(A) Assembled phantom with two self-designed holders and three different landmarks. (B) The skull mold was 3D printed to fill in the agar gel mimicking the brain tissue (ε1=76, σ1=0.44S/m) through the hole, enabling the conductive connection between gel inside the skull and outside. The heart mold consisted of two coronal halves attached to create a closed container filled with agar-based solution (ε2=76, σ2=0.65S/m). Once the gel solidified, the semi-solid heart structure was removed and placed on a 3D printed holder inside the phantom (C). The rest of the phantom container was filled with PAA mimicking average tissue (ε3=87, σ3=0.48S/m). A 35 cm epicardial lead (Medtronic CapSure® EPI 4965) connected to a Medtronic Azure™ XT DR MRI SureScan pulse generator was used in the experiments. (D) A fiber optic temperature probe (OSENSA, Vancouver, BC, Canada) was secured at the tip of the lead using thread.