Patent ID: 7684861

Claim:
An implantable medical device, comprising: a sensing circuit adapted to sense an electrogram, the sensing circuit having a set of cutoff frequencies for filtering the sensed electrogram, the set of cutoff frequencies programmed to be a first set of values and a second set of values at different times, the first set of values suitable for far-field electrogram sensing, the second set of values suitable for intracardiac electrogram sensing and different from the first set of values; a pacing circuit; and a processor coupled to the sensing circuit and the pacing circuit, the processor including a cardiac monitor controller that is upgradeable to a pacemaker controller by programming the implantable medical device to configure the implantable medical device from an implantable cardiac monitor to an implantable pacemaker, wherein the implantable medical device is configured to operate as the implantable cardiac monitor and the implantable pacemaker at said different times, the pacing circuit is adapted to be inactive when the implantable medical device is configured to be the implantable cardiac monitor and capable of producing pacing pulses when the implantable medical device is configured to be the implantable pacemaker, and the set of cutoff frequencies of the sensing circuit is programmed to the first set of values while the pacing circuit is inactive and programmed to the second set of values while the pacing circuit is capable of producing pacing pulses.