It is a common practice that an equivalent mathematical model of an implant is used to estimate in vivo power deposition caused by RF-implant interactions. The model is often derived under in vitro conditions. We assess the suitability of test media for RF-induced heating model derivation at 64 MHz. Based on simple generic leaded-implants, our preliminary analysis shows that the test medium specified in ASTM 2182 (εr = 78, σ = 0.47 S/m) may be appropriate for the safety assessment of leaded cardio implants with respect to RF-induced heating. Future analysis shall include implants with diverse topology and increased realism.