Biological Interpretation of Differential Biomarker Responses After Pulsed Field and Cryoballoon Ablation

The authors showed valuable comparative data on systemic inflammatory and myocardial biomarker responses between a novel balloon-in-basket pulsed field ablation (BiB-PFA) system and the well-established cryoballoon ablation (CB) technique [1]. As the authors discussed, the finding that BiB-PFA was associated with a greater rise in myocardial injury biomarkers, whereas CB induced a stronger inflammatory response, is intriguing and likely reflects fundamental differences in energy delivery mechanisms. This observation provides important mechanistic insight into the biological effects of thermal versus non-thermal ablation technologies. Nevertheless, several points merit further clarification and discussion. There was a significant age difference between the two groups, with patients in the CB group being older than those in the BiB-PFA group [1]. Aging is well known to be associated with chronic low-grade inflammation [2], and age-related differences in immune response may influence post-procedural inflammatory markers such as leukocyte count and C-reactive protein. Given that inflammatory markers constituted one of the primary outcomes of the study, further adjustment for age-related inflammatory susceptibility or a sensitivity analysis stratified by age might help clarify whether the observed differences were attributable solely to ablation modality. Intra-procedural cardioversion was performed significantly more frequently in the CB group than in the BiB-PFA group [1]. We would appreciate clarification regarding the reasons for this discrepancy. Electrical cardioversion itself may induce transient myocardial injury or systemic inflammatory responses. Therefore, it is conceivable that the higher frequency of cardioversion in the CB group contributed, at least in part, to the observed biomarker differences. An analysis adjusting for cardioversion or excluding patients who underwent cardioversion might further strengthen the conclusions. Although the study is described as prospective, there was a notable procedural modification within the BiB-PFA group [1]. Specifically, the first 30 patients underwent high-density voltage mapping, whereas the subsequent 20 patients were treated using anatomical reconstruction with the BiB-PFA catheter alone. Such a mid-study change in procedural strategy may introduce heterogeneity that could affect biomarker outcomes, particularly procedural duration, lesion characteristics, and myocardial injury. Further clarification on how this procedural evolution was accounted for in the analysis would be helpful. The clinical interpretation of the higher myocardial biomarker release observed in the BiB-PFA group deserves further discussion [1]. It remains unclear whether the greater elevation in troponin T and creatine kinase directly reflects a larger or more effective ablation lesion. In radiofrequency ablation, myocardial biomarker release has been shown to correlate positively with delivered energy, such as the ablation index [3]. If a similar relationship holds true across different energy sources, one might question whether PFA induces myocardial injury beyond what is necessary for durable pulmonary vein isolation. Conversely, if long-term arrhythmia recurrence rates are comparable between PFA and CB, the clinical necessity of such extensive myocardial injury may be debatable [4]. Unfortunately, arrhythmia recurrence data were not provided in the present study, and future investigations integrating biomarker release with lesion durability and clinical outcomes would be highly informative. The authors have nothing to report. The authors have nothing to report. The authors received no specific funding for this work. The authors declare no conflicts of interest. The authors have nothing to report.