Peri-Procedural Intravascular Hemolysis during Atrial Fibrillation Ablation: A Comparison of Pulsed-Field with Radiofrequency Ablation

Background Despite the favorable safety profile of pulsed-field (PF) energy during ablation of atrial fibrillation (AF), infrequent cases of renal failure, probably caused by hemolysis, have been recently described. The aim was to analyze hemolysis in patients undergoing pulmonary vein isolation (PVI) with PF ablation (PFA) or radiofrequency ablation (RFA). Methods In consecutive patients, PVI was performed with PFA or RFA. Blood samples were drawn pre-procedure, immediately post-ablation, and one day post-ablation. The concentration of red blood cell microparticles (RBCμ, fragments of damaged erythrocytes) in blood was assessed using flow cytometry (identified as CD235a and annexin V positive events). Lactate-dehydrogenase (LDH), haptoglobin and indirect bilirubin were measured at baseline and at 24 hours. Results Seventy patients (age 64.7±10.2, 47% women, 36 [51.4%] paroxysmal AF) were enrolled, 47 patients in the PFA group (22 PVI only, 36.4±5.5 PF applications vs. 25 PVI plus additional ablations, 67.3±12.4 PF applications). Twenty-three patients underwent RFA. Compared to baseline, the RBCμ concentration increased ~ 12-fold post-PFA, and returned to baseline by 24 h (70.8 Nr/μL, 51.8-102.5 vs. 846.6; 639.2-1,215.5 vs. 59.3; 42.9-86.5 Nr/μL, p<0.001); this increase was greater in PVI-plus compared to PVI-only patients (p=0.007). There was also a significant albeit substantially smaller peri-procedural increase in RBCμ with RFA (77.7; 39.2-92.0 vs. 149.6; 106.6-180.8 vs. 89.0; 61.2-123.4,p<0.001). At 24 h with PFA, the concentration of LDH and indirect bilirubin increased, and of haptoglobin decreased highly-significantly (all p<0.001). Only smaller changes in LDH and haptoglobin concentrations (p=0.03), and no change in bilirubin concentrations were present with RFA. Conclusion PFA was associated with significant peri-procedural hemolysis. The number of PF applications should be minimized.