Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
OPTIMIZATION OF THERMAL ABLATION FOR FUNCTIONAL RE-ENTRY ARRHYTHMIAS
Submission Author:
Eber Dantas de Sá Paiva , RJ , Brazil
Co-Authors:
Eber Dantas de Sá Paiva, Helcio Orlande, George Dulikravich
Presenter: Eber Dantas de Sá Paiva
doi://10.26678/ABCM.ENCIT2022.CIT22-0471
Abstract
Cardiac arrhythmias are a global health problem associated with various heart conditions and responsible for a significant number of deaths related to sudden cardiac arrest. Thermal ablation is the most common treatment in correcting anomalous heartbeats. However, there are still several limitations to the procedure and varying degrees of success are noticed depending on the type of arrhythmia; for example, in some cases multiple repeated procedures are usually required to achieve stabilization. For the case of rotor-driven functional re-entry arrhythmias, natural heterogeneities of the cardiac tissue cause complex phenomena, as generation of spiral/scroll waves for the electrophysiological signal and dangerous wave break dynamics, which may cause sustained fibrillation. This works analyzes the optimization of thermal ablation procedures for functional re-entry arrhythmias, considering the optimal selection for the position of a radiofrequency electrode. An idealized two-dimensional rectangular region of the cardiac muscle is examined for various positions and sizes of a rectangular heterogeneous tissue that induces re-entry. A radiofrequency electrode is considered as being introduced in the endocardium side, heating the tissue. A two-dimensional bioheat transfer problem was solved with an energy generation term that results from the radiofrequency problem. Thermal damage was given by the Arrhenius´ model and was used to modify electrophysiology parameters in a spatially continuous fashion. Besides a region of acute lesion, this introduces zones of intermediary damage levels. Then, the Fenton-Karma model was used in this work to simulate the electrophysiology dynamics. The optimization problem is structured according to the electrode position for thermal ablation, aiming at minimizing an objective function that reflects the transmission of electrophysiological signals in undesired directions. A Differential Evolution algorithm was used to solve the optimization problem in different conditions of functional re-entry. The results reveal interesting features for the choice of objective function, especially in determining the quality of solution and how the interplay between the chosen models affect the methodology.
Keywords
Rotor-driven Arrhythmia, Functional Re-entry, thermal ablation, Differential Evolution Optimization, Thermal damage, Cardiac Muscle Electrophysiology
