Abstract: A hybrid battery power source for implantable medical use provides a generally constant low internal resistance during discharge and avoids voltage delays of the type that develop as a result of run down-induced resistance increase in Li/SVO cells. The hybrid battery power source utilizes two batteries or cells, one being a primary cell of relatively high energy density and the other being a secondary cell of relatively low internal resistance that is rechargeable. The primary and secondary cells are connected in a parallel arrangement via a voltage boost/charge control circuit that is powered by the primary cell and adapted to charge the secondary cell while limiting charge/discharge excursions thereof in a manner that optimizes its output for high energy medical device use. The energy storage capacitors of the medical device in which the hybrid battery power source is situated are driven by the secondary cell. The primary cell is used to as an energy source for recharging the secondary cell.

Abstract: Implantable medical devices in embodiments of the invention may include one or more of the following features: (a) a hermetic enclosure, (b) a low-power control circuit located in the enclosure, (c) a high-power output circuit located in the enclosure for delivering an electrical pulse therapy, (d) a power source and circuitry located in the enclosure for powering the low-power control circuit and the high-power output circuit, the power source and circuitry, (e) a first high-rate cell, (f) a second high-rate cell electrically connected in parallel to the low-power control circuit and the high-power output circuit, (g) and at least one resistive load electrically connected between the first high-rate cell and the second high-rate cell, the at least one resistive load having a resistive value to limit, in the event of an internal short in one of the high-rate cells, the rate by which the shorted high-rate cell drains the other high-rate cell.

Abstract: A hybrid battery power source for implantable medical use provides a generally constant low internal resistance during discharge and avoids voltage delays of the type that develop as a result of run down-induced resistance increase in Li/SVO cells. The hybrid battery power source utilizes two batteries or cells, one being a primary cell of relatively high energy density and the other being a secondary cell of relatively low internal resistance that is rechargeable. The primary and secondary cells are connected in a parallel arrangement via a voltage boost/charge control circuit that is powered by the primary cell and adapted to charge the secondary cell while limiting charge/discharge excursions thereof in a manner that optimizes its output for high energy medical device use. The energy storage capacitors of the medical device in which the hybrid battery power source is situated are driven by the secondary cell. The primary cell is used to as an energy source for recharging the secondary cell.

Abstract: A hybrid battery power source for implantable medical use provides relatively stable resistance during discharge and avoids the voltage delays that develop as a result of variable resistance increase in Li/SVO cells. The hybrid battery power source utilizes two batteries or cells, one being a primary battery of relatively high energy density and the other being a rechargeable secondary battery of low relatively stable internal resistance. The primary and secondary batteries are connected in a parallel arrangement, preferably via an intermediate voltage boost circuit having an inductor and a pulse generating control circuit therein. The energy storage capacitors of the medical device in which the hybrid battery power source is situated are driven in whole or substantial part by the secondary battery. The primary battery is used to as an energy source for recharging the secondary battery.

Abstract: A hybrid battery power source for implantable medical use provides a generally constant low internal resistance during discharge and avoids voltage delays of the type that develop as a result of run down-induced resistance increase in Li/SVO cells. The hybrid battery power source utilizes two batteries or cells, one being a primary cell of relatively high energy density and the other being a secondary cell of relatively low internal resistance that is rechargeable. The primary and secondary cells are connected in a parallel arrangement via a voltage boost/charge control circuit that is powered by the primary cell and adapted to charge the secondary cell while limiting charge/discharge excursions thereof in a manner that optimizes its output for high energy medical device use. The energy storage capacitors of the medical device in which the hybrid battery power source is situated are driven by the secondary cell. The primary cell is used to as an energy source for recharging the secondary cell.

Abstract: An electrically active medical implant has a circuit (5), at least one first battery (1) to supply low current, and a second battery (2) to supply high current into the circuit (5), and a control device (4) designed to disconnect the at least one first battery (1) from circuit (5), and to connect second battery (2) to circuit (5), where a capacitor (3) connected in a parallel arrangement with battery (1), where the capacitor can be charged by the first battery both during a first circuit status, during which the first battery is connected to circuit (5), and during a second circuit status, during which circuit (5) is connected only to second battery (2), where control device (4) again disconnects second battery (2) from circuit (5) at the end of the second circuit status, and connects the parallel arrangement consisting of first battery (1) and capacitor (3) to circuit (5) for further energy supply.

Abstract: An implantable medical device having a dual cell power source powering a high-power output circuit and a low-power control circuit. The power source includes a first, high-rate cell and a second, lower-rate cell having a rate capability less than a rate capability of the first, high-rate cell. The first and second cells are electrically connected to the output circuit and control circuit by circuitry. In one embodiment, the circuitry connects the first and second cells in parallel to the output circuit and the control circuit, and includes a switching circuit for selectively uncoupling the first, high-rate cell from the control circuit during a transient high power pulse. In another embodiment, the first and second cells are formed within a single case and are connected in parallel to the output circuit and the control circuit.

Abstract: A method and apparatus are provided for distributing power within a cardiac treatment and monitoring system which includes a defibrillator releasably coupled to a patient monitoring unit. The method includes the steps of determining a battery reserve capacity within the patient monitoring unit and distributing power from the patient monitoring system to a defibrillator when the determined battery reserve capacity exceeds a threshold value.

Abstract: An implantable cardiac device has a pulse generator configured to generate electric shocks for delivery to a patient's heart. The device has an output capacitor, and connected charging circuitry. A first battery is switchably coupled to the charging circuitry, and has a high current flow rate to rapidly charge the capacitor. A second battery is switchably connected in parallel to the first battery, and is operable to recharge the first battery. A detector coupled to the charging circuitry detects when the recharging current is above a predetermined threshold indicative of abnormal recharging. A controller is programmed to enable the charging circuitry to produce the shocks, and to disable the second battery whenever an abnormal recharging current is detected. The controller may operate to connect the batteries on anti parallel whenever an abnormal recharging current is detected.

Abstract: An implantable medical device having a dual cell power source powering a high-power output circuit and a low-power control circuit. The power source includes a first, high-rate cell and a second, lower-rate cell having a rate capability less than a rate capability of the first, high-rate cell. The first and second cells are electrically connected to the output circuit and control circuit by circuitry. In one embodiment, the circuitry connects the first and second cells in parallel to the output circuit and the control circuit, and includes a switching circuit for selectively uncoupling the first, high-rate cell from the control circuit during a transient high power pulse. In another embodiment, the first and second cells are formed within a single case and are connected in parallel to the output circuit and the control circuit.

Abstract: An apparatus and method that will allow for external communication, via an external programmer, for positive device identification and for retrieval of device or patient information stored by an implantable medical device with a depleted power source. The external programmer will deliver energy to a secondary power source located inside the implanted device using RF telemetry sufficient to charge up the secondary power source, e.g., a small capacitor. The capacitor will charge up immediately within milliseconds. Once the secondary power source is sufficiently charged, it can be used to power up a controller having the stored information in the implantable medical device. Once the controller is operational, the implanted device will transmit device and patient information to the external programmer via RF telemetry.

Abstract: It is important in cardiac pacing devices and systems to achieve efficient power utilization and conservation to extend the life of the battery cells, thereby extending the intervals between invasive medical procedures to replace components in the cardiac pacing system. A device and method are provided. The cardiac pacing device comprises a battery, a discrete time switched capacitor pacing power supply comprising a charge transfer capacitor bank comprising at least two capacitors, and a pace output supply capacitor which can discharge current to the tissue of a patient. A pacing supply design has a multiplicity of battery voltage multiplication factors and operating frequency settings. The pacing supply, voltage multiplier settings and operating frequency are automatically adjusted to compensate for changing pace output settings, load, cardiac cycle rate, and/or battery condition.

Abstract: The output stage of a tissue stimulating apparatus, for example a cochlear implant prosthesis, operating at a low supply voltage (35) incorporates a multiplier circuit (54, 62, 63, 64) for ensuring that voltage compliance is maintained in the event that high intensity stimulations are required. The multiplier circuit makes use of compliance monitoring so that multiplication is only used as required. Also described is a method for operating a tissue stimulating apparatus incorporating a multiplier circuit.

Abstract: A power control system is described for use in an implantable cardioverter-defibrillator (ICD) having a low-power cell and a high-power cell. The power control system includes a fuzzy logic controller for gradually varying the relative amounts of energy drawn from the low- and high-power cells based upon a selected function to be performed by the ICD and upon various operational parameters of the ICD. Example functions include cardioversion therapy, cardiac defibrillation, cardiac pacing, cardiac monitoring and capacitor reformation. Example operational parameters include the remaining capacities of the low- and high-power cells, the amount of time since implant of the ICD, the number of defibrillation shocks already delivered, and the amount of pacing energy previously utilized.

Abstract: A device and method for performing automatic battery maintenance as particularly applied in an implantable cardioverter defibrillator (ICD). The battery is maintained at a predetermined state-of-charge to enable charging a capacitor in the ICD to discharge high voltage pulse into a human patient via electrodes implanted in the patient.

Abstract: An implantable cardioverter defibrillator having a plurality of high voltage capacitors in the output stage which are coupled in parallel and a switching matrix for controlling the number of capacitors used to deliver the shock. For patients having lower DFTs, the number of capacitors in the output stage, as controlled by the switching matrix, can be reduced thus reducing the capacitor charging time prior to delivering a defibrillation shock. Additionally, if one of the capacitors experiences a degradation in performance, it can be switched out of the output circuit as long as the remaining capacitors can provide the necessary energy delivery for defibrillation. In another embodiment of the invention, if a particular defibrillation shock is ineffective, the back-up capacitors may be switched into the high voltage output circuit for delivery of the next shock.

Abstract: A pacemaker has logic incorporated for holding the pacemaker circuitry, or at least a portion of such circuitry, in a low current drain "standby" mode of operation from time of fabrication until time of implantation or preparation for implantation, in order to minimize battery depletion during shelf life. In one embodiment, the pacemaker detects when a lead has been connected to the pulse generator output so as to present an impedance below a predetermined threshold, and such detection is used to take the pacemaker out of the "standby" mode and place it in a fully operational mode. The pacemaker is further provided for sensing an externally generated signal in response to which the pacemaker is placed in an operational mode for a predetermined time duration, following which it reverts to the standby mode.

Abstract: An improved dual battery power system uses two separate battery power sources for an implantable cardioverter defibrillator, each having optimized characteristics for monitoring functions and for output energy delivery functions, respectively. The monitoring functions are supplied electrical power by a first battery source, such as a conventional pacemaker power source in the form of a lithium iodide battery which is optimized for long life at very low current levels. The output energy delivery functions are supplied by a separate second battery source, such as a pair of lithium vanadium pentoxide batteries, which is optimized for high current drain capability and low self-discharge for long shelf life. The first battery source provides electrical power only to the monitoring functions of the implantable cardioverter defibrillator, and the second battery source provides all of the electrical power for the output energy delivery functions.

Abstract: A pacemaker having a fault-tolerant elective replacement indicator (ERI) triggering scheme in which transient excursions of parameters used as criteria for triggering ERI are rejected as triggering events. Periodic assessments of certain indicia of battery depletion are made, and subjected to a long-term low-pass filtering operation in order to reduce the effects of transient excursions of the indicia which result from non-ERI conditions. Over a long period of time (e.g., a day) predetermined threshold values of the indicia of interest must be exceeded a predetermined number of times in order for the device to issue an ERI. In one disclosed embodiment of the invention, the battery's loaded terminal voltage and internal impedance are used as indicators of the battery's depletion level. Periodically, these values are measured and converted to digital values.

Abstract: A pacemaker contains at least one power-consuming component, such as a sensor with associated electronic circuitry for controlling the pacemaker function or a heart signal detector, and an electrode system for emitting heart stimulation pulses. The power-consuming component is disenabled prior to implantation of the pacemaker. Circuitry is provided for enabling the power-consuming component which is responsive to an event occurring substantially simultaneously with pacemaker implantation in the patient. Such circuitry may include a device for measuring the electrode impedance so as to enable the power-consuming component in response to the measured impedance value. The circuitry for enabling the power-consuming component can alternatively includes internal telemetry equipment in the pacemaker and external telemetry equipment for communications between the telemetry equipments.

Abstract: A device for reducing power consumption in medical electrical equipment, implantable in the human body, having a sensor, which includes a sensor element and sensor electronic circuitry for sensing a parameter relevant to control of the equipment's in vivo operation, also has a comparator which compares the sensor element's output signal to a predesignated threshold value and switches the sensor electronic circuitry from a passive mode with low power consumption to an active mode with heavier power consumption or vice-versa, depending on the magnitude of the sensor element's signal in relation to the threshold value.

Abstract: An implantable electromedical device having a detachable, replaceable power supply. In one embodiment, the circuitry for an electromedical device is contained in a first hermetic enclosure, while a power supply for the device is contained in a second hermetic enclosure. The two enclosures are coupled together via a multiple conductor lead or the like, using any of the known assemblies commonly used for connection of pacing/sensing leads to an implantable device. A control signal generated by the device is applied to a control terminal on the battery enclosure. When the control signal is asserted, the battery is electrically coupled to two battery terminals on the battery enclosure, which terminals are coupled to power input terminals on the device itself. When the control signal is deserted, the battery is decouple from the battery terminals, so that there is no leakage current associated with the conduction of battery voltages on the connector between the two hermetic capsules.