Abstract: A method and an apparatus for performing implementing external data into an implantable medical device. A first stress test is performed using an external sensor. External data resulting from the initial stress test is acquired. An external data injection process is performed. The external data injection process includes providing the external data to the implantable medical device. A second stress test is performed, the second stress test being substantially similar to the first stress test. Internal data resulting from the second stress test is acquired. Internal data resulting from the second stress test along with the external data resulting from the first stress test, are processed.

Abstract: A method and an apparatus for performing implementing external data into an implantable medical device. A first stress test is performed using an external sensor. External data resulting from the initial stress test is acquired. An external data injection process is performed. The external data injection process includes providing the external data to the implantable medical device. A second stress test is performed, the second stress test being substantially similar to the first stress test. Internal data resulting from the second stress test is acquired. Internal data resulting from the second stress test along with the external data resulting from the first stress test, are processed.

Abstract: A pacemaker capable of automatically adjusting the sensitivity of its sense amplifier to electrical cardiac signals is disclosed. In one embodiment, a pacemaker having a pressure sensor disposed on the distal end of its pacing/sensing lead counts the number of pressure events and electrical events which occur during an autosensitivity timing period. If the number of electrical events exceeds the number of pressure events by more than a predetermined margin, the sense amplifier's sensitivity threshold is decreased. If the number of electrical events does not exceed the number of pressure events by more than the predetermined margin, the sense amplifier's sensitivity threshold is increased. In another embodiment, the pacemaker maintains a running average of the peak voltages of sensed electrical events over a predetermined history period.

Abstract: A method of and apparatus for telemetering analog and digital data transcutaneously between an implantable medical device and an external receiver, such as between an external programmer and an implantable cardiac pacer. A damped carrier at 175 kilohertz is pulse position modulated by digital data. The data, along with synchronization and identification codes, are positioned into predefined ranges within predefined frames as measured by individual time periods. The data is uniquely identified by the position of one or more bursts of the carrier within the predefined range. An automatically initiated hand shake protocol maintains the link over slight variations in programmer head position with an indicator notifying the operator when repositioning is required. Analog data may be transferred in digital form or alternatively transferred using phase modulation of the carrier bursts. A cyclic redundancy code is used for link error detection.

Abstract: A method and apparatus for determination of battery end-of-service in a medical device in which the medical device comprises a cathode limited electrochemical cell having an active metal anode and a manganese dioxide cathode and means for digital telemetry of cell voltage. The sloped, well defined voltage curve of such a cell during cell discharge combined with precise information available through digital telemetry allows for improved determination of battery end-of-service for the medical device.

Abstract: An implantable physiologic device, e.g., a multi-programmable, microprocessor based cardiac pacemaker, is provided with data storage and transmission capabilities for transmitting out certain current operating parameters and sensed events and for storing counted events for transmission of counts, histograms and real-time clock data out on command. The device preferably comprises a rate responsive cardiac pacemaker for providing an optimized pacing rate of stimulation pulses as a function of at least one selected rate control parameter. Each rate control parameter has a value which varies as a function of changes in a patient's physiologic demand and includes a sensor system for sensing the rate control parameter value and for providing a sensor output representative thereof.

Abstract: An automatic capture restoration and threshold-seeking method and apparatus for use with a cardiac pacemaker derives control signals for restoring cardiac capture from a cardiac pressure sensor. The pressure sensor also provides input control signals for a threshold-seeking apparatus. Both pulse width and amplitude thresholds can be changed contemporaneously during both capture restoration and threshold seeking.

Abstract: An implantable medical device for human implant. The device includes a telemetry transmitter and receiver for communicating information from the implanted device to an external programmer or monitor and for receiving commands or other information from an external programmer. The device is provided with one or more sensors and means for monitoring, recording and storing the recordings of physiologic signals after implant. The device is provided with a waveform compression and storage system which stores monitored signals in the form of defined analog voltages maintained within the device, rather than employing more traditional digital storage techniques.

Abstract: A method of and apparatus for telemetering both analog and digital data transcutaneously between an implantable medical device and an external receiver, such as between an external programmer and an implantable cardiac pacer. A damped carrier at 175 kilohertz is pulse position modulated by digital data. The data, along with synchronization and identification codes, are positioned into predefined ranges within predefined frames as measured by individual time periods. The data is uniquely identified by the position of a burst of the carrier within the predefined range. An automatically initiated hand shake protocol maintains the link over slight variations in programmer head position with an indicator notifying the operator when repositioning is required. Analog data may be transferred in digital form or alternatively transferred using phase modulation of the carrier bursts. A cyclic redundancy code is used for link error detection.

Abstract: A rate responsive cardiac pacemaker for providing an optimized pacing rate of stimulation pulses as a function of at least one selected rate control parameter. Each rate control parameter has a value which varies as a function of changes in a patient's physiologic demand and includes a sensor system for sensing the rate control parameter value and for providing a sensor output representative thereof.

Abstract: A pacemaker system includes a dual sensor implantable pacemaker and an external programmer for automatically and simultaneously optimizing and initializing a plurality of pacing parameters. The pacemaker includes means for automatically initializing a sensitivity threshold, pacing pulse width, pacing pulse amplitude, activity threshold, and pressure rate response gain setting.

Abstract: A rate responsive cardiac pacemaker for providing an optimized pacing rate of stimulation pulses as a function of at least one selected rate control parameter. Each rate control parameter has a value which varies as a function of changes in a patient's physiologic demand an includes a sensor system for sensing the rate control parameter value and for providing a sensor output representative thereof. The cardiac pacemaker also includes control circuitry which includes a rate response defining means for deriving desired pacing rates as a function of the sensor output and an achievement monitoring means that has a predetermined achievement criterion, for monitoring the relationship between the derived pacing rates and the achievement criterion over an achievement output. An output circuitry provides optimized pacing rates as a function of the desired pacing rates; and a rate response control means adjusts the rate response defining means accordingly.

Abstract: A rate responsive cardiac pacemaker for providing an optimized pacing rate of stimulation pulses as a function of at least one selected rate control parameter. Each rate control parameter has a value which varies as a function of changes in a patient's physiologic demand and includes a sensor system for sensing the rate control parameter value and for providing a sensor output representative thereof. The cardiac pacemaker also includes control circuitry which includes a rate response defining means for deriving desired pacing rates as a function of the sensor output and an achievement monitoring means that has a predetermined achievement criterion, for monitoring the relationship between the derived pacing rates and the achievement criterion over an optimization period.

Abstract: A rate responsive pacemaker and a pacing method for optimizing the pacing decay curve after a period of increased activity. The pacing method includes the steps of selecting a set of predetermined achievement criteria such as an achievement rate and an achievement time interval. The achievement rate is selected between an upper pacing rate and a first pacing switch rate threshold. The pacing method then determines whether the achievement criterion has been met. If the achievement criterion has been met, then the decay time constant of the decay curve changes from a first value to a second value, as the pacing rate drops below the first pacing switch rate threshold. A second pacing switch rate threshold lower than the first pacing switch rate threshold is then selected, and, if the achievement criteria have been met, then the decay time constant of the decay curve is modified from the second value to a third value, as the pacing rate drops below the second pacing switch rate threshold.

Abstract: A method and apparatus are disclosed for telemetering both analog and digital data from an implantable medical device to an external receiver, such as between an implanted cardiac pacer and its external programming equipment. Analog data is first converted to digital format by an analog-to-digital converter, such that the transmission is digital data. A damped carrier at 175 kilohertz is pulse position modulated by the data. The modulation scheme defines a frame of slightly less than 2 milliseconds. The frame is divided into 64 individual time periods using a crystal clock. The data, along with synchronization and identification codes, are positioned into predefined ranges within each frame as measured by the individual time periods. The data is uniquely identified by the position of a burst of the carrier within the predetermined range.