A 3-Dimensional In Silico Test Bed for Radiofrequency Ablation Catheter Design Evaluation and Optimization

Abstract

A 3-Dimensional in Silico Test Bed for Radiofrequency Ablation Catheter Design Evaluation and Optimization Carolyn Teng Atrial fibrillation (AF) is the disordered activation of the atrial myocardium, a major cause of thrombogenesis and stroke. Currently, the most effective minimally traumatic treatment for AF is percutaneous catheter ablation to isolate arrhythmogenic areas from the rest of the atrium. The standard in vitro evaluation of ablation catheters through lesion studies is a resource intensive effort due to ablation substrate tissue variability and visual measurement methods, necessitating large sample sizes and multiple prototype builds. To address this, a computational test bed for ablation catheter evaluation was built in SolidWorks® using morphology and dimensions of the left atrium and adjacent structures. From this geometry, the physical model was built in COMSOL Multiphysics®, where a combination of laminar fluid flow, electrical currents, and bioheat transfer were used to simulate irrigated radiofrequency (RF) tissue ablation. Simulations in simplified 3D geometries led to lesion sizes within reported ranges from an in-vivo ablation study; however, while the ellipsoid morphologies in the full atrial model were consistent with past lesion studies, there were sizeable differences in lesion sizes. Perpendicularly oriented catheter tips were associated with decreases of-91.3% and-70.0% in lesion depth and max diameter, while tangentially oriented catheter tips produced lesions that were off by-28.4% and +7.9% off for max depth and diameter. Preliminary investigation into the causes of the discrepancy were performed for fluid velocity, contact area, and other factors. Guided by the findings of these studies, suggestions for further investigation are provided to aid in root cause determination of this lesion discrepancy, such that the test bed may be verified for use for other ablation catheter evaluations.