Computer modeling to study the dynamic response of the temperature control loop in RF cardiac ablation

Abstract

Radiofrequency (RF) ablation is currently used to treat some types of cardiac arrhythmias such as Atrial Fibrillation (AF). Currently, the most used protocol type of delivering RF energy is controlled-temperature. The commercially available RF generators employ a PI controller. This controller has fixed parameters denominated Kp and Ki. There are no experimental or theoretical studies on the behavior of this controller against to variations in electrical and thermal characteristics of the tissue, electrode design, tissue penetration, and circulating blood flow. We built a theoretical 2D model which we solved using the Finite Element Method (FEM). We used COMSOL Multiphysics for implementing thermalelectric coupling problem and MATLAB for implementing the temperature control loop. The results suggest that the values of Kp and Ki do not affect generally the dynamic response of the controller. However, for some values of tissue characteristics, oscillations in target temperature were observed. © 2010 International Federation for Medical and Biological Engineering.