Abstract: An implantable medical device implements a special mode of operation, such as a mode of electrical stimulation therapy, during conditions where there may be an increased likelihood that a device reset will occur. The implantable medical device recovers from the device reset by copying values that specify the special mode and that are stored in a non-volatile memory to an operating memory. The special mode is implemented after the device reset has occurred by using the values copied to the operating memory. One version of the special mode is an MRI mode that allows the implantable medical device to safely operate during an MRI scan. The fields of the MRI scan may trigger a device reset, but the MRI mode values are copied from the non-volatile memory to the operating memory, and the MRI mode is implemented after the reset by using the values copied to the operating memory.

Abstract: An implantable medical device implements a special mode of operation, such as a mode of electrical stimulation therapy, during conditions where there may be an increased likelihood that a device reset will occur. The implantable medical device recovers from the device reset by copying values that specify the special mode and that are stored in a non-volatile memory to an operating memory. The special mode is implemented after the device reset has occurred by using the values copied to the operating memory. One version of the special mode is an MRI mode that allows the implantable medical device to safely operate during an MRI scan. The fields of the MRI scan may trigger a device reset, but the MRI mode values are copied from the non-volatile memory to the operating memory, and the MRI mode is implemented after the reset by using the values copied to the operating memory.

Abstract: An implantable medical device implements a special mode of operation, such as a mode of electrical stimulation therapy, during conditions where there may be an increased likelihood that a device reset will occur. The implantable medical device recovers from the device reset by copying values that specify the special mode and that are stored in a non-volatile memory to an operating memory. The special mode is implemented after the device reset has occurred by using the values copied to the operating memory. One version of the special mode is an MRI mode that allows the implantable medical device to safely operate during an MRI scan. The fields of the MRI scan may trigger a device reset, but the MRI mode values are copied from the non-volatile memory to the operating memory, and the MRI mode is implemented after the reset by using the values copied to the operating memory.

Abstract: A device includes a housing configured to be implanted in a patient. The device also includes a first magnetic field direction sensor located at a first location within the housing and configured to generate a signal representative of a first direction of a magnetic field at the first location, a second magnetic field direction sensor located at a second location within the housing and configured to generate a signal representative of a second direction of the magnetic field at the second location, and a magnetic field strength sensor configured to generate a signal representative of a strength of the magnetic field. The device further includes a control module configured to identify a source of the magnetic field based on at least one of the signal representative of the strength of the magnetic field and the signals representative of the first and second directions of the magnetic field.

Abstract: An implantable medical device implements a special mode of operation, such as a mode of electrical stimulation therapy, during conditions where there may be an increased likelihood that a device reset will occur. The implantable medical device recovers from the device reset by copying values that specify the special mode and that are stored in a non-volatile memory to an operating memory. The special mode is implemented after the device reset has occurred by using the values copied to the operating memory. One version of the special mode is an MRI mode that allows the implantable medical device to safely operate during an MRI scan. The fields of the MRI scan may trigger a device reset, but the MRI mode values are copied from the non-volatile memory to the operating memory, and the MRI mode is implemented after the reset by using the values copied to the operating memory.

Abstract: An implantable medical device implements a special mode of operation, such as a mode of electrical stimulation therapy, during conditions where there may be an increased likelihood that a device reset will occur. The implantable medical device recovers from the device reset by copying values that specify the special mode and that are stored in a non-volatile memory to an operating memory. The special mode is implemented after the device reset has occurred by using the values copied to the operating memory. One version of the special mode is an MRI mode that allows the implantable medical device to safely operate during an MRI scan. The fields of the MRI scan may trigger a device reset, but the MRI mode values are copied from the non-volatile memory to the operating memory, and the MRI mode is implemented after the reset by using the values copied to the operating memory.

Abstract: Per the disclosure subcutaneously implantable medical devices (IMDs) with rate responsive implantable pulse generator (IPG) capability that also include dual patient activity sensors are adaptively controlled. One of the activity sensors uses multiple electrodes adapted to acquire electrocardiographic signals and signals from non-cardiac muscle tissue (myopotentially-based signals). The signals from the electrode-based activity sensor are used to confirm and/or override the patient-activity sensor signals from the other non-myopotentially-based patient activity sensor. The electrodes are directly mechanically coupled to the housing of the IMD and electrically coupled to circuitry that filters, processes, and interprets both the patient activity sensor signals.

Abstract: Techniques are described for selectively enabling and disabling a pre-stimulation passive recharge pacing mode for an implantable medical device (IMD) depending on whether the IMD is operating in an electromagnetic interference (EMI)-safe mode. In some examples, the IMD may enable the pre-stimulation passive recharge pacing mode when the IMD is operating in the EMI-safe mode, and disable the pre-stimulation passive recharge pacing mode when the IMD is not operating in the EMI-safe mode. The EMI-safe mode may be, in some examples, a magnetic resonance imaging (MRI)-safe mode.

Abstract: This disclosure provides an implantable medical device comprising a power source a therapy module that includes at least one energy storage component, and a charging module coupled between the power source and the therapy module. The charging module is configured to control charging of the at least one energy storage component of the therapy module. The charging module may be further configured to detect a condition indicative of improper charging, to detect a condition indicative of the implantable medical device being subjected to fields generated by an magnetic resonance imaging (MRI) device, and to terminate charging of the at least one energy storage component when both the condition indicative of improper charging and the condition indicative of the implantable medical device being subjected to fields generated by the MRI device are detected.

Abstract: An implantable medical system may include an implantable medical lead including at least one electrode and an implantable medical device. The implantable medical device comprises an electromagnetic interference (EMI) detection module that monitors for one or more particular characteristics of EMI. A control module is configured to control a therapy module to generate monophasic stimulation pulses while operating the IMD in a first operating mode. In response to detecting the condition indicative of the presence of EMI, the control module switches the IMD from the first operating mode to a second operating mode and generates at least one multiphasic stimulation pulses while operating the IMD in the second operating mode.

Abstract: An implantable medical system may include an implantable medical lead including at least one electrode and an implantable medical device. The implantable medical device comprises an electromagnetic interference (EMI) detection module that monitors for one or more particular characteristics of EMI. A control module is configured to control a therapy module to generate single stimulation pulses while operating the IMD in a first operating mode. In response to detecting the condition indicative of the presence of EMI, the control module switches the IMD from the first operating mode to a second operating mode and generates at least one group of two or more stimulation pulses in close proximity to one another in place of a single stimulation pulse while operating the IMD in the second operating mode.

Abstract: An implantable medical device implements a special mode of operation, such as a mode of electrical stimulation therapy, during conditions where there may be an increased likelihood that a device reset will occur. The implantable medical device recovers from the device reset by copying values that specify the special mode and that are stored in a non-volatile memory to an operating memory. The special mode is implemented after the device reset has occurred by using the values copied to the operating memory. One version of the special mode is an MRI mode that allows the implantable medical device to safely operate during an MRI scan. The fields of the MRI scan may trigger a device reset, but the MRI mode values are copied from the non-volatile memory to the operating memory, and the MRI mode is implemented after the reset by using the values copied to the operating memory.

Abstract: An implantable medical device may include a telemetry module, a sensing module, a therapy delivery module, and a processor. The processor may be configured to detect a patient event based on data generated by the sensing module, operate the IMD in a first mode in which the telemetry module is disabled and the therapy delivery module is at least partially disabled when the patient event is not detected, and operate the IMD in a second mode in which the telemetry module is enabled and the therapy delivery module is at least partially disabled when the patient event is detected. In some examples, the processor is configured to, in the second mode, generate a notification of the cardiac arrhythmia and transmit the notification to an external device via the telemetry module. The external device may reside inside an MRI room or outside the MRI room, and may communicate with other devices.

Abstract: An implantable medical device may include a telemetry module, a sensing module, a therapy delivery module, and a processor. The processor may be configured to detect a patient event based on data generated by the sensing module, operate the IMD in a first mode in which the telemetry module is disabled and the therapy delivery module is at least partially disabled when the patient event is not detected, and operate the IMD in a second mode in which the telemetry module is enabled and the therapy delivery module is at least partially disabled when the patient event is detected. In some examples, the processor is configured to, in the second mode, generate a notification of the cardiac arrhythmia and transmit the notification to an external device via the telemetry module. The external device may reside inside an MRI room or outside the MRI room, and may communicate with other devices.

Abstract: Techniques are described for controlling effects caused when an implantable medical device (IMD) is subject to a disruptive energy field. The IMD may include an implantable lead that includes one or more electrodes. The IMD may further include a first component having a parasitic inductance. The IMD may further include a second component having a reactance. In some examples, the reactance of the second component may be selected based on the parasitic inductance of the first component such that an amount of energy reflected along the lead in response to energy produced by an electromagnetic energy source is below a selected threshold. In additional examples, the parasitic inductance of the first component and the reactance of the second component are configured such that an amount of energy reflected along the lead in response to a frequency of electromagnetic energy is below a selected threshold.

Abstract: In general, this disclosure is directed to techniques and circuitry to determine characteristics of an implantable lead associated with an implantable medical device (IMD). The implantable lead may be designed to be MRI-safe by having one or more components that attenuate frequencies associated with an MRI that, if left unreduced, may interfere with the performance of the lead and/or cause harm to the tissue in which the lead is implanted. The circuitry may transmit a signal through the lead and receive a response signal. The device may determine the lead characteristics by comparing the transmitted signal with the received signal. In addition to determining whether the lead is MRI-safe, the techniques of this disclosure may be also utilized to determine whether the lead is faulty.

Abstract: A device includes a housing configured to be implanted in a patient. The device also includes a first magnetic field direction sensor located at a first location within the housing and configured to generate a signal representative of a first direction of a magnetic field at the first location, a second magnetic field direction sensor located at a second location within the housing and configured to generate a signal representative of a second direction of the magnetic field at the second location, and a magnetic field strength sensor configured to generate a signal representative of a strength of the magnetic field. The device further includes a control module configured to identify a source of the magnetic field based on at least one of the signal representative of the strength of the magnetic field and the signals representative of the first and second directions of the magnetic field.

Abstract: This disclosure provides an implantable medical device comprising a power source a therapy module that includes at least one energy storage component, and a charging module coupled between the power source and the therapy module. The charging module is configured to control charging of the at least one energy storage component of the therapy module. The charging module may be further configured to detect a condition indicative of improper charging, to detect a condition indicative of the implantable medical device being subjected to fields generated by an magnetic resonance imaging (MRI) device, and to terminate charging of the at least one energy storage component when both the condition indicative of improper charging and the condition indicative of the implantable medical device being subjected to fields generated by the MRI device are detected.

Abstract: Techniques are described for controlling effects caused when an implantable medical device (IMD) is subject to a disruptive energy field. The IMD may include an implantable lead that includes one or more electrodes. The IMD may further include a first component having a parasitic inductance. The IMD may further include a second component having a reactance. In some examples, the reactance of the second component may be selected based on the parasitic inductance of the first component such that an amount of energy reflected along the lead in response to energy produced by an electromagnetic energy source is below a selected threshold. In additional examples, the parasitic inductance of the first component and the reactance of the second component are configured such that an amount of energy reflected along the lead in response to a frequency of electromagnetic energy is below a selected threshold.

Abstract: This disclosure describes techniques for reducing, and possibly eliminating, adverse effects caused by signals induced on an inductive antenna of an implanted medical device by varying magnetic fields from a source of interference, such as the gradient magnetic fields applied during an MRI procedure. For example, the implantable medical device includes an inductive antenna that receives signals via inductive coupling, a filter circuit that attenuates signals induced on the inductive antenna by varying magnetic fields generated from a source of interference and substantially passes signals induced on the inductive antenna by varying magnetic fields generated by an expected source and a telemetry module that processes the signals from the filter circuit.