BACKGROUND Pulsed field ablation (PFA) is a novel nonthermal cardiac ablation technology based on irreversible electroporation (IRE). While areas of IRE lead to durable lesions, the surrounding regions, where reversible electroporation occurs, recover. The behavior of local electrograms in areas of different electroporation levels remains unknown. The goal of this study is to characterize electrogram dynamics after PFA in IRE and reversible electroporation areas. METHODS A total of 6 domestic swine were used. PFA was applied in the epicardium of the right and left ventricles using a focal monopolar catheter. Additional radiofrequency ablations were performed. Epicardial unipolar electrograms were acquired at baseline and for 60 minutes post PFA/radiofrequency ablation using a high-density electrode matrix attached to the epicardium. Electrogram dynamics were analyzed in areas corresponding to different levels of electroporation. Acute lesion formation was assessed after 3 to 5 hours by triphenyl tetrazolium chloride staining. RESULTS Electrogram analysis demonstrated a clear association between electrogram changes and the level of electroporation. Immediately after PFA, electrograms displayed the following: a significant decrease in R/S-wave amplitude; a large elevation of the ST-segment; and a large decrease in their |(dV/dt)|max. Marked changes in electrograms were observed beyond the lesion area. Thereafter, a gradual recovery was observed. The evolution of all the electrogram parameters throughout the 60 minutes after PFA was significantly different (P<0.05) between the IRE and reversible electroporation areas. Acute lesion staining showed significantly larger depth for PFA lesions compared with radiofrequency ablation. CONCLUSIONS This study shows that unipolar electrograms can differentiate between reversible electroporation and IRE areas during the first 30 minutes post ablation. Differences after the first 30 minutes are less evident. Our findings could result useful for immediate lesion assessment after PFA and warrant further investigation.

中文翻译：

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PFA 期间高密度单极心外膜电图的动态。

背景技术脉冲场消融（PFA）是一种基于不可逆电穿孔（IRE）的新型非热心脏消融技术。虽然 IRE 区域会导致持久损伤，但发生可逆电穿孔的周围区域会恢复。不同电穿孔水平区域的局部电描记图的行为仍然未知。本研究的目的是表征 PFA 后 IRE 和可逆电穿孔区域的电描记图动力学特征。方法选用家猪6头。使用局部单极导管将 PFA 应用于右心室和左心室的心外膜。进行了额外的射频消融。使用附着在心外膜上的高密度电极矩阵在基线和 PFA/射频消融后 60 分钟内采集心外膜单极电图。在对应于不同电穿孔水平的区域中分析电描记图动力学。3至5小时后通过氯化三苯基四唑染色评估急性损伤形成。结果 电描记图分析表明电描记图变化与电穿孔水平之间存在明显关联。PFA 后，电图立即显示以下内容：R/S 波振幅显着降低；ST 段大幅抬高；并且|(dV/dt)|max 大幅下降。在病变区域之外观察到电图的显着变化。此后，观察到逐渐恢复。PFA 后 60 分钟内所有电描记图参数的演变在 IRE 和可逆电穿孔区域之间显着不同 (P<0.05)。与射频消融相比，急性病变染色显示 PFA 病变的深度明显更大。结论 这项研究表明，单极电描记图可以在消融后的前 30 分钟内区分可逆电穿孔和 IRE 区域。前 30 分钟后差异就不那么明显了。我们的研究结果可能有助于 PFA 后立即进行病变评估，并值得进一步调查。