Electroacoustic tomography guided nanosecond pulsed field ablation: a simulation study

Pulsed field ablation (PFA) is a promising non-thermal method for treatment of atrial fibrillation that works by inducing irreversible electroporation in cardiac tissue. The procedure is designed to avoid heat damage. However, longer (microsecond) pulse durations can still generate thermal effects. Nanosecond pulses can deliver the necessary electric field much faster, reducing the risk of heating and potentially improving spatial precision and treatment safety. Currently, PFA is an open loop process which does not allow for real time lesion visualization. The lack of real time visualization significantly limits the capabilities of this procedure, leading to incomplete electroporation, and an increase in the likelihood of arrhythmia and the need for repeat procedures. This work presents an initial simulation framework which is aimed at closing the loop and providing real time feedback. The electric field distribution was simulated with a simplified circular catheter with alternating current and ground segments in COMSOL. Biphasic +700 V/ -700V pulses of 100 ns were applied to a homogeneous cardiac tissue domain. Electric energy density was exported at the midpoint of the active pulse window to be imported into a 3D k-Wave acoustic model. The resulting pressure fields were predicted by numerically modeling an electro-acoustic tomography (EAT) process. The time reversal reconstructions generated from these simulations offer a first step towards demonstrating the feasibility of detecting PFA induced lesions. These results are an initial step towards developing a closed-loop PFA system that can deliver nanosecond pulses while simultaneously monitoring lesions, with the overarching goal of making ablation procedures more precise and consistent.