Computational Assessment of Electrical and Thermal Effects of Epicardial Pulsed Field Ablation Adjacent to Stented Arteries

Figures

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  Figure 1. Physical setup during epicardial pulsed field ablation (PFA). (A) The Finger device (AtriAN Medical, Galway, Ireland) is placed on the left atrium epicardial surface with the left circumflex coronary artery (LCx) situated just below the ablation point. (B) The simulated worst case corresponded with the one in which a metal stent was placed inside the LCx just beneath the electrodes.

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  Figure 2. Geometry of the computational models with the LCx in a parallel (A) and perpendicular (B) orientation with respect to the catheter (X = 80 mm, Y = 40 mm, Z1 = 40 mm, Z2 = 2.7 mm, Z3 = 4.75 mm). The stent was displaced with an offset distance (d) of 3 mm at each step from its initial position directly beneath the electrodes to the left side of the LCx. (C) Detail of the epicardial PFA catheter: the four yellow rectangles represent the metal electrodes, each featuring central lumen (shown in blue) through which saline is infused.

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  Figure 3. Physics-optimized meshes used to solve the fluid dynamics problem and the coupled electric–thermal problem. (A) Meshes employed for the fluid dynamics simulations for the LCx artery in parallel and perpendicular orientations. (B) Meshes used to solve the coupled electric–thermal problem for both LCx orientations. Due to the very thin stent wall, local mesh refinements were required in and around the stent region, particularly for the mesh used to solve the intraluminal flow dynamics. Detailed views of these refinements are shown in the magnified insects highlighted by the black circles.

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  Figure 4. Distribution of the electric field ((A): front view—XZ plane; (B): top view—XY plane) for the three scenarios considered (no artery, artery, and stented artery) using 1000 V pulses with the artery positioned parallel and perpendicular to the catheter. The black contour line represents the region where the electric field is ≥1000 V/cm, corresponding to the PFA-induced lethal threshold.

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  Figure 5. Volume of fat, myocardium and the artery wall within the region where the electric field is ≥1000 V/cm (the threshold for the PFA-induced lethal threshold) for both the parallel (A) and the perpendicular (B) artery orientation. All three scenarios studied were included: no artery, artery, and stented artery.

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  Figure 6. Detailed front (XZ plane) and side (YZ plane) views of the electric field distribution with the artery oriented parallel (A) and perpendicular (B) to the catheter, in both non-stented and stented conditions, using 1000 V pulses. The black contour line delineates the region where the electric field is ≥1000 V/cm, corresponding to the PFA-lethal threshold.

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  Figure 7. Volume of artery wall affected by PFA with the artery oriented parallel (A) and perpendicular (B) to the catheter.

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  Figure 8. Maximum temperature evolution for the three tested scenarios (no artery, artery and stented artery) with the artery in parallel and perpendicular positions relative to the catheter. Simulations were conducted using applied voltages of 1000, 2000 and 2500 V, measured after the 60 s PFA procedure followed by a 90 s post-latency period. Thermal damage starts with temperatures greater than 50 °C (yellow dashed line).

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  Figure 9. Temperature distribution at the end of PFA using 2500 V pulses for the different scenarios (no artery, artery and stented artery) studied with the artery placed parallel and perpendicular to the catheter. Panels (A) and (B) show the front (XZ plane) and the top (XY plane) views respectively. The solid black line represents the thermal damage contour Ω = 1.

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  Figure 10. Temporal evolution of the thermally damaged fat volume, accounting for a 90 s latency period following the 60 s PFA application using 2500 V, for both artery orientations: parallel (A) and perpendicular (B) relative to the catheter. Only damage within the fat tissue is shown, as no thermally induced cell death was detected in other tissues (myocardium or arterial wall) under the evaluated conditions.

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  Figure 11. Detail of front (XZ plane) and top (XY plane) views of the fat volume thermally damaged just after PFA (in light green color) and after the latency period (in red color) for the case of 2500 V pulses with a stented artery in parallel (A) and perpendicular (B) positions with respect to the catheter.