Background and objectives: Pulsed Electric Field (PEF) ablation has been proposed as a non-thermal energy to treat atrial fibrillation (AF) by ablation of ganglionated plexi using the epicardial approach. The electric field distribution at the target site (heart) and its surroundings has not yet been assessed previously, using epicardial ablation technique. Our objective was to develop computational models, incorporating the real anatomy of the heart and the patient's torso, to assess the electric field distribution when applying epicardial monopolar PEF.
Methods: A novel 3D realistic full torso model was built with the multi-electrode ablation device placed on the epicardium and a dispersive pad on the patient's back to evaluate the electric field distribution. The 400 V/cm isoline was used to estimate the 'PEF-zone'. A 3D limited-domain model was also built including only the region of interest around the ablation device to assess its validity in comparison with the full torso model.
Results: The electrical field is mainly limited to the target site (PEF-zone with lengths of 25.79 to 29.00 mm, depths of 5.98-7.02 mm and maximum widths of 8.75-10.57 mm) and is practically negligible in adjacent organs (<30 V/cm and <36 V/cm in oesophagus and lungs, respectively). The electrical currents ranged from 3.67 A to 7.44 A. The 3D limited-domain model provided a similar electric field distribution to those obtained from the 3D full torso models (differences < 0.5 mm in PEF-zone depth).
Conclusions: Computational results suggest that PEF-zone is very focused around the ablation catheter. Limited-domain models offer similar results in terms of PEF-zone size, reducing the complexity of the modelling.
Keywords: Cardiac arrhythmia; Computer modelling; Epicardial ablation; Limited-domain model; Pulsed field ablation; Torso model.
Copyright © 2022. Published by Elsevier B.V.