular catheter (VLCC; Varipulse, Biosense Webster) and a dedicated generator (TRUPULSE). All procedures included pulmonary vein and posterior wall isolation, guided by a tissue proximity indicator (TPI). A median of 32 applications was delivered per patient. Plasma-free hemoglobin levels significantly increased from 0.01 (0.00-0.01) g/dL before the procedure to 0.05 (0.04-0.06) g/dL after the procedure (p < 0.001). Post-procedural reductions in hemoglobin levels and increases in bilirubin and lactate dehydrogenase levels were also observed, along with subnormal haptoglobin levels in 50% of patients. Creatine kinase levels increased significantly from 84 (82-146) U/L preoperatively to 323 (272-369) U/L postoperatively (p = 0.018). No cases of acute kidney injury occurred, and renal function remained stable post-procedure.

This is the first study to evaluate hemolysis with a VLCC-based PFA using plasma-free hemoglobin as a biomarker. These findings underscore the importance of evaluating each PFA system individually to better understand their safety and biophysical effects.