Abstract: An implantable medical device (IMD) communication system and associated method for controlling the telemetry link status between an IMD and associated programmer during a telemetry session are provided. The system includes control circuitry for detecting conditions during predetermined time intervals for determining if a telemetry session is active or inactive. If a telemetry session is determined to be inactive for a specified interval of time, the telemetry link may be terminated or converted to a low-output, stand-by mode. Patient or device identity verification may be required prior to allowing programmer-IMD communication. A patient alert signal may be generated in response to programmer-IMD communication occurring after a predetermined time of telemetry session inactivity.

Abstract: A bus system is provided for implantable medical devices. The bus system provides for flexible and reliable communication between subsystems in an implantable medical device. The bus system facilitates a wide variety of communications between various subsystems. These various subsystems can include one or more sensing devices, processors, data storage devices, patient alert devices, power management devices, signal processing and other devices implemented to perform a variety of different functions.

Abstract: An implantable medical device (IMD) communication system and associated method for controlling the telemetry link status between an IMD and associated programmer during a telemetry session are provided. The system includes control circuitry for detecting conditions during predetermined time intervals for determining if a telemetry session is active or inactive. If a telemetry session is determined to be inactive for a specified interval of time, the telemetry link may be terminated or converted to a low-output, stand-by mode. Patient or device identity verification may be required prior to allowing programmer-IMD communication. A patient alert signal may be generated in response to programmer-IMD communication occurring after a predetermined time of telemetry session inactivity.

Abstract: An implantable medical device (IMD) communication system and associated method for controlling the telemetry link status between an IMD and associated programmer during a telemetry session are provided. The system includes control circuitry for detecting conditions during predetermined time intervals for determining if a telemetry session is active or inactive. If a telemetry session is determined to be inactive for a specified interval of time, the telemetry link may be terminated or converted to a low-output, stand-by mode. Patient or device identity verification may be required prior to allowing programmer-IMD communication. A patient alert signal may be generated in response to programmer-IMD communication occurring after a predetermined time of telemetry session inactivity.

Abstract: An implantable medical device (IMD) communicates with an external processing unit by transmitting device data and configuration information that describes the device data. The external processing unit processes the device data for display based on the configuration information. The IMD notifies the external processing unit of a change to characteristics of the device data by transmitting the changed device data and updated configuration information.

Abstract: Determining termination of an identified tachyarrhythmia episode may involve analysis of a relative decrease in tachyarrhythmia rate, a normalization of electrogram morphology criteria, or both. An implanted medical device may obtain a tachyarrhythmia rate and a morphology of a cardiac waveform. The device may compare the tachyarrhythmia rate to a threshold tachyarrhythmia rate and the morphology to a template morphology, and classify the heart beat as indicating termination of the tachyarrhythmia episode when the tachyarrhythmia rate is less than the threshold tachyarrhythmia rate, the morphology categorizes as normal, or both. For arrhythmias with no therapy delivered, observation of arrhythmia behavior at the point of termination may lead to improved classification. In addition, observation of a relative decrease in tachyarrhythmia rate immediately after therapy application can lead to application of slower but more specific criteria for redetection.

Abstract: The invention provides systems to prevent the delivery of anti-tachycardia pacing (ATP) following a defibrillation threshold (DFT) induction at implant. An algorithm that classifies episodes as induced or spontaneous is implemented, thereby enabling the ATP during charging feature to be operable only when spontaneous episodes are detected while temporarily suspending the ATP feature during the delivery of defibrillation shock after induction has been confirmed. Further, a user interface enables users to interact with an implantable medical device (IMD), particularly for setting a defibrillation threshold (DFT) or a 50 Hz burst from a single programmer screen. The user interface includes various functionalities to promote quick user access to parameters that govern diagnosis, therapy and other features of the IMD. A single screen enables the user to complete automatic and/or manual DFT inductions or a 50 Hz burst from a programmer interface while acquiring associated documentation from the same interface.

Abstract: Determining termination of an identified tachyarrhythmia episode may involve analysis of a relative decrease in tachyarrhythmia rate, a normalization of electrogram morphology criteria, or both. An implanted medical device may obtain a tachyarrhythmia rate and a morphology of a cardiac waveform. The device may compare the tachyarrhythmia rate to a threshold tachyarrhythmia rate and the morphology to a template morphology, and classify the heart beat as indicating termination of the tachyarrhythmia episode when the tachyarrhythmia rate is less than the threshold tachyarrhythmia rate, the morphology categorizes as normal, or both. For arrhythmias with no therapy delivered, observation of arrhythmia behavior at the point of termination may lead to improved classification. In addition, observation of a relative decrease in tachyarrhythmia rate immediately after therapy application can lead to application of slower but more specific criteria for redetection.

Abstract: A device-implemented software system operates a detection window and adjusts PAV as needed after confirming the presence or detection of evidence of an arrhythmia. The detection window is monitored based on a preferred length. If the detection window is shorter than required, intervals are adjusted for a specific pacing rate. Further, the software system provides means for selecting detection over pacing based on an analysis of a preferred length in the presence of evidence of an arrhythmia.

Abstract: Methods for improving detection of arrhythmias by adaptively increasing arrhythmia detection intervals. One method includes increasing the V2V, the overall cardiac cycle length, thereby decreasing the pacing rate in the presence of ventricular safety paces (VSPs). Another method includes shortening the trigger interval following the atrial pace event, during which time the pacemaker will detect V-sense events, while leaving the A2V VSP interval unchanged, at the end of which any required VSP will be generated. In yet another method, the interval from A-pace to V-pace, the PAV interval, is shortened, while leaving the overall V2V cycle interval unchanged. This increases the ventricular to artial V2A interval, increasing the detection window for arthythmias. The PAV interval can be shortened in response to a recent history of VSP events.

Abstract: The invention presents techniques for reducing the interference to telemetry from an implanted medical device caused by a source of controllable noise. In the context of an implanted system that includes a defibrillator system and a telemetry system, for example, the invention reduces the interference by suspending energy storage during telemetry. The invention further provides for suspending energy storage operation gradually rather than abruptly, by gradually reducing the duty cycle of a clock that controls the energy storage.

Abstract: The invention provides systems to prevent the delivery of anti-tachycardia pacing (ATP) following a defibrillation threshold (DFT) induction at implant. An algorithm that classifies episodes as induced or spontaneous is implemented, thereby enabling the ATP during charging feature to be operable only when spontaneous episodes are detected while temporarily suspending the ATP feature during the delivery of defibrillation shock after induction has been confirmed. Further, a user interface enables users to interact with an implantable medical device (IMD), particularly for setting a defibrillation threshold (DFT) or a 50 Hz burst from a single programmer screen. The user interface includes various functionalities to promote quick user access to parameters that govern diagnosis, therapy and other features of the IMD. A single screen enables the user to complete automatic and/or manual DFT inductions or a 50 Hz burst from a programmer interface while acquiring associated documentation from the same interface.

Abstract: A device-implemented software system operates a detection window and adjusts PAV as needed after confirming the presence or detection of evidence of an arrhythmia. The detection window is monitored based on a preferred length. If the detection window is shorter than required, intervals are adjusted for a specific pacing rate. Further, the software system provides means for selecting detection over pacing based on an analysis of a preferred length in the presence of evidence of an arrhythmia.

Abstract: Methods for improving detection of arrhythmias by adaptively increasing arrhythmia detection intervals. One method includes increasing the V2V, the overall cardiac cycle length, thereby decreasing the pacing rate in the presence of ventricular safety paces (VSPs). Another method includes shortening the trigger interval following the atrial pace event, during which time the pacemaker will detect V-sense events, while leaving the A2V VSP interval unchanged, at the end of which any required VSP will be generated. In yet another method, the interval from A-pace to V-pace, the PAV interval, is shortened, while leaving the overall V2V cycle interval unchanged. This increases the ventricular to artial V2A interval, increasing the detection window for arthythmias. The PAV interval can be shortened in response to a recent history of VSP events.

Abstract: In general, the invention is directed to techniques for using a magnet to suspend a function of an implanted device, and to verify that the function has been suspended. A suspension device emits a magnetic field to suspend a function of a device implanted in a body, receives a signal that the function has been suspended, and outputs an indicator that the function has been suspended. In this manner, an operator can proceed having confidence that the suspension of the function was completed, and did not fail due to inappropriate placement of the magnet, slippage, or any other of a number of reasons.

Abstract: The invention presents techniques for reducing the interference to telemetry from an implanted medical device caused by a source of controllable noise. In the context of an implanted system that includes a defibrillator system and a telemetry system, for example, the invention reduces the interference by suspending energy storage during telemetry. The invention further provides for suspending energy storage operation gradually rather than abruptly, by gradually reducing the duty cycle of a clock that controls the energy storage.

Abstract: A cyclic redundancy code (CRC) and optionally a syndrome value calculation of one or more implantable medical device (IMD) data block is conducted by block mover/reader hardware of the IMD when the data block(s) are moved and/or read. In the block read operation, each data byte or word in the block mover data register is read in a first clock cycle. In the block move operation, each data byte is read in the first clock cycle in this way and then moved to a destination register in a second clock cycle. The data CRC and optionally the syndrome value accumulate in the CRC and syndrome registers as all data bytes of the data block(s) are read in the first clock cycle.

Abstract: An implantable device which stores information indicative of events occurring within a patient's body and related to operation of the device for transmission to an external device in response to a request from the external device. The implanted device is provided with a mechanism for retaining information as to the state of the information stored in the device at the time of a preceding request or interrogation from the external device and for storing cumulative information indicative of the operation of the device or events occurring within the patient's body over a time frame spanning multiple interrogations or requests from the external device. The two types of stored information together may be employed by the implanted device or the external device to derive information indicative only of events occurring since a preceding interrogation of the implanted device by the external device.

Abstract: An apparatus and method for protecting memory content of a programmable memory is disclosed. A programmable memory, such as a random access memory (RAM), is configured to include a write protected portion defined as part of the programmable memory. The write protected memory portion may be configured within the memory space of a single programmable memory, or implemented in a logically or physically separate programmable memory. A microprocessor is coupled to the programmable memory and generates an access code for providing write access to the write protected portion of the programmable memory. A logic circuit, coupled to the programmable memory and microprocessor verifies the access code received from the microprocessor. In response to a verified access code, the logic circuit enables write access to the write protected portion of the programmable memory. In response to an unverified access code, the logic circuit disables write access to the write protected portion of the programmable memory.

Abstract: An implantable device which stores information indicative of events occurring within a patient's body and related to operation of the device for transmission to an external device in response to a request from the external device. The implanted device is provided with a mechanism for retaining information as to the state of the information stored in the device at the time of a preceding request or interrogation from the external device and for storing cumulative information indicative of the operation of the device or events occurring within the patient's body over a time frame spanning multiple interrogations or requests from the external device. The two types of stored information together may be employed by the implanted device or the external device to derive information indicative only of events occurring since a preceding interrogation of the implanted device by the external device.