This study used computational modeling to quantify the impact of the proximity of the ventricle (a large structure with high electrical conductivity) to the electrode on the coagulation zone created during radiofrequency (RF) thermocoagulation (RF-TC) in the treatment of periventricular heterotopia-related epilepsy. We built a first model based on full brain inspired by a medical imaging. Once we checked that a limited-domain offer similar electrical performance, we used this latter model to calculate the coagulation zone during bipolar RF-CT (3 W-20 s) with a 0.8 mm diameter electrode and two 2 mm contacts separated by 1.5 mm. Our experience suggest the existence of a peri-electrode gap of 0.2–0.5 mm filled by cerebrospinal fluid, resulting in initial impedances ranging between 300 and 550 Ω, as observed in clinical practice. The existence of this gap provides a protective effect, minimizing thermal damage to the ventricle when the electrode is very close (distances <2.5 mm), while barely distorting the geometry of the coagulation zone. Beyond the clinical consequences of the damaged outer surface area of the ventricle, our results do not show alteration of the coagulation zone due to the proximity of the ventricle.