Worldwide, a significant number of deaths due to heart problems is caused by ventricular arrhythmias, particularly in patients with a history of previous myocardial infarction. Cardiac arrhythmia is the clinical condition of anomalous heartbeat. Thermal ablation is a common treatment of arrhythmias nowadays. However, some problems with this kind of treatment still remain, such as persistent atrial fibrillation in some patients even after 3 to 5 procedures. Among the diverse types of arrhythmias, the rotor-driven functional reentry exhibits quite involved phenomena, like spiral/scroll wave generation and dangerous wave break dynamics, which may cause sustained fibrillation. In this work, the thermal ablation treatment for such kind of arrhythmia was numerically examined by considering an idealized rectangular region of the cardiac muscle. The region of interest was heated by a radiofrequency electrode positioned in the endocardium. A twodimensional bioheat transfer problem was solved with the energy generation term that resulted from the radiofrequency problem, in order to compute the thermal damage in the muscle tissue that was given by Arrhenius' model. Thermally damaged tissues were treated as unexcitable for the electrophysiology Fenton-Karma model used in this work. A parametric analysis was performed to address the sensitivity of the thermal treatment with respect to different input parameters, including the dimensions and location of the heterogeneous muscle region that originates the arrhythmia, location of the electrode and heating time.