Intracardiac electrogram analysis may allow for prediction of lesion transmurality after pulsed field ablation of atria in a porcine model

Background: Pulsed field ablation (PFA) is a novel cardiac ablation modality with an increasing clinical acceptance in treatment of atrial fibrillation due to its clinical efficacy and excellent safety profile. However, intraprocedural guidance for PFA to ensure durable pulmonary vein isolation (PVI) is lacking. Objective: We quantified changes in intracardiac electrograms (iEGMs) following PFA and radiofrequency ablation (RFA) and investigated their applicability for prediction of lesion transmurality. Methods: We induced 38 atrial lesions using PFA or RFA in 5 swine and monitored iEGMs continuously for up to 30 minutes postablation. The most characteristic changes in iEGMs were quantified after the decomposition using discrete wavelet transform, which allowed us to analyze the effects in separate frequency bandwidths. Results: After the ablation, we observed a reduction of bipolar iEGM amplitude (for PFA and RFA) and an increase in unipolar iEGM amplitude (predominantly for PFA). These changes were due to 2 mechanisms with different frequency content. The low-frequency content of unipolar iEGMs (1–16 Hz) further enabled us to discriminate between transmural and nontransmural lesions in the case of PFA. The rate of reduction of initially increased current-of-injury effect reflected in the low-frequency content of unipolar iEGMs within the first few minutes postablation was significantly higher and more pronounced for nontransmural lesions. Conclusion: This study shows that unipolar iEGMs can be used to differentiate between transmural and nontransmural atrial lesions within minutes after PFA in a porcine model, with implications for development of intraprocedural guidance of PFA procedures.