Effect of Anisotropic Electrical Conductivity Induced by Fiber Orientation on Ablation Characteristics of Pulsed Field Ablation in Atrial Fibrillation Treatment: A Computational Study

Abstract

Pulsed field ablation (PFA) is a promising new ablation modality for the treatment of atrial fibrillation (AF); however, the effect of fiber orientation on the ablation characteristics of PFA in AF treatment is still unclear, which is likely an essential factor in influencing the ablation characteristics. This study constructed an anatomy-based left atrium (LA) model incorporating fiber orientation and selected various electrical conductivity and ablation targets to investigate the effect of anisotropic electrical conductivity (AC), compared with isotropic electrical conductivity (IC), on the ablation characteristics of PFA in AF treatment. The results show that the percentage differences in the size of the surface ablation area between AC and IC are greater than 73.71%; the maximum difference in the size of the ablation isosurface between AC and IC at different locations in the atrial wall is 3.65 mm (X-axis), 3.65 mm (Z-axis), and 4.03 mm (X-axis), respectively; and the percentage differences in the size of the ablation volume are greater than 6.9%. Under the condition of the pulse, the amplitude is 1000 V, the total PFA duration is 1 s, and the pulse train interval is 198.4 ms; the differences in the temperature increase between AC and IC in LA are less than 2.46 °C. Hence, this study suggests that in further exploration of the computational study of PFA in AF treatment using the same or similar conditions as those used here (myocardial electrical conductivity, pulse parameters, and electric field intensity damage threshold), to obtain more accurate computational results, it is necessary to adopt AC rather than IC to investigate the size of the surface ablation area, the size of the ablation isosurface, or the size of the ablation volume generated by PFA in LA. Moreover, if only investigating the temperature increase generated by PFA in LA, adopting IC instead of AC for simplifying the model construction process is reasonable.

How intramyocardial fat can alter the electric field distribution during Pulsed Field Ablation (PFA): Qualitative findings from computer modeling

“…This implies a degree of anisotropy of only 11% in terms of electrical conductivity at low frequencies, which probably has a minimal impact on ablation modeling. Differences of around 26% were reported by Gabriel et al [25] at 40-70 Hz in three different directions, which implies an anisotropy ratio of 1.27, and much lower than those assumed by Zang et al [13] (between 1.43 and 6.25) in a computational PFA modeling study, who did find differences in terms of the lesion size induced by PFA between an isotropic and anisotropic model.…”

A New Hope for the Treatment of Atrial Fibrillation: Application of Pulsed-Field Ablation Technology

“…Physical field parameter simulation research is an important stage in the clinical application of new technologies, and reasonable PFA parameters will substantially reduce the cost of clinical research [ 37 , 44 , 74 ]. The researchers obtained a simplified cardiac model from between models of different complexities that can get more accurate simulation results, which provides data support for reducing the complexity of the model in the future.…”

“…The results showed that the difference in surface ablation area between anisotropic and isotropic conductivity was greater than 73.71%, and the percentage difference in ablation volume size was greater than 6.9%. It was shown that in left atrial ablation, anisotropic conductivity can be used for pulsed-field ablation if the same area and depth are considered [ 44 ]. PFA is classified as a non-thermal ablation technique, and the rise in tissue temperature is directly correlated with the heart’s blood flow.…”

A Multiscale Computational Model of Skeletal Muscle Electroporation Validated Using In Situ Porcine Experiments

“…Another increasingly important application of electroporation in biomedicine is treatment of cardiac arrhythmias, particularly of atrial fibrillation, by ablation of pulmonary vein tissue using irreversible electroporation [10], [15]- [18]. The specific structure of skeletal and cardiac muscles dictates an anisotropic electrical conductivity, leading to a fibre-orientation dependent electric field distribution upon pulse application [19]- [21]. The electrical conductivity of skeletal muscle in the direction of its fibres was found to be higher than the electrical conductivity in the direction perpendicular to the fibres [22]- [27].…”