The system includes a sensor assembly comprising a body implantable physiological sensor for controlling a body implantable action device operable to act upon the body in response to changes in a physiological parameter sensed by the sensor. The body implantable action device can be a heart pacing device, a drug infusion pump, or other device which acts upon a human body. The sensor assembly includes a transmitter for transmitting coded signals to the action device which has programming circuitry for deciphering the signals received from the sensor assembly generated by the sensor which is in a location away from the location of the action device. Once these signals have been deciphered, the programming circuitry can adjust the output from the action device, such as the rate and A-V delay of pacing pulses from the pacing circuitry. In one embodiment, the transmitter is a radio transmitter and the programming code transmitted therefrom is picked up by an output terminal, such as a distal electrode of a pacing lead, which acts as a pickup antenna.