Abstract: A system for internally sensing the cardiac electrogram in a patient with a cardiac pacemaker is disclosed comprising an implanted electrode that, in combination with the metallic case of the pacemaker which acts as an indifferent electrode, senses cardiac electrical signals and provides them as an input to the pacer electronics. The sensing electrode is appropriately spaced from the pacing electrode and positioned so that cross coupling is minimized to permit sensing of the cardiac electrogram without undue interference from the pacing stimulus and after potentials, and so that the pickup of both R- and P-waves is optimized. The sensed signals may be used to control atrial, ventricular or multichamber demand pacemakers and/or may be telemetered out of the patient for pickup and analysis by external equipment. A flat plate and a preferred cylindrical ring form of electrode are described.

Abstract: A complete system for telemetering and monitoring the functioning of an implanted pacemaker as well as controlling the testing of the functions from a remotely located central facility is disclosed specifically comprising the provision of capabilities for directly and simultaneously transmitting from the pacer, electrical signals indicative of multiple pacer functions such as pacer rate, cell voltage, refractory period, heart rate with pacer inhibited, R-wave level and sensing margin, sensing circuit and other component failure, cardiac electrode, lead break, and hermetic integrity. The indicative signals are picked up at the patient's location for local analysis and/or telephonically communicated to a remote central monitoring station. The central station may control testing of the pacemaker functions by transmitting command signals back telephonically for coupling through cooperating external and implanted inductances or mangetically controlled switches to the implanted pacer circuitry.

Abstract: A complete system for telemetering and monitoring the functioning of an implanted pacemaker as well as controlling the testing of the functions from a remotely located central facility is disclosed specifically comprising the provision of capabilities for directly and simultaneously transmitting from the pacer, electrical signals indicative of multiple pacer functions, such as, pacer rate, cell voltage, refractory period, heart rate with pacer inhibited, R-wave level and sensing margin, sensing circuit and other component failure, cardiac electrode lead break, and hermetic integrity. The indicative signals are picked up at the patient's location for local analysis and/or telephonically communicated to a remote central monitoring station. The central station may control testing of the pacemaker functions by transmitting command signals back telephonically for coupling through cooperating external and implanted inductances or magnetically controlled switches to the implanted pacer circuitry.