Abstract: In an example, an implantable medical device (IMD) includes a hold capacitor configured to deliver an electrical therapy pulse, and charge pump circuitry configured to transfer energy from the battery to the hold capacitor. In this example, the charge pump circuitry comprises a plurality of capacitors, and switching circuitry configured to put the charge pump circuitry into a K-factor mode selected from a group of K-factor modes by opening and closing a combination of switches connected to the plurality of capacitors.

Abstract: Techniques for facilitating improved power management for an implantable device are provided. In one example, an implantable device includes a telemetry circuit and a power management circuit. The telemetry circuit is configured to facilitate a telemetry session between the implantable device and an external device. The power management circuit is configured to connect a power supply to the telemetry circuit via a first current-limiting device based on a determination that the telemetry circuit satisfies a defined criterion. The power management circuit is also configured to connect the telemetry circuit to a second current-limiting device based on a determination that the telemetry circuit is connected to the first current-limiting device for a defined period of time.

Abstract: An extra-cardiovascular implantable cardioverter defibrillator (ICD) is configured to induce a tachyarrhythmia by charging a high voltage capacitor to a voltage amplitude and delivering a series of pulses to a patient's heart by discharging the capacitor via an extra-cardiovascular electrode vector. Delivering the series of pulses includes recharging the high-voltage capacitor during an inter-pulse interval between consecutive pulses of the series of pulses.

Abstract: An implantable device system for delivering electrical stimulation pulses to a patient's body includes a pulse delivery device having a piezoelectric element that is enclosed by a housing and produces voltage signals delivered to the patient's body in response to receiving ultrasound energy. The pulse delivery device includes a circuit having a rate limiter configured to filter voltage signals produced by the piezoelectric element a rate faster than a maximum stimulation rate.

Abstract: An implantable device system for delivering electrical stimulation pulses to a patient's body includes a pulse delivery device having a piezoelectric element that is enclosed by a housing and produces voltage signals delivered to the patient's body in response to receiving ultrasound energy. The pulse delivery device includes a circuit having a rate limiter configured to filter voltage signals produced by the piezoelectric element a rate faster than a maximum stimulation rate.

Abstract: An implantable medical device system is configured to deliver cardiac pacing by receiving a cardiac electrical signal by sensing circuitry of a first device via a plurality of sensing electrodes, identifying by a control module of the first device a first cardiac event from the cardiac electrical signal, setting a first pacing interval in response to identifying the first cardiac event, controlling a power transmitter of the first device to transmit power upon expiration of the first pacing interval, receiving the transmitted power by a power receiver of a second device; and delivering at least a portion of the received power to a patient's heart via a first pacing electrode pair of the second device coupled to the power receiver.

Abstract: An implantable medical device system is configured to deliver cardiac pacing by receiving a cardiac electrical signal by sensing circuitry of a first device via a plurality of sensing electrodes, identifying by a control module of the first device a first cardiac event from the cardiac electrical signal, setting a first pacing interval in response to identifying the first cardiac event, controlling a power transmitter of the first device to transmit power upon expiration of the first pacing interval, receiving the transmitted power by a power receiver of a second device; and delivering at least a portion of the received power to a patient's heart via a first pacing electrode pair of the second device coupled to the power receiver.

Abstract: An implantable medical device is configured to control a therapy module to couple a capacitor array comprising a plurality of capacitors to a plurality of extra-cardiovascular electrodes and control the therapy module to deliver a composite pacing pulse to a patient's heart via the plurality of extra-cardiovascular electrodes by sequentially discharging at least a portion of the plurality capacitors to produce a series of at least two individual pulses that define the composite pacing pulse.

Abstract: An extra-cardiovascular implantable cardioverter defibrillator (ICD) having a low voltage therapy module and a high voltage therapy module is configured to select, by a control module of the ICD, a pacing output configuration from at least a low-voltage pacing output configuration of the low voltage therapy module and a high-voltage pacing output configuration of the high voltage therapy module. The high voltage therapy module includes a high voltage capacitor having a first capacitance and the low voltage therapy module includes a plurality of low voltage capacitors each having up to a second capacitance that is less than the first capacitance. The ICD control module controls a respective one of the low voltage therapy module or the high voltage therapy module to deliver extra-cardiovascular pacing pulses in the selected pacing output configuration via extra-cardiovascular electrodes coupled to the ICD.

Abstract: An extra-cardiovascular implantable cardioverter defibrillator (ICD) is configured to induce a tachyarrhythmia by charging a high voltage capacitor to a voltage amplitude and delivering a series of pulses to a patient's heart by discharging the capacitor via an extra-cardiovascular electrode vector. Delivering the series of pulses includes recharging the high-voltage capacitor during an inter-pulse interval between consecutive pulses of the series of pulses.

Abstract: This disclosure is directed to techniques for delivering cardiac pacing pulses to a patient's heart by a cardiac system, such as an extra-cardiovascular ICD system. An ICD operating according to the techniques disclosed herein delivers cardiac pacing pulses using high-voltage therapy circuitry typically configured for delivering high-voltage cardioversion/defibrillation shocks. The ICD delivers the high-voltage pacing therapy via extra-cardiovascular electrodes, such as one or more extra-cardiovascular electrodes carried by a medical electrical lead extending from the ICD and/or the housing of the ICD.

Abstract: An implantable device and associated method for delivering multi-site pacing therapy is disclosed. The device comprises a set of electrodes including a first ventricular electrode and a second ventricular electrode, spatially separated from one another and all coupled to an implantable pulse generator. The device comprises a processor configured for selecting a first cathode and a first anode from the set of electrodes to form a first pacing vector at a first pacing site along a heart chamber and selecting a second cathode and a second anode from the set of electrodes to form a second pacing vector at a second pacing site along the same heart chamber. The pulse generator is configured to deliver first pacing pulses to the first pacing vector and delivering second pacing pulses to the second pacing vector. The pulse generator generates a recharging current for recharging a first coupling capacitor over a first recharge time period in response to the first pacing pulses.

Abstract: Methods and/or devices may be configured to monitor the performance of pacing therapy and provide fault-tolerant operation to provide therapy in the event of certain failure modes occurring in the pacing delivery circuits, leads, and/or lead/tissue interfaces. Generally, the methods and/or devices may provide fault-detection, fault-recovery and fault-handling to, e.g., handle potential faults.

Abstract: Example techniques for communicating between two medical devices are described. One medical device may be an implantable medical device. Another medical device may be a lead-borne implantable medical device. The lead-borne implantable medical device may be referred to as a satellite. The implantable medical device may measure impedance of a path including at least two electrodes, at least one of which is on the lead, using an impedance measurement module. In some example implementations of this disclosure, the implantable medical device may also use the impedance measurement module to communicate with the satellite on the lead.

Abstract: Methods for estimating a remaining service life of an implantable medical device (IMD) battery are presented. In one embodiment, a characteristic discharge model of the battery is employed. Systems employing the methods may include an external device coupled to the IMD, for example, via a telemetry communications link, wherein a first portion of a computer readable medium included in the IMD is programmed to provide instructions for the measurement, or tracking, of time and the measurement of battery voltage, and a second portion of the computer readable medium included in the external device is programmed to provide instructions for carrying out the calculations when the voltage and time data is transferred via telemetry from the IMD to the external device.

Abstract: A system and method for determining complex intercardiac impedance to detect various cardiac functions are disclosed involving a signal generator means for providing an adjustable direct current signal, a modulator for modulating the adjustable direct current signal to produce a modulated signal, at least one electrode for propagating the modulated signal across a myocardium, at least one sensor for detecting an outputted modulated signal from the myocardium, and at least one circuit to reduce the influence of process noise (aggressors) in the outputted modulated signal. The at least one circuit comprises an amplifier, a demodulator, and an integrator. The amplitude and phase of the final outputted modulated signal indicate the complex impedance of the myocardium. Changes in the complex impedance patterns of the myocardium provide indication of reduced oxygen and blood flow to the myocardium.

Abstract: A system for monitoring trends in lead impedance includes collecting data from various sources in an implantable medical device system. Lead impedance, non-physiologic sensed events percentage of time in mode switch, results of capture management operation, sensed events, adversion pace counts, refractory sense counts and similar data are used to determine the status of a lead. A set of weighted sum rules are implemented by a software system to process the data and provide displayable information to health care professionals via a programmer. The lead monitoring system includes a patient alert system for patients to seek help in the event a serious lead condition is identified.

Abstract: A system includes a memory and a processing module. The memory includes a primary sensing vector and N alternate sensing vectors. The processing module determines a ranking value for each of the N alternate sensing vectors. Each ranking value is indicative of the integrity of a cardiac electrical signal acquired via the corresponding alternate sensing vector. The processing module senses cardiac events using the primary sensing vector, detects a reduction in the integrity of a cardiac electrical signal acquired via the primary sensing vector, and selects one of the N alternate sensing vectors in response to detecting a reduction in the integrity of the cardiac electrical signal acquired via the primary sensing vector. The selection is based on the ranking value associated with the one of the N alternate sensing vectors. The processing module then senses cardiac events using the selected one of the N alternate sensing vectors.

Abstract: Example techniques for communicating between two medical devices are described. One medical device may be an implantable medical device. Another medical device may be a lead-borne implantable medical device. The lead-borne implantable medical device may be referred to as a satellite. The implantable medical device may measure impedance of a path including at least two electrodes, at least one of which is on the lead, using an impedance measurement module. In some example implementations of this disclosure, the implantable medical device may also use the impedance measurement module to communicate with the satellite on the lead.

Abstract: An implantable lead for use with a medical device (IMD) includes active circuits incorporated into the lead to reduce the creation of an induced current, or dissipate the induced current and heat created due to an induced current in the lead. The active circuits are powered by the magnetic resonant imaging energy or interfering magnetic or electrical fields. According to various embodiments, the lead and/or its components can be provided to reduce or dissipate a current and heat induced by various external magnetic or electrical fields.