Abstract: An apparatus and method for communicating acoustic telemetry data produced by an implantable medical device over a communication channel includes a signal generator, a modulator, and an acoustic transmitter each provided in the implantable medical device. The modulator modulates a carrier signal with an information signal representative of information acquired or produced by the implantable medical device so as to produce a modulated information signal. The modulated information signal may have a frequency content that is readily accommodated by a public exchange communication channel. The transmitter transmits the modulated information signal as an acoustic information signal in a form communicable over the communication channel. The acoustic information signal may constitute telephonic tones which are directly communicable over a conventional telephone connection.

Abstract: An implantable medical device which preferably has a segmented looping memory for storing triggered physiologic events also has autotriggers to record the ECGs and any other relevant physiologic signals occurring during triggering events. The problem is that in the far field R-wave sensing is difficult because of noise. Denial and extensible accommodation periods are introduced into the R-wave sensing registration for triggering data storage. If the event is sensed during an accommodation period the sense will not add an R-wave sense to the trigger's count of R-waves. It may cause resetting of the trigger count in some circumstnaces. Typical triggering events may include arrhythmia's and syncopal events. Preferably the device can function without a microprocessor. An outside device or other patient activated manual trigger may be included. Auto triggers and manually set triggers may be of different sizes. Electrode spacing can be critical. Additional sensors may be provided to the device.

Abstract: An object management system is providing for managing, cataloging, and discovering various potentially reusable code and data components that exist within an Information Technology (IT) platform, and which each have well-defined interfaces with other components. For each of these re-usable code and data components, an associated software object called an “asset element” is created that describes the associated component. Relationships are created between various asset elements to represent the relationships existing between the software components. Other software objects called “locator elements” are created that each describes an application concept or sub-concept. This application concept or sub-concept is associated with a problem solved by the code and data components within the IT platform. Relationships are created between the various locator elements to correlate the concepts and sub-concepts to software constructs represented by asset elements.

Abstract: A body implantable pressure sensor attached to an endocardial lead for implantation in a heart chamber or cardiac blood vessel for sensing blood pressure and providing blood pressure signals to an implanted or external hemodynamic monitor and/or therapy delivery device and method of fabrication thereof. A pressure sensor module is formed of an elongated receptacle having an elongated receptacle cavity for receiving a calibrated, micro-machined pressure transducer having a pressure responsive element. The receptacle cavity is covered by a diaphragm disposed alongside the lead body and in parallel with the lead axis. The receptacle cavity is filled with a incompressible oil for transferring pressure forces that are applied to the diaphragm to the pressure transducer. The oil is introduced through a fill port, and the fill port is sealed after the oil is introduced to prevent leakage of the oil from the receptacle cavity and to complete the hermetic sealing of the receptacle cavity.

Abstract: In a pacemaker, a method and apparatus for providing rate response in proportion to the patient's metabolic demand for cardiac output as determined in response to the patient's breathing rate or respiratory minute ventilation or contraction strength, optionally augmented by the patient's activity level. An implantable pulse generator (IPG) has one or more pacing leads having a proximal end coupled to the IPG and a distal end in contact with a patient's heart. A pressure wave transducer mounted in the IPG in relation to the proximal end of the pacing lead senses pressure waves transmitted from the distal end of the pacing lead to the proximal end thereof. The pressure waves originate from disturbances imparted to the lead by heart contractions and breathing. A further isolated, reference sensor is also incorporated into the IPG in a similar fashion. An activity signal processor is coupled to the pressure wave or reference sensor for providing a patient activity physiologic signal.

Abstract: A method and apparatus for detecting an RF signal transmitted between an implantable medical device (IMD) and an external medical device programmer in a telemetry session and discriminating the telemetry transmitted RF signal from transient and steady state noise corrupting it. The external programmer includes a programmer telemetry antenna tuned circuit adapted to be driven into oscillation to generate tuned circuit output signals in response to telemetry uplink transmissions of telemetry uplink signals from the IMD, wherein the tuned circuit output signals can exhibit noise artifacts due to contamination by electrical noise. An RF telemetry receiver section detects and demodulates the telemetry uplink signals from the tuned circuit output signals and provides a demodulated uplink signal having a demodulated uplink signal amplitude that varies with time as a function of telemetry uplink signal amplitudes and noise artifacts.

Abstract: An implantable medical device determines activity levels and Heart Rate and from a combination of these produces a value for a heart rate activity coefficient (HRAC). This value has significant diagnostic and patient tracking value. Methods and apparatus for determining this HRAC value are described. This enables physician review of patient cardiac status. Additional physiologic data can be recorded along with the HRAC data if desired, and this too, as well as the HRAC data alone, may be reported out from the implanted device to a medical communications system for alarm purposes, titrating drugs/therapies or other monitoring tasks. Further, substitutes for heart rate measurements and activity measurements are described which can be used to augment or substitute for heart rate measurements and activity measurements.

Abstract: A control system and interface is provided for controlling the transmission of address and data signals via independently operative bi-directional address and data interfaces, respectively, within a data processing system. The system allows address signals to be transferred via the address interface either before, or after, associated data signals are transferred. The address interface operates at a rate which is independent of the rate achieved on the data interface. Address signals transferred on the address interface are stored in one of a plurality of address storage devices depending on request type. A routing circuit associates later-provided data signals with the address storage device storing the associated address signals, and a correlation circuit allows the address storage device to record the data transfer with the associated address signals. According to one embodiment, the correlation is performed using a pointer indicative of a storage location temporarily storing the data signals.

Abstract: An implantable medical device for treatment of cardiovascular disorders by stimulating a selective nerve, the device including an implantable pulse generator, an implantable electrode body and a reservoir. The electrode body includes an electrode electrically connected to the pulse generator. Further, the electrode body is configured to sustain long-term contact between the electrode and the nerve. The reservoir maintains a nerve stimulating drug, such as a veratrum alkaloid, and defines a delivery surface through which the drug is released from the reservoir. Finally, the reservoir is operatively associated with the electrode body to deliver the nerve stimulating drug directly to the nerve. During use, the electrode and the delivered drug stimulate the nerve to effect control over the cardiovascular system of the patient.

Abstract: An apparatus and method for obtaining pressure data using a body implantable pressure sensor includes a measurement capacitor which is responsive to pressure changes of a body fluid. Non-constant, multiple current source charging of the measurement capacitor provides for a significant increase in sensitivity to conditions of pressure of a body fluid. Pressure data is obtained by charging the measurement capacitor at a first charge rate during a first charge period of an integration cycle and, during a second charge period of the integration cycle, charging the measurement capacitor at a second charge rate. The first charge rate is preferably greater than the second charge rate. The duration of the first and second charge periods may be varied. A signal indicative of a pressure change of a body fluid imparted to the measurement capacitor is produced by the pressure sensor. The signal may be a signal indicative of a change in a time of integration.

Abstract: An AV search method and apparatus is taught with some variation. It allows a pacemaker to find the appropriate AV interval so as to avoid pacing in the ventricle when it is not necessary, even if there is intermittent AV conduction in the patient. Also, there is an adaptive PVARP method and apparatus that allows the PVARP and AV interval to be adjusted together automatically.

Abstract: A system and method for determining a patient's cardiac output in a non-invasive manner and transmitting cardiac output data to a remote host processor, a communications system, or a local output device is disclosed. A non-invasive cardiac monitoring approach utilizes an implantable medical device coupled to an oxygen sensor. The oxygen sensor provides venous oxygen saturation data to the implantable medical device. An oxygen consumption unit produces oxygen consumption data using air exhaled by a patient. A processing unit calculates a cardiac output result in real-time using the venous oxygen saturation data, the oxygen consumption data, and arterial oxygen saturation data assumed to be about 100% or acquired using a sensor external to the patient. The implantable medical device may transmit the venous oxygen saturation data to the processing unit using electromagnetic signals or acoustic signals.

Abstract: An implantable medical device monitoring method and system monitors chronic data representative of at least one physiological parameter. The chronic data is monitored to detect changes in state of the at least one physiological parameter. Data associated with detected changes in state is stored within the implantable medical device. The detection of changes in state of the at least one physiological parameter is performed by establishing a baseline (e.g., a center reference line and upper and lower control limits), and then determining if the chronic data being monitored satisfies predetermined conditions (e.g., conditions based on the center reference line and the upper and lower control limits) indicative of a change in state of the at least one physiological parameter. The data stored in memory associated with the detected change in state of the at least one physiological parameter may, for example, include data representative of the center reference line and/or upper and lower control limits.

Abstract: An automatic, body-implantable medical device having at least two modes of operation is disclosed. The device is provided with circuitry for automatically detecting when the device has been implanted in a patient, so that the device can automatically switch from a first mode to a second mode of operation upon implantation. In one embodiment, the first mode is a power conserving mode in which one or more non-essential sub-systems of the device are disabled. Prior to detection of implant, at least two conditions of the device known to reflect whether the device has been implanted are monitored. After implant has been detected, situations in which power to the device is disrupted and then restored will cause the device to enter a predefined "power-on-reset" mode of operation. Prior to detection of implant, however, such conditions do not result in the device entering the power-on-reset mode, or this mode is reset.

Abstract: A barometric pressure sensor for deriving reference pressure data for use in combination with absolute pressure data derived by an implantable medical device (IMD) is disclosed. The barometric pressure sensor is located in a sensing module adapted to be located with the patient's body having a module housing enclosing an air chamber which encloses the barometric pressure sensor. An air vent extends through the module housing for venting the air chamber to atmospheric pressure outside the module housing. A protective vent cover extends across the air vent formed of a material capable of air passage and capable of inhibiting passage of moisture, liquids, and particulate contaminants through the air vent and into the air chamber. In one embodiment, the sensing module is adapted to be worn or carried by the patient and includes operating circuitry and a power supply for powering the barometric pressure sensor and periodically storing sensed atmospheric pressure values as reference pressure data.

Abstract: In determining whether a patient has ischemia or other conditions discernible in the variation occurring in the ST portion of the electrocardiogram signal, we filter out bad ST change parameters that are not changing at a rate representative of human ischemia ST change parameter rates of change. This can be used for driving therapy systems to alleviate cardiac ischemia. This filtering can be enhanced by using multiple cardiac electrical vectors for the electrogram signal vectors, and using a determination of Axis shift to modify filter parameters and the expected ranges of precursors to the ST change parameter (an ST change variable) to eliminate bad cardiac cycles, that is cardiac cycle information that may be misleading.

Abstract: As particularly useful for implantable medical devices we teach a method and apparatus for orienting electrocardiogram input from electrodes of unknown vector orientation. This can be used for locating a fiducial point in the electrocardiogram signal by which other parameterization of measurements taken of the electrocardiogram signal can be made. It is of particular relevance in any cardio electrogram reading where the orientation of the electrogram signal is unknown, and knowledge of the orientation and a fiducial point can form the basis for useful analysis of electrogram signals for detection of physiologic conditions.

Abstract: In using electrogram signals to determine physiologic conditions like ischemia, the bad cardiac cycle information due to noise, axis shifts in the cardiac electrical axis, and the like must be removed if the electrogram signal can be made to be a good indicator. If this is accomplished through the adaptive filtering techniques shown here, the signal can be used to drive a closed loop therapy system responsive to those physiologic conditions discernible from good cardiac cycle electrocardiogram signals.

Abstract: An implantable medical device determines activity levels over a set of time periods, preferably on the order of seconds, minutes and hours and a display is enabled for days or weeks at recorded activity levels over a range of dates. This enables physician review of patient functional status. Additional physiologic data can be recorded along with the activity data, and this too may be reported out from the implanted device to a medical communications system for alarm purposes, titrating drugs or other monitoring tasks.

Abstract: A system for communicating with a medical device implanted in an ambulatory patient and for locating the patient in order to selectively monitor device function, alter device operating parameters and modes and provide emergency assistance to and communications with a patient. The implanted device includes a telemetry transceiver for communicating data and operating instructions between the implanted device and an external patient communications control device that is either worn by or located in proximity to the patient within the implanted device tranceiving range. The control device preferably includes a communication link with a remote medical support network, a global positioning satellite receiver for receiving positioning data identifying the global position of the control device, and a patient activated link for permitting patient initiated personal communication with the medical support network.