Medtronic, Inc.

Angeion Corporation

David Manufacturing Company

Dennis A Brumwell

Mark W Kroll

Theodore P Adams

Joseph S Perttu

Joseph F Lessar

Jeffrey A Schweitzer

Michael D Baudino

Charles G Supino

Gene A Bornzin

Michael D De Franco

Kenneth M Anderson

Larry L Stille

Keith A Braun

Ann M Donohoo

Alan A Moore

Frank R Dropps

James E Brewer

Glenn M Roline

Scott T Latterell

Randall S Nelson

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.

Dual battery power system for an implantable cardioverter defibrillator with voltage booster

A method and an apparatus for performing a device component failure analysis in an implantable medical device using current consumption data. A current consumption signal relating to current consumption in an implantable medical device is generated. The current consumption signal is then processed. A defect of a component in the implantable medical device is assessed in response to the processing of the current consumption signal and appropriate action is taken, such as selecting alternate therapies, generating an alert signal, and turning off circuits corresponding to the assessed defect.

Current monitor for an implantable medical device

An amplified, isolated output control circuit is provided for controlling the output switching network of a self-powered defibrillator that delivers a high voltage electrical countershock through a plurality of electrodes. The defibrillator comprises a low voltage battery system, a high voltage capacitor system, a high voltage transformer connected between the battery system and the capacitor system, and an output switching network, such as an H-bridge switching network, connected between the capacitor system and the plurality of electrodes. The defibrillator is controlled by control circuitry that manages the charging and discharging of the electrical countershock and is connected to the output control circuitry. Preferably, the output control circuitry includes an isolated power supply, at least one optoisolator device and at least one amplifier circuit that is powered by the isolated power supply and is connected between the optoisolator device and a switch of the output switching network. The output control circuitry provides for actual high side control of the output switching network by allowing the high side switches of the output switching network to be turned on and off after the low side switches of the output switching network. Preferably, the isolated power supply also provides a boosted output that powers the control circuitry at least during charging of the capacitor system to insure an adequate supply of power.

Amplified voltage output switching network for a self-powered

An implantable medical device, such as an implantable cardioverter defibrillator (ICD), utilizes a heat-shrink conforming shield to substantially isolate internal components and circuitry from the device housing and from each other. Preferably, the shield also protects the internal circuitry of the device from undesirable electro-magnetic coupling effects. The shape conforming isolation material provides an inexpensive, effective isolation barrier that helps shield the circuitry from undesired coupling effects and also protects the components from inadvertent shorts as well as potential damage during assembly and testing.

Implantable medical device having heat-shrink conforming shield

An implantable cardioverter defibrillator capable of subcutaneous positioning within a patient delivers at least one electrical cardioversion/defibrillation countershocks to the heart of the patient. The implantable cardioverter defibrillator includes a housing, circuitry positioned within the housing to control delivery of the countershocks, and an energy source coupled with the circuitry to provide electrical energy to a capacitor in the circuitry that stores the electrical energy for delivery of the countershocks. Because the circuitry is susceptible to undesirable electromagnetic coupling effects of origin external to the circuitry, particularly the capacitive coupling effects between the circuitry and the housing of the device when at least a portion of the housing is utilized as an electrode, the implantable cardioverter defibrillator also includes a conductive shield, disposed between the housing and the circuitry, to shield the circuitry against such undesired coupling effects.

Shield for implantable cardioverter defibrillator

An ICD detection method for sensing the occurrence of an R-wave improves the ability to distinguish R-waves from noise through the use of variable declining sensitivity thresholds. The method includes the consideration of the amplitude of at least the previous most recent R-wave to determine a declining threshold of sensitivity used to recognize a subsequent electrical signal as an R-wave. In the method, the amplitude of the previous R-wave may be classified, based upon amplitude, and based upon the classification, a desirable time constant for the declining threshold of sensitivity is provided as an exponential or reverse exponential decay. Alternatively, a piece wise use of various decay formulas may be combined and used to avoid false recognition of noise as an R-wave.

R-wave detection method for implantable cardioverter defibrillators

A staged energy storage system provides electrical energy to an implantable biomedical device by using the combination of a first stage energy source and a second stage energy concentration system. The second stage energy concentration system allows a lower density and/or lower voltage energy source to be used as the first stage energy source, thereby decreasing the battery cost, size and weight. In one embodiment, the second stage energy concentration system comprises a rechargeable battery. In another embodiment, the second stage energy capacitor system comprises a high energy density capacitor system. The staged energy storage system is ideal for internally charging a pulse-generating capacitor system within an implantable cardioverter defibrillator. In this embodiment, a high voltage transformer has a secondary side that is electrically connected to the pulse-generating capacitor system. A second stage concentration system is electrically connected between a first stage energy source and a primary side of the high voltage transformer to store at least a portion of an electrical charge that is delivered from the first stage energy source and to the high voltage transformer.

Staged energy concentration for an implantable biomedical device

A main energy delivery electrical circuit for use in an implantable cardioverter defibrillator device comprises a low power output primary defibrillator battery, a high power output intermediate power intensifying capacitor system, a switch for permitting the intermediate power intensifying capacitor system to rapidly charge a main energy delivery capacitor, and a main energy delivery capacitor. The main energy delivery capacitor is configured for discharging, in a first pulse, an electrical charge derived from the primary battery, and for discharging certain subsequent pulses of electrical charge derived from the intermediate power intensifying capacitor system. The circuit permits the implantable cardioverter defibrillator device to deliver multiple closely spaced defibrillation pulses to a heart.

System and method for delivering multiple closely spaced defibrillation

The present invention uses switches to set the topology and polarity of a circuit that includes capacitors to deliver an electric pulse to a heart during a defibrillation procedure. The waveform of the electric pulse is biphasic, in that it is a positive portion of the pulse followed by a negative portion of the pulse. The topology and polarity of the circuit are utilized to produce a waveform that approximates the ideal waveform for the specific situation. The circuit provides for combinations of capacitors variously in series and in parallel and changing the topology and polarity of the circuit during discharge of the capacitors.

Implantable defibrillator system with capacitor switching circuitry

The first embodiment of the present invention repositions the shunt thyristor used in the monophasic-waveform generator of the prior art so that it discharges the main capacitor through a series thyristor, thus increasing current through it briefly, rather than reducing current through it. The result of this arrangement is that the node between the series thyristor and the heart is pulled rapidly to a low voltage, causing the shunt switch to discharge the cardiac capacitance, as well as the main capacitance. The consequence is that discharging the cardiac capacitance requires a reversal of current in the heart, which enhances the heart-stimulating effect of the defibrillating waveform. The resulting true-voltage-pulse waveform has an efficacy approximating that of a biphasic waveform and is achieved with a circuit no more complex than that used to generate a monophasic waveform. A second and alternative embodiment of the present invention is a defibrillation system comprising a switching-bridge circuit, augmented by a zener diode and a rectifier diode, that is capable of delivering on demand any one of the waveforms known as monophasic, biphasic, and true-voltage-pulse waveforms.

Improved implantable defibrillator system for producing

Dual battery power system for an implantable cardioverter defibrillator

A monitoring system for an oxygen sensing, dual-wavelength, reflectance oximetry based, rate responsive cardiac pacemaker, is capable of automatically and continually adjusting an oxygen sensor signal comparator threshold such that the effects of noise, sensitivity and drift on oximeter output signals sent to the pacemaker are minimized. A comparator and related circuitry are configured to sample and compare supply excitations for multiple oxygen sensor light sources. The comparator threshold is adjusted as a function of supply excitation for each light source independently of one another, thereby providing an oxygen sensing pacemaker with optimal noise immunity since one of the more vulnerable portions of the pacing system is the transfer of the light source signals which are susceptible to noise.

Apparatus and method of automatically adjusting a sensor signal

A control system for a drying system of the type including a drying bin. Discharge particulate material moisture sensing means including a sensor assembly positioned in a discharge auger for sensing the moisture content of the particulate material. Control means is connected to the discharge particulate moisture sensing means and the discharge auger for controlling operation of the discharge auger.

Grain dryer control system and method using moisture sensor

An improved atrial synchronous, dual chamber pacemaker provided with a variable refractory period during which the pacemaker is not responsive to the sensed atrial contractions. The atrial refractory period is varied as a function of measured atrial and ventricular rates, and corresponds to a predetermined proportion of the lesser of the average interval separating the ventricular contractions and the average interval separating atrial contractions. The invention is particularly beneficial in the context of a VDD type pacemaker.

Growing community of inventors

Bloomington, MN, United States of America

Dennis A Brumwell