A computational model of open‐irrigated radiofrequency catheter ablation accounting for mechanical properties of the cardiac tissue

Abstract

Radiofrequency catheter ablation (RFCA) is an effective treatment for cardiac arrhythmias. Although generally safe, it is not completely exempt from the risk of complications. The great flexibility of computational models can be a major asset in optimizing interventional strategies, if they can produce sufficiently precise estimations of the generated lesion for a given ablation protocol. This requires an accurate description of the catheter tip and the cardiac tissue. In particular, the deformation of the tissue under the catheter pressure during the ablation is an important aspect that is overlooked in the existing literature, that resorts to a sharp insertion of the catheter into an undeformed geometry. As the lesion size depends on the power dissipated in the tissue, and the latter depends on the percentage of the electrode surface in contact with the tissue itself, the sharp insertion geometry has the tendency to overestimate the lesion obtained, especially when a larger force is applied to the catheter. In this paper we introduce a full 3D computational model that takes into account the tissue elasticity, and is able to capture the tissue deformation and realistic power dissipation in the tissue. Numerical results in FEniCS-HPC are provided to validate the model against experimental data, and to compare the lesions obtained with the new model and with the classical ones featuring a sharp electrode insertion in the tissue.

Tissue Drives Lesion: Computational Evidence of Interspecies Variability in Cardiac Radiofrequency Ablation

“…Within the blood compartment, the catheter is placed perpendicularly to the tissue at the middle of the box. We consider a 6-hole electrode with a hemispherical tip and a thermistor inspired by RFA catheters commonly used in clinics, as described in [5]. Figure 1 shows a sample computational geometry for a tissue thickness of H = 20 mm.…”

“…Due to the contact with the catheter, the tissue undergoes a mechanical deformation. The vertical deformation is described in [5] and is formulated as…”

“…All the remaining surfaces are considered electrically insulated. More details on the computational model can be found in [5].…”

“…Typically, ablation protocols are designed and tested using in-vitro, ex-vivo and in-vivo experiments on animals. Porcine cardiac tissue is commonly used in the experiments to assess the efficacy and the safety of the RFA treatment [1,5]. However, the biophysical, mechanical and physiological properties of the porcine cardiac tissue differ from the corresponding human ones [6], thus a direct translation of the experimental results to clinical practice can lead to insufficient treatment or potential life-threatening complications.…”

“…In this study, we investigate the interspecies variability in the RFA treatment using a recently developed computational model [5] which includes the mechanical properties of the tissue. We simulate a commonly used ablation protocol on cardiac tissue of two species: porcine and human.…”