An implantable medical device is provided that comprises data communication means which include means for altering or generating an oscillatory electric field imposed on body tissue surrounding the implantable medical device when the implantable medical device is in its implanted state. In a first embodiment, the means for altering an oscillatory electric field are configured to modulate an impedance of body tissue surrounding the implantable medical device when the implantable medical device is in its implanted state and within an oscillatory electric field. In an alternative embodiment, the means for altering an oscillatory electric field comprise means for generating an oscillatory electric field that is phase-synchronized with an oscillatory electric field imposed on body tissue surrounding the implantable medical device when the implantable medical device is in its implanted state.
