TPI Function in Pulsed Field Ablation for Atrial Fibrillation: Hemolysis Control and Organ Protection

In pulsed field ablation (PFA), adequate catheter-tissue contact is crucial as it can effectively reduce the occurrence of hemolysis. Activation of the tissue proximity-indicating (TPI) function ensures effective catheter-tissue apposition. However, to date, no relevant clinical studies have been reported on the correlation between TPI function activation and hemolysis during PFA for atrial fibrillation (AF).

To investigate in depth the correlation between the "TPI" function of catheters and postoperative hemolysis following pulsed field ablation (PFA) for atrial fibrillation (AF) from hematological and pathological perspectives.

By applying PFA treatment in both TPI-ON and TPI-OFF modes to isolated porcine atrial myocardial tissue and in situ atrial myocardium from six pigs, the effects on hemolysis were observed under these two scenarios.

In vitro, plasma free hemoglobin (fHb) increased with the number of applications and was lower with TPI-ON than with TPI-OFF at matched application numbers (p < 0.05). In vivo, both groups achieved transmural lesions with comparable lesion depth. Mean fHb values at 5 and 30 min were numerically lower with TPI-ON, but the group-by-time interaction was not significant (p = 0.153). CK and CK-MB increased transiently within 24 h, whereas urea and creatinine showed no consistent between-group pattern; none of the four biochemical group-by-time interactions remained significant after Holm correction. Renal histology showed no irreversible parenchymal injury in either group.

In this preclinical model, use of the impedance-based TPI function was associated with lower post-PFA hemolysis while preserving acute transmural lesion formation. These findings support further validation of TPI-guided catheter positioning in clinical studies.