An implantable medical device includes an actuator and/or sensor portion to be fixed to bodily tissue by means of a fixation mechanism, to act on the tissue and/or to detect a signal from the tissue, wherein at least one detector element, preferably a plurality of detector elements, adapted for detecting the close proximity of bodily tissue, is arranged on the actuator and/or sensor portion of the device, and an output of the or each detector element being connected or connectable to a detection signal evaluation unit for deriving a fixation state verification from detection signals provided by the or each detector element.
