Castellvi Quim, Ivorra Antoni
Department of Engineering, Universitat Pompeu Fabra, Barcelona, Spain.
Int J Numer Method Biomed Eng. 2025 Aug;41(8):e70077. doi: 10.1002/cnm.70077.
Pulsed Field Ablation (PFA) is an electroporation-based treatment modality to perform cardiac tissue ablations. Heart parenchyma is mainly constituted by elongated myocytes organized in fibers. This anisotropic morphology results in a preferential pathway for the electric current to flow along. Assuming conventional PFA modeling approaches in which lesions form where the electric field surpasses a threshold, such conductance anisotropy would result in relatively wide and shallow lesion morphologies when PFA applications are delivered with a focal monopolar catheter. Contrary to that, some recent preclinical data present narrow and deep elongated lesions. This study presents a multiscale simulation approach able to estimate electroporation treatment outcomes when applied in a highly anisotropic tissue such as the myocardium. In this work, a microscopic model was first implemented mimicking the conformation of the cardiac tissue. Longitudinal and transversal electric fields at different frequencies and magnitudes were applied to characterize the expected anisotropic behavior at the tissue level in terms of electric conductivity and expected membrane disruption due to electroporation. Second, the microscopic characterization was integrated into a macroscopic model of a focal ablation catheter in contact with the myocardial tissue to simulate the delivery of monopolar PFA treatments. The microscopic simulations results show that when low electric field magnitudes are applied, the induced membrane disruptions predominantly appear in fibers parallel to the electric field. However, at higher field magnitudes, a demarcated superior sensitivity is observed in perpendicular orientation. The integration of these anisotropic properties into the macroscopic model predicts width/depth ratios of 1.2 compared to the ratios of about 2 predicted with conventional modeling. In this work, the presented multiscale model and approach can predict relatively narrow and deep lesions, as observed preclinically.
脉冲场消融（PFA）是一种基于电穿孔的心脏组织消融治疗方式。心脏实质主要由排列成纤维状的细长心肌细胞构成。这种各向异性形态导致电流存在优先流动路径。假设采用传统的PFA建模方法，即电场超过阈值的地方形成损伤，那么当使用聚焦单极导管进行PFA治疗时，这种电导各向异性会导致损伤形态相对宽而浅。与此相反，一些近期的临床前数据显示出狭窄且深的细长损伤。本研究提出了一种多尺度模拟方法，能够估计在高度各向异性组织（如心肌）中应用电穿孔治疗的结果。在这项工作中，首先构建了一个微观模型来模拟心脏组织的构象。施加不同频率和幅度的纵向和横向电场，以从电导率和电穿孔导致的预期膜破坏方面表征组织水平上预期的各向异性行为。其次，将微观表征整合到与心肌组织接触的聚焦消融导管的宏观模型中，以模拟单极PFA治疗的实施。微观模拟结果表明，当施加低电场幅度时，诱导的膜破坏主要出现在与电场平行的纤维中。然而，在较高场强下，在垂直方向观察到明显更高的敏感性。将这些各向异性特性整合到宏观模型中预测的宽度/深度比为1.2，而传统建模预测的比值约为2。在这项工作中，所提出的多尺度模型和方法能够预测出如临床前观察到的相对狭窄且深的损伤。
