Tissue Conductivity Anisotropy is Insufficient to Capture Experimental Lesion Morphology in Cardiac PFA Modelling

Pulsed field ablation (PFA) is a promising treatment for cardiac arrhythmia, but the mechanisms of lesion formation in cardiac tissue remain unclear. Existing computational models typically assume isotropic media and rely on electric field thresholds, which fail to reproduce experimentally observed lesion morphology. We extend our previous work by incorporating cardiac fiber orientation and anisotropic conductivity into a porcine open-chest geometry. Simulations with varying anisotropy ratios showed only minor effects on lesion dimensions, and results did not match experimental data. These findings indicate that anisotropy alone is insufficient to explain lesion geometry in ventricular PFA, and additional mechanisms such as directional electroporation or thermal effects must be considered for accurate modeling.