Parametric analysis of thermal ablation treatment for functional re-entry arrhythmias

Abstract

In this work, test cases are examined about the dynamics of functional re-entry arrhythmias in two dimensions and how it behaves after thermal ablation. The bioheat transfer problem of radiofrequency ablation is given by Pennes’ model. The electrophysiological problem for propagation of action potential in cardiac tissue is simulated with the 3V-SIM model (Fenton-Karma). Functional re-entry arrhythmia is caused by a heterogeneous region in the domain that has different restitution properties. Coupling of the problems is achieved with an Arrhenius’ thermal damage model that considers intermediate damage levels. Numerical experiments are performed for different configurations to analyze the effect of different parameters and dynamical behavior. Re-entry is examined for 4 different vertical positions of a rectangular heterogeneity, varying its length among 3 values. For each case that did exhibited re-entry, 6 different ablation procedures were performed by changing the electrode position and heating time. Each case is investigated to detail the relevant features and interplay between models brought by the coupling, especially regarding the influence of the transition region (sub-lethal damage) over wavebreak, spiral formation, conduction slowdown, effectiveness of the ablation and vulnerability of the resultant domain.