Abstract: An implantable medical device with an inductive switching regulator having an inductor with a ferromagnetic core is described. The device incorporates a core saturation detector for detecting saturation in the inductor core indicating the presence of a magnetic field such as produced by an MRI scan. The device is configured to alter its behavior when core saturation is detected such as by entering an MRI mode that may include cessation of therapy, fixed-rate bradycardia pacing, and/or disablement of tachyarrhythmia therapy.

Abstract: One aspect of this disclosure relates to a system for dynamic battery management in implantable medical devices. An embodiment of the system includes two or more devices for measuring battery capacity for an implantable medical device battery. The embodiment also includes a controller connected to the measuring devices. The controller is adapted to combine the measurements from the measuring devices using a weighted average to determine battery capacity consumed. According to various embodiments, at least one of the measuring devices includes a coulometer. At least one of the measuring devices includes a capacity-by-voltage device, according to an embodiment. The system further includes a display in communication with the controller in various embodiments. The display is adapted to provide a depiction of battery longevity in units of time remaining in the life of the implantable medical device battery, according to various embodiments. Other aspects and embodiments are provided herein.

Abstract: A medical device can include a therapy circuit configured to provide a specified electrostimulation therapy to a tissue site, the specified electrostimulation therapy including a scheduled completion, the therapy circuit including a protection circuit configured to adjust specification of the electrostimulation therapy being provided so as to provide an adjusted electrostimulation therapy before the scheduled completion. The medical device can include a monitoring circuit comprising a comparator. The monitoring circuit can be configured to trigger the protection circuit to inhibit the therapy circuit when the therapy circuit output parameter exceeds the specified threshold as indicated by the comparator.

Abstract: An apparatus comprises an electrostimulation energy storage capacitor, a circuit path that provides pacing stimulation from the capacitor through the load, a constant current neural stimulation circuit that is switchable into the circuit path to provide neural stimulation through the load and switchable out of the circuit path to provide the pacing stimulation through the load, and a control circuit configured to selectively enable delivery of the pacing stimulation or the constant current neural stimulation.

Abstract: One aspect of this disclosure relates to a system for dynamic battery management in implantable medical devices. An embodiment of the system includes two or more devices for measuring battery capacity for an implantable medical device battery. The embodiment also includes a controller connected to the measuring devices. The controller is adapted to combine the measurements from the measuring devices using a weighted average to determine battery capacity consumed. According to various embodiments, at least one of the measuring devices includes a coulometer. At least one of the measuring devices includes a capacity-by-voltage device, according to an embodiment. The system further includes a display in communication with the controller in various embodiments. The display is adapted to provide a depiction of battery longevity in units of time remaining in the life of the implantable medical device battery, according to various embodiments. Other aspects and embodiments are provided herein.

Abstract: An implantable or other ambulatory medical device can include a magnetic field detector, such as configured to detect an intense magnetic field. In an example, the ambulatory or implantable medical device can include an inductive switching supply, such as including one or more of a peak current comparator, or a zero current comparator. In an example, the ambulatory or implantable medical device can include a controller circuit, configured to control a switch, such as to controllably charge an inductor included in the inductive switching supply.

Abstract: An ambulatory or implantable device, such as a pacer, defibrillator, or other cardiac rhythm management device, can tolerate magnetic resonance imaging (MRI) or other noise without turning on an integrated circuit diode by selectively providing a bias voltage that can overcome an expected induced voltage resulting from the MRI or other noise.

Abstract: An implantable medical device with an inductive switching regulator having an inductor with a ferromagnetic core is described. The device incorporates a core saturation detector for detecting saturation in the inductor core indicating the presence of a magnetic field such as produced by an MRI scan. The device is configured to alter its behavior when core saturation is detected such as by entering an MRI mode that may include cessation of therapy, fixed-rate bradycardia pacing, and/or disablement of tachyarrhythmia therapy.

Abstract: During auto-threshold, autocapture, or other evoked response sensing, post-pace artifact is reduced by using a smaller coupling capacitor value than what is used when not in such an evoked response sensing configuration. This can be accomplished by borrowing another capacitor for use as the coupling capacitor. The borrowed capacitor can be a backup pacing capacitor from the same or a different pacing channel. The borrowed capacitor can also be a coupling capacitor from a different pacing channel.

Abstract: An implantable medical device configured to deliver a defibrillation energy to a heart can sense a left ventricular activation using information received from a unipolar sensing or pacing vector defined between a left ventricle and an internal thoracic location external to a heart.

Abstract: An implantable medical device with an inductive switching regulator having an inductor with a ferromagnetic core is described. The device incorporates a core saturation detector for detecting saturation in the inductor core indicating the presence of a magnetic field such as produced by an MRI scan. The device is configured to alter its behavior when core saturation is detected such as by entering an MRI mode that may include cessation of therapy, fixed-rate bradycardia pacing, and/or disablement of tachyarrhythmia therapy.

Abstract: One aspect of this disclosure relates to a system for dynamic battery management in implantable medical devices. An embodiment of the system includes two or more devices for measuring battery capacity for an implantable medical device battery. The embodiment also includes a controller connected to the measuring devices. The controller is adapted to combine the measurements from the measuring devices using a weighted average to determine battery capacity consumed. According to various embodiments, at least one of the measuring devices includes a coulometer. At least one of the measuring devices includes a capacity-by-voltage device, according to an embodiment. The system further includes a display in communication with the controller in various embodiments. The display is adapted to provide a depiction of battery longevity in units of time remaining in the life of the implantable medical device battery, according to various embodiments. Other aspects and embodiments are provided herein.

Abstract: Systems, devices and methods are provided for measuring battery current. According to one aspect, a medical device is provided that comprises a battery, a pulse generator, and a current measuring device. The pulse generator draws a pulse generator current from the power source, and the current measuring device determines the pulse generator current or tracks charge depletion from the battery. The current measuring device comprises an oscillator and a counter. The oscillator produces an oscillating output with a frequency of oscillation dependent on the pulse generator current, and the counter provides an oscillation count for the oscillating output. The current measuring device is capable of being calibrated while continuously determining the pulse generator current. In one embodiment, the current measuring device includes at least two current sources, each including an operational amplifier that has an autozeroing feature.

Abstract: A cardiac rhythm management apparatus may include a monitored energy source, a reference energy source, and a measurement module. The monitored source provides an initial pacing amplitude voltage and a pacing droop voltage, while the reference source provides a substantially fixed reference voltage. The measurement module, coupled to the monitored source and the reference source, provides a measurement related to the lead impedance associated with the rhythm management apparatus that is substantially independent of the reference voltage. Thus, a system may include the apparatus coupled to a lead wire. An article may cause a machine to implement a method which operates to determine a ratio of the actual initial pacing amplitude voltage to the actual pacing droop voltage.

Abstract: Systems, devices and methods are provided for measuring battery current. According to one aspect, a medical device is provided that comprises a battery, a pulse generator, and a current measuring device. The pulse generator draws a pulse generator current from the power source, and the current measuring device determines the pulse generator current or tracks charge depletion from the battery. The current measuring device comprises an oscillator and a counter. The oscillator produces an oscillating output with a frequency of oscillation dependent on the pulse generator current, and the counter provides an oscillation count for the oscillating output. The current measuring device is capable of being calibrated while continuously determining the pulse generator current. In one embodiment, the current measuring device includes at least two current sources, each including an operational amplifier that has an autozeroing feature.

Abstract: A cardiac rhythm management apparatus may include a monitored energy source, a reference energy source, and a measurement module. The monitored source provides an initial pacing amplitude voltage and a pacing droop voltage, while the reference source provides a substantially fixed reference voltage. The measurement module, coupled to the monitored source and the reference source, provides a measurement related to the lead impedance associated with the rhythm management apparatus that is substantially independent of the reference voltage. Thus, a system may include the apparatus coupled to a lead wire. An article may cause a machine to implement a method which operates to determine a ratio of the actual initial pacing amplitude voltage to the actual pacing droop voltage.

Abstract: Systems, devices and methods are provided for measuring battery current. According to one aspect, a medical device is provided that comprises a battery, a pulse generator, and a current measuring device. The pulse generator draws a pulse generator current from the power source, and the current measuring device determines the pulse generator current or tracks charge depletion from the battery. The current measuring device comprises an oscillator and a counter. The oscillator produces an oscillating output with a frequency of oscillation dependent on the pulse generator current, and the counter provides an oscillation count for the oscillating output. The current measuring device is capable of being calibrated while continuously determining the pulse generator current. In one embodiment, the current measuring device includes at least two current sources, each including an operational amplifier that has an autozeroing feature.

Abstract: Systems, devices and methods are provided for measuring battery current. According to one aspect, a medical device is provided that comprises a battery, a pulse generator, and a current measuring device. The pulse generator draws a pulse generator current from the power source, and the current measuring device determines the pulse generator current or tracks charge depletion from the battery. The current measuring device comprises an oscillator and a counter. The oscillator produces an oscillating output with a frequency of oscillation dependent on the pulse generator current, and the counter provides an oscillation count for the oscillating output. The current measuring device is capable of being calibrated while continuously determining the pulse generator current. In one embodiment, the current measuring device includes at least two current sources, each including an operational amplifier that has an autozeroing feature.

Abstract: A cardiac rhythm management (CRM) device detects transthoracic impedance, extracts ventilation or other information, and adjusts a delivery rate of the CRM therapy accordingly. A four-phase sequence of alternating direction current pulse stimuli is periodically delivered to a patient's thorax. A transthoracic impedance signal is extracted using a weighted demodulation. Signal processing extracts ventilation information and removes cardiac stroke information using an adaptive lowpass filter. The adaptive filter cutoff frequency is based on the patient's heart rate; a higher cutoff frequency is provided for higher heart rates. Peak/valley detection indicates tidal volume, which is integrated to extract minute ventilation (MV). Short and long term averages are formed and compared to establish a MV indicated rate. Rate adjustment ignores MV information when a noise-measurement exceeds a threshold.

Abstract: Systems, devices and methods are provided for measuring battery current. According to one aspect, a medical device is provided that comprises a battery, a pulse generator, and a current measuring device. The pulse generator draws a pulse generator current from the power source, and the current measuring device determines the pulse generator current or tracks charge depletion from the battery. The current measuring device comprises an oscillator and a counter. The oscillator produces an oscillating output with a frequency of oscillation dependent on the pulse generator current, and the counter provides an oscillation count for the oscillating output. The current measuring device is capable of being calibrated while continuously determining the pulse generator current. In one embodiment, the current measuring device includes at least two current sources, each including an operational amplifier that has an autozeroing feature.