An implantable medical device (IMD) comprises a transmitting/receiving (T/R) device for transmitting medical data sensed from a patient to, and for receiving control signals from, a medical expert (a human medical professional and/or a computerized expert system) at a remote location; an electronic medical treatment device for treating the patient in response to control signals applied thereto; and a sensor circuit, having a sensor circuit output, for producing sensor circuit output signal(s) representing medical data sensed from the patient. The IMD also includes a logic device (processor) which analyzes the sensor circuit output signal(s) to detect a medical abnormality and, upon detecting an abnormality, either sends a notification signal representing a medical state of said patient to the medical expert at the remote location or sends a local treatment device control signal to the medical treatment device, or does both. The medical expert can transmit an external treatment control signal to the IMD to effect patient treatment, if treatment is warranted. To ensure that the medical expert is authorized to provide such treatment, data which identify one or more authorized medical experts is stored in an IMD memory and compared with identification data transmitted from the putative authorized medical expert along with the external treatment control signal. Only if the identification data received from the putative authorized medical expert matches the pre-stored identification data of an originally authorized medical expert does the IMD effect treatment.