US3926198A - Cardiac pacer - Google Patents

Cardiac pacer Download PDF

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US3926198A
US3926198A US574199A US57419975A US3926198A US 3926198 A US3926198 A US 3926198A US 574199 A US574199 A US 574199A US 57419975 A US57419975 A US 57419975A US 3926198 A US3926198 A US 3926198A
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Prior art keywords
battery
casing
pacer
cardiac pacer
circuit means
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US574199A
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Steve A Kolenik
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Intermedics Inc
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ARCO Medical Products Co
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Priority to US574199A priority Critical patent/US3926198A/en
Priority to CA226,750A priority patent/CA1041609A/en
Priority to DE19752524815 priority patent/DE2524815A1/en
Priority to LU72670A priority patent/LU72670A1/xx
Priority to GB24462/75A priority patent/GB1491069A/en
Priority to BR4650/75D priority patent/BR7503630A/en
Priority to FR7517874A priority patent/FR2273511A1/en
Priority to JP50070097A priority patent/JPS517783A/ja
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Assigned to INTERMEDICS, INC., INTERMEDICS CARDIASSIST, INC., INTERMEDICS INTRAOCULAR, INC., SURGITRONICS CORPORATION, CARBOMEDICS, INC., NEUROMEDICS, INC., CALCITEK, INC., TEXAS CORPORATION AND AMERICAN PACEMAKER CORPORATION, A CORP OF MASS. reassignment INTERMEDICS, INC., INTERMEDICS CARDIASSIST, INC., INTERMEDICS INTRAOCULAR, INC., SURGITRONICS CORPORATION, CARBOMEDICS, INC., NEUROMEDICS, INC., CALCITEK, INC., TEXAS CORPORATION AND AMERICAN PACEMAKER CORPORATION, A CORP OF MASS. SECURED PARTY HEREBY RELEASE THE SECURITY INTEREST IN AGREEMENT RECORDED AUGUST 5, 1985. REEL 4434 FRAMES 728-782 Assignors: CITIBANK, N.A.
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Assigned to INTERMEDICS, INC., INTERMEDICS CARDIASSIST, INC., INTERMEDICS INTRAOCULAR, INC., SURGITRONICS CORPORATION, CARBOMEDICS, INC., NEUROMEDICS, INC., CALCITEK, INC., INTERVASCULAR, INC., AND MASTER IMAGES, INC., TEXAS CORPORATIONS, AND AMERICANPACEMAKER CORPORATION, A CORP. OF MA. reassignment INTERMEDICS, INC., INTERMEDICS CARDIASSIST, INC., INTERMEDICS INTRAOCULAR, INC., SURGITRONICS CORPORATION, CARBOMEDICS, INC., NEUROMEDICS, INC., CALCITEK, INC., INTERVASCULAR, INC., AND MASTER IMAGES, INC., TEXAS CORPORATIONS, AND AMERICANPACEMAKER CORPORATION, A CORP. OF MA. SAID PARTIES RECITES OBLIGATIONS RECITED IN SECURITY AGREEMENT RECORDED SEPTEMBER 17, 1984 REEL 4303 FRAMES 077-127 HAVE BEEN PAID IN FULL ALL SEE RECORD FOR DETIALS Assignors: CITIBANK, N.A., INDIVIDUALLY AND AS AGENT FOR BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION, THE CHASE MANHATTAN BANK, N.A., THE FIRST NATIONAL BANK OF CHICAGO, TRUST COMPANY BANK, FIRST FREEPORT NATIONAL BANK OF BRAZOSPORT BANK OF TEXAS
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Assigned to INTERMEDICS CARDIASSIST, INC., A TEXAS CORP., SURGITRONICS CORPORATION, A TEXAS CORP., INTERMEDICS, INC., A TEXAS CORP., NEUROMEDICS, INC., A TEXAS CORP., CARBOMEDICS, INC., A TEXAS CORP., AMERICAN PACEMAKER CORPORATION, A MASSACHUSETTS CORP., CALCITEK, INC., A TEXAS CORP., INTERMEDICS INTRAOCULAR, INC., A TEXAS CORP. reassignment INTERMEDICS CARDIASSIST, INC., A TEXAS CORP. RELEASED BY SECURED PARTY (SEE DOCUMENT FOR DETAILS). Assignors: B. A. LEASING CORPORATION
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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372Arrangements in connection with the implantation of stimulators
    • A61N1/378Electrical supply
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372Arrangements in connection with the implantation of stimulators
    • A61N1/375Constructional arrangements, e.g. casings
    • A61N1/37512Pacemakers

Definitions

  • This invention relates to cardiac pacers suitable for implantation and particularly to overcoming the adverse side effects heretofore observed in connection with prior art use of some types of implantable cardiac pacers.
  • any implantable cardiac pacer must be sufficiently miniaturized to permit surgical placement in a cavity within the body.
  • the lead or conduit or catheter
  • An electrical conduit sometimes called a catheter, transmits the electrical signals from the implanted cardiac pacer to an appropriate signal-receiving zone of the heart.
  • a significant portion of implanted cardiac pacers have employed batteries comprising mercury.
  • Such mercury batteries generate a gas which must be vented from the battery chamber. Such venting has complicated the problem of preventing the eventual penetration of body fluids into undesired portions of the cardiac pacer.
  • the durability of a mercury battery has permitted usage for more than a year but generally less than 4 years.
  • a variety of other types of batteries, including batteries comprising a lithium anode, have been proposed for use with cardiac pacers but the numerous problems related to the long-term reliability has left most of the needs unanswered.
  • a cardiac pacer is maintained at a weight less than 100 grams and at a specific gravity less than 1.7, whereby the inertia forces attributable to acceleration and deceleration are below the threshold of significant trouble to the tissue adjacent the cavity of implantation, whereby the patient may wear the implanted cardiac pacer with greater comfort than prior art cardiac pacers.
  • Such small size and low specific gravity for the heart pacer are attributable in part to the utilization of oscillator means featuring the use of complementary metal oxide semiconductor devices which not merely occupy a small volume, but more particularly utilize significantly less power per day, whereby the battery life is significantly prolonged.
  • the sub-threshold weight, sub-threshold density, and acceptable battery life are achieved in part by the combination of said complementary metal oxide semiconductor devices and a battery featuring the combination of a lithium anode and a thionyl chloride electrolyte.
  • No gas is evolved by the generation of current from the thionyl chloride type battery.
  • One of the most significant and unique characteristics of such thionyl chloride battery is the attainment of a voltage of about 3.3 volts or more over a battery life of more than 5 years.
  • the invention features a metal casing effective in shielding the electric components from electromag netic interference. At least two lithium thionyl chloride type batteries may desirably be maintained in parallel with circuit means protecting the pacer from interferences attributable to failure of one battery while assuring redundant reliability of parallel batteries.
  • the smallness of the cardiac pacer permits its implantation in an infant a few weeks old, thus fulfilling a long-standing demand for a pediatric pacer for cardiac patients.
  • FIG. 1 is a schematic drawing showing a heart pacer implanted in a body so that the electrical conduit can direct stimulating pulse to an appropriate zone of a heart.
  • FIG. 2 is a schematic drawing of a sub-threshold inertia cardiac pacer of the present invention.
  • FIG. 3 is a perspective view of the heart pacer.
  • FIG. 4 is a schematic partially sectional end view of FIG. 3.
  • FIG. 5 is a schematic showing of a heart pacer exerting forces upon the tissue of the walls of the cavity in which it is placed. Differential acceleration and/or deceleration attributable to differential inertia of the heart pacer relative to such adjoining tissue during periods when rapid shifts of acceleration and/or deceleration occur, impart such forces upon such tissues.
  • a heart pacer 10 is electrically and mechanically connected to an electrical conduit 11 carrying electrical impulses to a signal reception zone 12 of a heart 13 of a mammal 14.
  • the electrical conduit may be directed through a vein 15 toward the signal reception zone 12.
  • the heart pacer 10 is implanted within a cavity l6.
  • surgeons have employed any of several cavities such as 17a, l7biand' 17c as alternative cavities for heart pacer implantation.
  • the small size and weight of the heart pacer of the present invention is so much less than that of prior heart-.pac'ers that additional locations might be suitable for implantation;
  • a heart pacer -10 can be posi-. tioned within a cavity 516.
  • the walls 18 of cavity to transmit mechanical forces arising from shifting of heart pacer l0 and may compress and/or stretch tissue 519 near cavity walls 18.
  • FIG. 5 there is a schematic showing of compression of tissue 51% and the stretching of tissue 519a as a result of inertial shifting of heart pacer 516 toward wall 180.
  • the specific gravity of heart pacer 51.0 is greater than the specific gravity of tissue 519 so that when mammal 14 is jerked back and forth, the inertia of heart pacer 510 is not identical to the inertia of the tissue 519, thereby causing differential inertial forces.
  • a heart pacer 210 comprises a casing 230.
  • casing is made of titanium to assure adequate inertness to the biological fluids.
  • a partition 231 divides the interior of the casing into a circuitry chamber 232 and a battery chamber 233.
  • a socket 234 is adapted to receive a plug portion of electrical conduit 11.
  • the socket 234 is an insert within a molded organic polymeric shield 235 which protects a wire 236 extending from upper por- 4 the battery and positive grounding to the casing 230, as by having a casing of the circuitry unit in electrical contact with casing 230.
  • the positive pole of batteries are associated electrically with casing 236.
  • Wires 252 and 253 from passthroughs 254 and 255 are energized respectively by wire 256 from a standard battery and by wire 257 from a supplemental battery.
  • a negativeterminal 258 of standard battery 260 supplies current to wire 256 and thence to pass-through 254, and wire 252 and thence to circuitry means, conveniently designated as circuitry unit (1).
  • supplemental battery 261 supplies current to wire 257, pass-through 255, wire 253 and thence to circuitry unit 256.
  • power from parallel batteries 260 and 261 in chamber 233 is supplied to circuitry, unit 256 in chamber 232.
  • Each of the pass-throughs comprises an insulating member, desirably constructed of alumina, sealed to a pin and brazed in an opening in partition 231, thus closely resembling the structure of pass-through 238.
  • Wires 262 and 263 assure *the good electrical'connection between the positiveposts of batteries 260, 261
  • circuitry chamber 232' is a circuitry unit 250 having an output wire 251 directed to said pass-through" pin 2410.
  • the circuitry unit 250 is energized by the combination of wire means from the negative pole of with casing 230.
  • the batteries 266 and 261 are connected electrically in parallel within hermetically sealed battery chamber 233 andthat the power of two batteries is transmitted through pass-throughs 254 and 255 independently to the circuitry unit 250.
  • Various materials, such as body fluids from cavity 16 and/or fluids within a battery might adversely affect operation of the circuitry unit 250 if any leakage occurred.
  • circuitry chamber 232 is hermetically sealed, both from cavity 16 and from battery chamber 233, the circuitry unit 250 has appropriate protection against any leakage which might occur.
  • casing 36 is hermetically sealed from cavity 16 so that the heart pacer is protected from the effects of liquids and/or gases'in cavity 16.
  • battery 260 features a lithium anode 270 and an electrolyte consisting predominantly of thionyl chloride 271. Because battery 26tl features the combination of lithium anode 270 and thionyl chloride electrolyte 271, its voltage can be as high as 3.64 volts and is assuredly at least 3.3 volts during a lifetime of more than 5 years. Of particular importance,.the voltageof such lithium-thionyl chloride type battery remains substantially constant during substantially all of the life. expectancy of the battery and diminishes significantly only during a few months of theterminal period of use of the battery.
  • the decreasin g voltage and'thus alteration of the pulse rate provides the clue indicative of theappropriateness of a change of batteries. It is especially important that there be a procedure for detection of battery depletion.
  • the combination of lithium anode and thionyl chloride achieves this highly significant desiderata.
  • the signal pulses to the heart represent only about A; of l per cent of the time during which the heart pacer is implanted. Accordingly, the battery life for a heart pacer is significantly influenced by the current drain during the 799/800s fraction of the time when no pulse is sent even though the circuitry unit must be operative. Any demand circuitry sensitive to the normal operation of the heart delivers impulses to the heart during a time fraction less than the delivery time fraction for a fixed rate heart pacer.
  • Early types of heart pacers were based upon circuitry energized by a voltage supply of about 6 volts. Significant power was consumed by 6 volt circuitry, thereby shortening battery life.
  • Circuitry unit 250 is characterized by oscillator means employing complementary metal oxide semiconductor devices operable at a low voltage, so that the two lithium batteries can be connected in parallel instead of in series. Moreover, such complementary metal oxide semiconductor devices of the oscillator means permit the circuitry unit to function much of the time at a current drain which is so small that battery life can be based to a significant extent upon the dissipation of power at the signal reception zone 12 of the heart. The power consumption during the quasi-dormant portion of use is particularly significant in connection with demand pacers, in which the combination of thionyl chloride-lithium batteries and complementary metal oxide semiconductor devices are particularly advantageous.
  • the pacer consists essentially of the combination of a metal casing hermetically sealing the interior zones of the cardiac pacer from exposure to body fluids in the cavity in which the cardiac pacer is implanted, said casing being less than mm thick, and each other orthagonal dimension being less than 60 mm, such small dimensions permitting implantation without troublesome bulging of the skin adjacent the cardiac pacer, said metal casing shielding electrical components from electromagnetic interference; at least one battery in said casing, each battery generating no gas, each battery having a lithium anode and an electrolyte consisting predominantly of thionyl chloride, each battery having prolonged low impedance and constant high voltage of at least 3.3 volts during an expected life of more than 5 years, the voltage diminishing significantly only during the terminal period of use of the battery, whereby detection of battery depletion is manageable; in a preferred embodiment there are wires and pass-throughs within the casing associating at least two batteries in parallel and protecting
  • a cardiac pacer consisting essentially of the combination of:
  • a metal casing hermetically sealing the interior zones of the cardiac pacer from exposure to body fluids in the cavity in which the cardiac pacer is implanted, said casing being less than 20 mm thick, and each other orthagonal dimension being less than mm, such small dimensions permitting implantation without troublesome bulging of the skin adjacent the cardiac pacer, said metal casing shielding electrical components from electro-magnetic interference and constituting a grounding electrode for the cardiac pacer;
  • each battery in said battery chamber, there being an electrical conductor transmitting battery power from each battery to said circuitry chamber, each battery generating no gas, each battery having a lithium anode and an electrolyte consisting predominantly of thionyl chloride, each battery having prolonged low impedance and constant high voltage of at least 3.3 volts during an expected life of more than 5 years, the voltage diminishing significantly only during the terminal period of use of the battery, whereby detection of battery depletion is manageable, the positive pole of the batteries being grounded to the metal casing;
  • wires and pass-throughs within the casing associating at least two batteries in parallel and assuring the redundant reliability of parallel batteries;
  • circuitry unit employing complementary metal oxide semiconductor circuit means for producing pulses adapted to stimulate the heart, said circuit means being electrically energized by current from said batteries, the casing of the circuit means being grounded to the casing of the heart pacer, said circuit means being within said circuitry chamber, said circuit means including an output wire, said wires and pass-throughs being electrically connected to said circuit means;
  • said complementary metal oxide semiconductors and said circuit means consuming such a small amount of power that the battery life is more than 5 years;
  • electrical socket means adapted to transmit to an electrical conduit the output from said circuit means, said electrical conduit being adapted to transmit the output from said circuit means to a signal-receiving zone of a heart, electrical passthrough means connecting said output wire to said socket means;
  • said combination of casing, batteries, wires, passthroughs, circuit means, and electrical socket means having a weight less than grams and a specific gravity less than 1.7, whereby changes in acceleration or deceleration of a body having such implanted cardiac pacer impart only forces which are tolerable to tissue adjacent the cavity in which the cardiac pacer is implanted.

Abstract

The forces which are imparted by a cardiac pacer to adjacent tissues are below the threshold of troublesome difficulty when the body is subjected to acceleration or deceleration. Such below-threshold forces are attributed to controlling the weight of the cardiac pacer to be less than 100 grams, and to controlling the specific gravity to be less than 1.7. Such low density and low weight are attainable by reason of the use of a miniaturized oscillator featuring complementary metal oxide semiconductors consuming such a small power that more than 5 years of life are attainable from the thionyl chloride-lithium type of battery having a prolonged stable voltage of at least 3.3 volts. The cardiac pacer is thin enough to avoid troublesome bulging of the skin adjacent the implanting location.

Description

llnited States Patent Kolenik Dec. 16, 1975 [54] CARDHW PACER OTHER PUBLICATIONS [75] Inventor: Steve Kolemk Leechburg Greatbatch et al., IEEE Transactions on Biomedical [73] Assignee: ARCO Medical Products Company, g n ering, V. ENE-18, N0. 5, Sept. 1971, pp.
Leechburg, Pa. 317423.
[22] Filed May 1975 Primary Examiner-William E. Kamm [21] Appl. No.1 574,199 Attorney, Agent, or Firm-John R. Ewbank Related US. Application Data [63] Continuation-impart of Ser, No. 477,571, June 10, [57] ABSTRACT 1974, abandoned- The forces which are imparted by a cardiac pacer to adjacent tissues are below the threshold of troublel CL 123/419 128/419 128/419 some difficulty when the body is subjected to acceler- 136/156 ation or deceleration. Such below-threshold forces are [51] I111. (11. attributed to ontrolling the weight of the ardiac 1 1 Field Of Search-M 128/419 P, 419 PG, 419 PS, pacer to be less than 100 grams, and to controlling the 128/419 421, 422, 423; 136/86 F, 153; specific gravity to be less than 1.7. Such low density 307/304, 313 and low weight are attainable by reason of the use of a miniaturized oscillator featuring complementary 1 References Cited metal oxide semiconductors consuming such a small UNITED STATES PATENTS power that more than 5 years of life are attainable 3,474,353 10/1969 Keller, Jr. 128/419 PG from the thionyl Chloridelithium yp Of battery 3 20 220 11/1971 Murphy JR I 12 419 p5 ing a prolonged stable voltage of at least 3.3 volts. The 3,649,367 3/1972 Purdy 128/419 P cardiac pacer is thin enoughto avoid troublesome 3,743,923 7/1973 Steudel 307/304 bulging of the skin adjacent the implanting location. 3,822,707 7/1974 Adducci et a1. 128/419 PS 3,835,864 R8801 128/419 PG 3 Claims, 5 Drawing Figures US. Patent Dec. 16, 1975 CARDIAC PACER RELATED APPLICATION This is a continuation-in-part of Ser. No. 477,571, filed June 10, 1974, and now abandoned.
FIELD OF INVENTION This invention relates to cardiac pacers suitable for implantation and particularly to overcoming the adverse side effects heretofore observed in connection with prior art use of some types of implantable cardiac pacers.
HISTORY OF PRIOR ART In a hospital in which a patient under intensive care can receive electrical pulse signals from an external oscillator, the size and complexity of the signal generating apparatus is of only minor importance. Any implantable cardiac pacer, however, must be sufficiently miniaturized to permit surgical placement in a cavity within the body. As used herein, the lead (or conduit or catheter) is deemed a supplement to the pacer, although others have designated the combination of the lead and unit generating pulses as a pacer. An electrical conduit, sometimes called a catheter, transmits the electrical signals from the implanted cardiac pacer to an appropriate signal-receiving zone of the heart. A significant portion of implanted cardiac pacers have employed batteries comprising mercury. Such mercury batteries generate a gas which must be vented from the battery chamber. Such venting has complicated the problem of preventing the eventual penetration of body fluids into undesired portions of the cardiac pacer. The durability of a mercury battery has permitted usage for more than a year but generally less than 4 years. A variety of other types of batteries, including batteries comprising a lithium anode, have been proposed for use with cardiac pacers but the numerous problems related to the long-term reliability has left most of the needs unanswered.
When a heart pacer, which generally weighs from about 200 to 500 grams, is implanted in the body, the bulge in the skin at the zone of implantation is troublesome to the patient. The tissue adjacent the cavity in which the heart pacer is implanted is subjected to severe forces under certain jolting conditions or other rapid acceleration or deceleration conditions in which the inertia of the heart pacer imparts forces to such tissue adjacent the implantation cavity. It is well known that bruising, sense of pain, and/or other biological phenomena are influenced by threshold phenomena. As long as the forces are below the threshold, no biological response is apparent but above the threshold, increasing force involves increasing biological response.
Initially, only older patients were treated with implanted heart pacers. As their usefulness became better known, it was recognized that certain types of cardiac problems in children are best treated with heart pacers. Some children needing implanted heart pacers were too small to permit implantation of the previously available heart pacers, and the continuing reports of deaths of such children has provided a long-standing demand for miniaturized pacers for cardiac patients.
SUMMARY OF THE PRESENT INVENTION In accordance with the present invention, a cardiac pacer is maintained at a weight less than 100 grams and at a specific gravity less than 1.7, whereby the inertia forces attributable to acceleration and deceleration are below the threshold of significant trouble to the tissue adjacent the cavity of implantation, whereby the patient may wear the implanted cardiac pacer with greater comfort than prior art cardiac pacers. Such small size and low specific gravity for the heart pacer are attributable in part to the utilization of oscillator means featuring the use of complementary metal oxide semiconductor devices which not merely occupy a small volume, but more particularly utilize significantly less power per day, whereby the battery life is significantly prolonged. In accordance with the present invention, the sub-threshold weight, sub-threshold density, and acceptable battery life are achieved in part by the combination of said complementary metal oxide semiconductor devices and a battery featuring the combination of a lithium anode and a thionyl chloride electrolyte. No gas is evolved by the generation of current from the thionyl chloride type battery. One of the most significant and unique characteristics of such thionyl chloride battery is the attainment of a voltage of about 3.3 volts or more over a battery life of more than 5 years. The invention features a metal casing effective in shielding the electric components from electromag netic interference. At least two lithium thionyl chloride type batteries may desirably be maintained in parallel with circuit means protecting the pacer from interferences attributable to failure of one battery while assuring redundant reliability of parallel batteries.
The smallness of the cardiac pacer permits its implantation in an infant a few weeks old, thus fulfilling a long-standing demand for a pediatric pacer for cardiac patients.
The nature of the present invention is further clarified by reference to descriptions of appropriate embodiments which merely illustrate and do not restrict the invention.
DESCRIPTION OF DRAWINGS FIG. 1 is a schematic drawing showing a heart pacer implanted in a body so that the electrical conduit can direct stimulating pulse to an appropriate zone of a heart.
FIG. 2 is a schematic drawing of a sub-threshold inertia cardiac pacer of the present invention.
FIG. 3 is a perspective view of the heart pacer.
FIG. 4 is a schematic partially sectional end view of FIG. 3.
FIG. 5 is a schematic showing of a heart pacer exerting forces upon the tissue of the walls of the cavity in which it is placed. Differential acceleration and/or deceleration attributable to differential inertia of the heart pacer relative to such adjoining tissue during periods when rapid shifts of acceleration and/or deceleration occur, impart such forces upon such tissues.
DESCRIPTION OF INVENTION As shown in FIG. 1, a heart pacer 10 is electrically and mechanically connected to an electrical conduit 11 carrying electrical impulses to a signal reception zone 12 of a heart 13 of a mammal 14. The electrical conduit may be directed through a vein 15 toward the signal reception zone 12. The heart pacer 10 is implanted within a cavity l6. Heretofore, surgeons have employed any of several cavities such as 17a, l7biand' 17c as alternative cavities for heart pacer implantation. The small size and weight of the heart pacer of the present invention is so much less than that of prior heart-.pac'ers that additional locations might be suitable for implantation;
As shown in FIG. 5, a heart pacer -10 can be posi-. tioned within a cavity 516. The walls 18 of cavity to transmit mechanical forces arising from shifting of heart pacer l0 and may compress and/or stretch tissue 519 near cavity walls 18.
In FIG. 5, there is a schematic showing of compression of tissue 51% and the stretching of tissue 519a as a result of inertial shifting of heart pacer 516 toward wall 180. The specific gravity of heart pacer 51.0 is greater than the specific gravity of tissue 519 so that when mammal 14 is jerked back and forth, the inertia of heart pacer 510 is not identical to the inertia of the tissue 519, thereby causing differential inertial forces.
Using the heavy heart pacers of the prior art, differences in weight and/or density amongst the heart pacers appear to be of little consequence because all heartventional differential inertial forces, whereby the heart pacer may be worn with significantly greater comfort and with less likelihood of trauma, infection, inflammation, and/or other adverse developments in the tissue adjacent the walls of the cavity in which the heart pacer is implanted. In accordance with the present invention, there is greatly decreased likelihood of discomfort for the person having an implanted heart pacer by reason of the control of the density and weight of the heart pacer to be so low as to be below the threshold of significant discomfort from the differential inertial forces arising from the plausible acceleration-deceleration forces to which the wearer might be subjected.
As shown in FIG. 2, a heart pacer 210 comprises a casing 230. Such casing is made of titanium to assure adequate inertness to the biological fluids. In a preferred embodiment, a partition 231 divides the interior of the casing into a circuitry chamber 232 and a battery chamber 233. A socket 234 is adapted to receive a plug portion of electrical conduit 11. The socket 234 is an insert within a molded organic polymeric shield 235 which protects a wire 236 extending from upper por- 4 the battery and positive grounding to the casing 230, as by having a casing of the circuitry unit in electrical contact with casing 230.
The positive pole of batteries are associated electrically with casing 236. Wires 252 and 253 from passthroughs 254 and 255 are energized respectively by wire 256 from a standard battery and by wire 257 from a supplemental battery. A negativeterminal 258 of standard battery 260 supplies current to wire 256 and thence to pass-through 254, and wire 252 and thence to circuitry means, conveniently designated as circuitry unit (1). Similarly, supplemental battery 261 supplies current to wire 257, pass-through 255, wire 253 and thence to circuitry unit 256. Thus, power from parallel batteries 260 and 261 in chamber 233 is supplied to circuitry, unit 256 in chamber 232.
Each of the pass-throughs comprises an insulating member, desirably constructed of alumina, sealed to a pin and brazed in an opening in partition 231, thus closely resembling the structure of pass-through 238. Wires 262 and 263 assure *the good electrical'connection between the positiveposts of batteries 260, 261
tion of an electrical pass-through 238 through the roof 239 of circuitry chamber 232. Any electrical signal directed to the electrical pass-through 238 is transmitted to the upper portion 237 and thence to wire 236 to socket 234, all electrical components being'anchored within plastic shield 235. The electrical pass-through metic sealing between the circuitry chamber 232 and the zone of plastic shield 235.
Within circuitry chamber 232'is a circuitry unit 250 having an output wire 251 directed to said pass-through" pin 2410. The circuitry unit 250 is energized by the combination of wire means from the negative pole of with casing 230.
"It should be noted that in a preferred embodiment, the batteries 266 and 261 are connected electrically in parallel within hermetically sealed battery chamber 233 andthat the power of two batteries is transmitted through pass- throughs 254 and 255 independently to the circuitry unit 250. Various materials, such as body fluids from cavity 16 and/or fluids within a battery might adversely affect operation of the circuitry unit 250 if any leakage occurred. However, because in such preferred embodiment circuitry chamber 232 is hermetically sealed, both from cavity 16 and from battery chamber 233, the circuitry unit 250 has appropriate protection against any leakage which might occur. Of particular importance, in all embodiments, casing 36 is hermetically sealed from cavity 16 so that the heart pacer is protected from the effects of liquids and/or gases'in cavity 16.
Particular attention is directed to the fact that battery 260 features a lithium anode 270 and an electrolyte consisting predominantly of thionyl chloride 271. Because battery 26tl features the combination of lithium anode 270 and thionyl chloride electrolyte 271, its voltage can be as high as 3.64 volts and is assuredly at least 3.3 volts during a lifetime of more than 5 years. Of particular importance,.the voltageof such lithium-thionyl chloride type battery remains substantially constant during substantially all of the life. expectancy of the battery and diminishes significantly only during a few months of theterminal period of use of the battery. The decreasin g voltage and'thus alteration of the pulse rate, provides the clue indicative of theappropriateness of a change of batteries. It is especially important that there be a procedure for detection of battery depletion. The combination of lithium anode and thionyl chloride achieves this highly significant desiderata.
In a constant rate heart pacer, the signal pulses to the heart represent only about A; of l per cent of the time during which the heart pacer is implanted. Accordingly, the battery life for a heart pacer is significantly influenced by the current drain during the 799/800s fraction of the time when no pulse is sent even though the circuitry unit must be operative. Any demand circuitry sensitive to the normal operation of the heart delivers impulses to the heart during a time fraction less than the delivery time fraction for a fixed rate heart pacer. Early types of heart pacers were based upon circuitry energized by a voltage supply of about 6 volts. Significant power was consumed by 6 volt circuitry, thereby shortening battery life.
Circuitry unit 250 is characterized by oscillator means employing complementary metal oxide semiconductor devices operable at a low voltage, so that the two lithium batteries can be connected in parallel instead of in series. Moreover, such complementary metal oxide semiconductor devices of the oscillator means permit the circuitry unit to function much of the time at a current drain which is so small that battery life can be based to a significant extent upon the dissipation of power at the signal reception zone 12 of the heart. The power consumption during the quasi-dormant portion of use is particularly significant in connection with demand pacers, in which the combination of thionyl chloride-lithium batteries and complementary metal oxide semiconductor devices are particularly advantageous.
The nature of the cardiac pacer of the present invention can be clarified by noting that the pacer consists essentially of the combination of a metal casing hermetically sealing the interior zones of the cardiac pacer from exposure to body fluids in the cavity in which the cardiac pacer is implanted, said casing being less than mm thick, and each other orthagonal dimension being less than 60 mm, such small dimensions permitting implantation without troublesome bulging of the skin adjacent the cardiac pacer, said metal casing shielding electrical components from electromagnetic interference; at least one battery in said casing, each battery generating no gas, each battery having a lithium anode and an electrolyte consisting predominantly of thionyl chloride, each battery having prolonged low impedance and constant high voltage of at least 3.3 volts during an expected life of more than 5 years, the voltage diminishing significantly only during the terminal period of use of the battery, whereby detection of battery depletion is manageable; in a preferred embodiment there are wires and pass-throughs within the casing associating at least two batteries in parallel and protecting other circuit means from interference attributable to failure of one battery while assuring the redundant reliability of parallel batteries; employing complementary metal oxide semiconductor circuit means for producing pulses adapted to stimulate the heart, said circuit means being electrically energized by current supplied by the combination of wire means from the negative pole of the battery and positive grounding to the casing of the cardiac pacer, said circuit means desirably being within a circuitry chamber within said samll casing; said complementary metal oxide semiconductors and said circuitry means consuming such a small amount of power that the battery life is more than 5 years; electrical socket means adapted to transmit to an electrical conduit said electrical pulses suitable for stimulating the heart; and said combination of casing, batteries, wires, pass-throughs, circuit means, and electrical socket means having a weight less than 100 grams and a specific gravity less than 1.7, whereby changes in acceleration or deceleration of a body having such implanted cardiac pacer impart only forces which are tolerable to tissue adjacent the cavity in which the cardiac pacer is implanted.
6 Various modifications of the invention are possible without departing from the scope of the appended claims.
It is claimed:
1. A cardiac pacer consisting essentially of the combination of:
a metal casing hermetically sealing the interior zones of the cardiac pacer from exposure to body fluids in the cavity in which the cardiac pacer is implanted, said casing being less than 20 mm thick, and each other orthagonal dimension being less than mm, such small dimensions permitting implantation without troublesome bulging of the skin adjacent the cardiac pacer, said metal casing shielding electrical components from electro-magnetic interference and constituting a grounding electrode for the cardiac pacer;
a hermetically sealed battery chamber and a hermetically sealed circuitry chamber within said casing;
a plurality of batteries in said battery chamber, there being an electrical conductor transmitting battery power from each battery to said circuitry chamber, each battery generating no gas, each battery having a lithium anode and an electrolyte consisting predominantly of thionyl chloride, each battery having prolonged low impedance and constant high voltage of at least 3.3 volts during an expected life of more than 5 years, the voltage diminishing significantly only during the terminal period of use of the battery, whereby detection of battery depletion is manageable, the positive pole of the batteries being grounded to the metal casing;
wires and pass-throughs within the casing associating at least two batteries in parallel and assuring the redundant reliability of parallel batteries;
a circuitry unit employing complementary metal oxide semiconductor circuit means for producing pulses adapted to stimulate the heart, said circuit means being electrically energized by current from said batteries, the casing of the circuit means being grounded to the casing of the heart pacer, said circuit means being within said circuitry chamber, said circuit means including an output wire, said wires and pass-throughs being electrically connected to said circuit means;
said complementary metal oxide semiconductors and said circuit means consuming such a small amount of power that the battery life is more than 5 years;
electrical socket means adapted to transmit to an electrical conduit the output from said circuit means, said electrical conduit being adapted to transmit the output from said circuit means to a signal-receiving zone of a heart, electrical passthrough means connecting said output wire to said socket means; and
said combination of casing, batteries, wires, passthroughs, circuit means, and electrical socket means having a weight less than grams and a specific gravity less than 1.7, whereby changes in acceleration or deceleration of a body having such implanted cardiac pacer impart only forces which are tolerable to tissue adjacent the cavity in which the cardiac pacer is implanted.
2. The cardiac pacer of claim 1 in which the casing consists of titanium.
3. The cardiac pacer of claim 1 in which the electrical socket means is an insert within a molded organic plastic shield.

Claims (3)

1. A CARDIAC PACER CONSISTING ESSENTIALLY OF THE COMBINATION OF: A METAL CASING HERMETICALLY SEALING THE INTERIOR ZONES OF THE CARDIAC PACER FROM EXPOSURE TO BODY FLUIDS IN THE CAVITY IN WHICH THE CARDIAC PACER IS IMPLANTED, SAID CASING BEING LESS THAN 20 MM THICK, AND EACH OTHER ORTHAGONAL DIMENSION BEING LESS THAN 60 MM, SUCH SMALL DIMENSIONS PERMITTING IMPLANTATION WITHOUT TROUBLESOME BULGING OF THE SKIN ADJACENT THE CARDIAC PACER, SAID METAL CASINFG SHIELD ING ELECTRICAL COMPONENTS FROM ELECTRO-MAGNETIC INTERFERENCE AND CONSTITUTING A GROUNDING ELECTRODE FOR THE CARDIAC PACER; A HERMETICALLY SEALED BATTERY CHAMBER AND A HERMETICALLY SEALED CIRCUITRY CHAMGER WITHIN SAID CASING; A PLURALITY OF BATTERIES IN SAID BATTERY CHAMBER, THERE BEING AN ELECTRICAL CONDUCTOR TRANSMITTING BATTERY POWER FROM EACH BATTERY TO SAID CIRCUITRY CHAMBER, EACH BATTERY GENERATING NO GAS, EACH BATTERY HAVING A LITHIUM ANODE AND AN ELECTROLYTE CONSISTING PREDOMINANTLY OF THIONYL CHLOTRIDE, EACH BATTERY HAVING PROLONGED LOW IMPEDANCE AND CONSTANT HIGH VOLTAGE OF AT LAST 3.3 VOLTS DURING AN EXPECTED LIFE OF MORE THAN 5 YEARS THE VOLTAGE DIMINISHING SIGNIFICANTLY ONLY DURING THE TERMINAL PERIOD OF USE OF THE BATTERY, WHEREBY DETECTION OF BATTERY DEPLETION IS MANAGEBLE, THE POSITIVE POLE OF THE BATTERIES BEING GROUNDED TO THE METAL CASING; WIRES AND PASS-THROUGHS WITHIN THE CASING ASSOCIATING AT LEAST TWO BATTERIES IN PARRALLEL AND ASSURING THE REDUNDANT RELIABILITY OF PARALLEL BATTERIES; A CIRCUITRY UNIT EMPLOYING COMPLEMENTARY METAL OXIDE SEMICONDUCTOR CIRCUIT MEANS FOR PRODUCING PULSES ADAPTED TO STIMULATE THE HEART, SAID CIRCUIT MEANS BEING ELECTRICALLY ENERGIZED BY CURRENT FROM SAID BATTERIES, THE CASING OF THE CIRCUIT MEANS BEING GROUNDED TO THE CASING OF THE HEART PACER, SAID CIRCUIT MEANS BEING WITH SAID CIRCUITRY CHAMBER, SAID CIRCUIT MEANS INCLUDING AN OUTPUT WIRE, SAID WIRE AND PASS-THROUGH BEING ELECTRICALLY CONNECTED TO SAID CIRCUIT MEANS; SAID COMPLEMENTARY METAL OXIDE SEMICONDUCTORS AND SAID CIRCUIT MEANS CONSUMING SUCH A SMALL AMOUNT OF POWER THAT THE BATTERY LIFE IS MORE THAN 5 YEARS; ELECTRICAL SOCKET MEANS ADAPTED TO TRANSMIT TO AN ELECTRICAL CONDUIT THE OUTPUT FROM SAID CIRCUIT MEANS SAID ELECTRICAL CONDUIT MEANS BEING ADAPTED TO TRANSMIT THE OUTPUT FROM SAID CIRCUIT MEANS TO A SIGNAL-RECEIVING ZONE OF A HEART, ELECTRIICAL PASS-THROUGH MEANS CONNECTING SAID OUTPUT WIRE TO SAID SOCKET MEANS; AND SAID COMBINATION OF CASING BATTERIES, WIRESM PASS-THROUGHS CIRCUIT MEANS, AND ELECTRICAL SOCKET MEANS HAVING A WEIGHT LESS THAN 100 GRAMS AND A SPECIFIC GRAVITY LESS THAN 1.7 WHEREBY CHANGES IN ACCELERATION OR DECELERATION OF A BODY HAVING SUCH IMPLANTED CARDIAC PACER IMPART ONLY FORCES WHICH ARE TOLERABLE TO TISSUE ADJACENT THE CAVITY IN WHICH THE CARDIAC PACER IS IMPLANTED.
2. The cardiac pacer of claim 1 in which the casing consists of titanium.
3. The cardiac pacer of claim 1 in which the electrical socket means is an insert within a molded organic plastic shield.
US574199A 1974-06-10 1975-05-02 Cardiac pacer Expired - Lifetime US3926198A (en)

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Application Number Priority Date Filing Date Title
US574199A US3926198A (en) 1974-06-10 1975-05-02 Cardiac pacer
CA226,750A CA1041609A (en) 1974-06-10 1975-05-12 Cardiac pacer
DE19752524815 DE2524815A1 (en) 1974-06-10 1975-06-04 PACEMAKER
GB24462/75A GB1491069A (en) 1974-06-10 1975-06-06 Cardiac pacers
LU72670A LU72670A1 (en) 1974-06-10 1975-06-06
BR4650/75D BR7503630A (en) 1974-06-10 1975-06-09 CARDIAC STEP BRAND
FR7517874A FR2273511A1 (en) 1974-06-10 1975-06-09 PACEMAKER
JP50070097A JPS517783A (en) 1974-06-10 1975-06-10

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US47757174A 1974-06-10 1974-06-10
US574199A US3926198A (en) 1974-06-10 1975-05-02 Cardiac pacer

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BR (1) BR7503630A (en)
CA (1) CA1041609A (en)
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FR (1) FR2273511A1 (en)
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LU (1) LU72670A1 (en)

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US7813809B2 (en) * 2004-06-10 2010-10-12 Medtronic, Inc. Implantable pulse generator for providing functional and/or therapeutic stimulation of muscles and/or nerves and/or central nervous system tissue
US8165692B2 (en) 2004-06-10 2012-04-24 Medtronic Urinary Solutions, Inc. Implantable pulse generator power management
US8195304B2 (en) 2004-06-10 2012-06-05 Medtronic Urinary Solutions, Inc. Implantable systems and methods for acquisition and processing of electrical signals
US8467875B2 (en) 2004-02-12 2013-06-18 Medtronic, Inc. Stimulation of dorsal genital nerves to treat urologic dysfunctions
US9162072B2 (en) 2004-04-30 2015-10-20 Medtronic, Inc. Implantable medical device with lubricious material
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US9308382B2 (en) 2004-06-10 2016-04-12 Medtronic Urinary Solutions, Inc. Implantable pulse generator systems and methods for providing functional and/or therapeutic stimulation of muscles and/or nerves and/or central nervous system tissue
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Publication number Priority date Publication date Assignee Title
US4010759A (en) * 1975-08-29 1977-03-08 Vitatron Medical B.V. Insulated, corrosion resistant medical electronic devices and method for producing same
US4038991A (en) * 1976-03-15 1977-08-02 Arco Medical Products Company Cardiac pacer with rate limiting means
US4013081A (en) * 1976-04-19 1977-03-22 Arco Medical Products Company Pediatric cardiac pacer system
US4256115A (en) * 1976-12-20 1981-03-17 American Technology, Inc. Leadless cardiac pacer
US4127134A (en) * 1977-04-11 1978-11-28 Cordis Corporation Gas-absorbing pacer and method of fabrication
US4254775A (en) * 1979-07-02 1981-03-10 Mieczyslaw Mirowski Implantable defibrillator and package therefor
US4399819A (en) * 1981-12-21 1983-08-23 Telectronics Pty. Ltd. Heart pacer mechanical construction
US4869251A (en) * 1986-07-15 1989-09-26 Siemens Aktiengesellschaft Implantable heart pacemaker with a sensor for inertial and/or rotational movements of the user
US20050119707A1 (en) * 1990-04-25 2005-06-02 Cardiac Pacemakers, Inc. Subcutaneous cardiac rhythm management
US6999814B2 (en) 1990-04-25 2006-02-14 Cardiac Pacemakers, Inc. Implantable intravenous cardiac stimulation system with pulse generator housing serving as optional additional electrode
US7522959B2 (en) 1990-04-25 2009-04-21 Cardiac Pacemakers, Inc. Subcutaneous cardiac rhythm management
US5385574A (en) * 1990-04-25 1995-01-31 Cardiac Pacemakers, Inc. Implantable intravenous cardiac stimulation system with pulse generator housing serving as optional additional electrode
US5439482A (en) * 1992-04-07 1995-08-08 Angeion Corporation Prophylactic implantable cardioverter-defibrillator
US5674248A (en) * 1995-01-23 1997-10-07 Angeion Corporation Staged energy concentration for an implantable biomedical device
US5814091A (en) * 1996-03-26 1998-09-29 Pacesetter Ab Active medical implant having a hermetically sealed capsule and method for making same
WO1999005750A1 (en) * 1997-07-25 1999-02-04 Cardiac Pacemakers, Inc. Battery system for implantable medical device
US6238813B1 (en) 1997-07-25 2001-05-29 Cardiac Pacemakers, Inc. Battery system for implantable medical device
WO1999057871A1 (en) * 1998-04-22 1999-11-11 Increa Oy Radiophone
US6192277B1 (en) 1999-07-06 2001-02-20 Pacesetter, Inc. Implantable device with bevel gear actuation for lead retention and actuation
US6736770B2 (en) 2000-08-25 2004-05-18 Cochlear Limited Implantable medical device comprising an hermetically sealed housing
US20020051550A1 (en) * 2000-08-25 2002-05-02 Hans Leysieffer Implantable hermetically sealed housing for an implantable medical device and process for producing the same
US8086313B2 (en) 2002-12-09 2011-12-27 Medtronic, Inc. Implantable medical device with anti-infection agent
US8457744B2 (en) 2002-12-09 2013-06-04 Medtronic, Inc. Low-profile implantable medical device
US7529586B2 (en) * 2002-12-09 2009-05-05 Medtronic, Inc. Concavity of an implantable medical device
US7596408B2 (en) 2002-12-09 2009-09-29 Medtronic, Inc. Implantable medical device with anti-infection agent
US20060184220A1 (en) * 2003-05-16 2006-08-17 Medtronic, Inc. Explantation of implantable medical device
US8467875B2 (en) 2004-02-12 2013-06-18 Medtronic, Inc. Stimulation of dorsal genital nerves to treat urologic dysfunctions
US9162072B2 (en) 2004-04-30 2015-10-20 Medtronic, Inc. Implantable medical device with lubricious material
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US9724526B2 (en) 2004-06-10 2017-08-08 Medtronic Urinary Solutions, Inc. Implantable pulse generator systems and methods for operating the same
US9216294B2 (en) 2004-06-10 2015-12-22 Medtronic Urinary Solutions, Inc. Systems and methods for clinician control of stimulation systems
US9308382B2 (en) 2004-06-10 2016-04-12 Medtronic Urinary Solutions, Inc. Implantable pulse generator systems and methods for providing functional and/or therapeutic stimulation of muscles and/or nerves and/or central nervous system tissue
US9205255B2 (en) 2004-06-10 2015-12-08 Medtronic Urinary Solutions, Inc. Implantable pulse generator systems and methods for providing functional and/or therapeutic stimulation of muscles and/or nerves and/or central nervous system tissue
US7761167B2 (en) 2004-06-10 2010-07-20 Medtronic Urinary Solutions, Inc. Systems and methods for clinician control of stimulation systems
US8706252B2 (en) 2004-06-10 2014-04-22 Medtronic, Inc. Systems and methods for clinician control of stimulation system
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US10434320B2 (en) 2004-06-10 2019-10-08 Medtronic Urinary Solutions, Inc. Implantable pulse generator systems and methods for providing functional and/or therapeutic stimulation of muscles and/or nerves and/or central nervous system tissue
US8165692B2 (en) 2004-06-10 2012-04-24 Medtronic Urinary Solutions, Inc. Implantable pulse generator power management
US7813809B2 (en) * 2004-06-10 2010-10-12 Medtronic, Inc. Implantable pulse generator for providing functional and/or therapeutic stimulation of muscles and/or nerves and/or central nervous system tissue
US20060276842A1 (en) * 2005-06-01 2006-12-07 Advanced Bionics Corporation Implantable microstimulator with external electrodes disposed on a film substrate and methods of manufacture and use
US7957805B2 (en) * 2005-06-01 2011-06-07 Boston Scientific Neuromodulation Corporation Implantable microstimulator with external electrodes disposed on a film substrate and methods of manufacture and use
US9504402B2 (en) 2006-04-28 2016-11-29 Medtronic, Inc. Cranial implant
US20080186691A1 (en) * 2006-04-28 2008-08-07 Mertz John C Implantable medical device housing reinforcement
US9480846B2 (en) 2006-05-17 2016-11-01 Medtronic Urinary Solutions, Inc. Systems and methods for patient control of stimulation systems
US10322287B2 (en) 2006-05-17 2019-06-18 Medtronic Urinary Solutions, Inc. Systems and methods for patient control of stimulation systems
US9393432B2 (en) 2008-10-31 2016-07-19 Medtronic, Inc. Non-hermetic direct current interconnect

Also Published As

Publication number Publication date
GB1491069A (en) 1977-11-09
FR2273511A1 (en) 1976-01-02
JPS517783A (en) 1976-01-22
CA1041609A (en) 1978-10-31
LU72670A1 (en) 1975-10-08
DE2524815A1 (en) 1976-01-02
BR7503630A (en) 1976-06-22

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