This work presents an analysis of the interaction of the electromagnetic field generated by wireless communication systems on Implantable Medical Devices (IMDs) via a simplified model that provides a first-order approximation and via high accuracy full-wave simulation that takes into account the details of the human body holding the implant, the source of electromagnetic field, and the Implantable Medical Device (IMD) geometry and materials. Our results indicate that cellular communication devices, both Base Transceiver Station (BTS) and User Equipment (UE) do not exceed the susceptibility requirement specified for IMDs, while walkie-talkie, even when used according to common manufacturer recommendations, generate a field significantly above this limit.