Abstract: A pacemaker contains at least one power-consuming component, such as a sensor with associated electronic circuitry for controlling the pacemaker function or a heart signal detector, and an electrode system for emitting heart stimulation pulses. The power-consuming component is disenabled prior to implantation of the pacemaker. Circuitry is provided for enabling the power-consuming component which is responsive to an event occurring substantially simultaneously with pacemaker implantation in the patient. Such circuitry may include a device for measuring the electrode impedance so as to enable the power-consuming component in response to the measured impedance value. The circuitry for enabling the power-consuming component can alternatively includes internal telemetry equipment in the pacemaker and external telemetry equipment for communications between the telemetry equipments.

Abstract: A device for reducing power consumption in medical electrical equipment, implantable in the human body, having a sensor, which includes a sensor element and sensor electronic circuitry for sensing a parameter relevant to control of the equipment's in vivo operation, also has a comparator which compares the sensor element's output signal to a predesignated threshold value and switches the sensor electronic circuitry from a passive mode with low power consumption to an active mode with heavier power consumption or vice-versa, depending on the magnitude of the sensor element's signal in relation to the threshold value.