EP0000984B1 - Stimulateur programmable avec amplificateur a gain variable - Google Patents

Stimulateur programmable avec amplificateur a gain variable Download PDF

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Publication number
EP0000984B1
EP0000984B1 EP19780300237 EP78300237A EP0000984B1 EP 0000984 B1 EP0000984 B1 EP 0000984B1 EP 19780300237 EP19780300237 EP 19780300237 EP 78300237 A EP78300237 A EP 78300237A EP 0000984 B1 EP0000984 B1 EP 0000984B1
Authority
EP
European Patent Office
Prior art keywords
pacemaker
signals
heart
input amplifier
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19780300237
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German (de)
English (en)
Other versions
EP0000984A1 (fr
Inventor
John Walter Keller
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Biotronik SE and Co KG
Original Assignee
Biotronik Mess und Therapiegeraete GmbH and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US05/917,142 external-priority patent/US4202342A/en
Application filed by Biotronik Mess und Therapiegeraete GmbH and Co filed Critical Biotronik Mess und Therapiegeraete GmbH and Co
Publication of EP0000984A1 publication Critical patent/EP0000984A1/fr
Application granted granted Critical
Publication of EP0000984B1 publication Critical patent/EP0000984B1/fr
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372—Arrangements in connection with the implantation of stimulators
    • A61N1/37211—Means for communicating with stimulators

Definitions

  • This invention relates to cardiac pacemakers.
  • Pacemakers for generating artificial stimulating pulses for the heart, and which may be implanted in the body, are well known.
  • the electrical circuitry for such pacemakers was of analog design, but in recent years digital circuitry has been also employed.
  • a digital approach to pacemakers has led to the evolution of programmable pacemakers-pacemakers having parameters such as pulse rates which are adjustable (programmable) once the pacemaker has been implanted.
  • the programs can be changed from outside the patient's body by appropriate signal transmission to the implanted pacemaker and without surgery.
  • Programmable pacemakers are described in for instance, British Specifications 1,385,954 and 1,398,875.
  • Such pacemakers have circuitry to detect and decode signals transmitted outside the body and alter the program accordingly.
  • pacemakers are of the demand type- that is they only supply a stimulating pulse to the heart when a natural heart beat is absent. To accomplish this, demand pacemakers have means for sensing the presence or absence of natural heat beats and for actuating the stimulating pulse as appropriate.
  • Demand pacemakers normally have an input amplifier which receives the electrical signals detected at the heart, and the amplified signals are then employed to control the demand function of the pacemaker.
  • signals provided by the input amplifier are employed to inhibit any artificial pulse being generated by the pacemaker: the absence of such signals being taken by the pacemaker as indicating the absence of a normal heart beat and causing artificial stimulating pulses to be generated.
  • Pacemakers are implanted in the body for a period of years, and during that time various parameters can change causing the effective signals supplied by the input amplifier to change in magnitude. Typical of such parameters is an increase in impedance of the body tissue as "seen" by the pacing electrode. But most prevalent is the wide range of electrode placement effectiveness which can result in not only very large but very small signals.
  • U.S. Patent 4,049,004 describes an implantable cardiac pacemaker with a number of externally programmable pacemaker functions including the sensitivity of the pacemaker response to signals at the heart.
  • the pacemaker includes an R-wave input amplifier constructed as an operational amplifier whose output is employed for resetting the stimulating pulse generator, thereby giving the pacemaker a demand capability.
  • the output of the operational amplifier is supplied to a field effect transistor whose switching threshold is varied from a master parameter control.
  • the latter is a memory store whose contents may be varied after implantation from a remote source of programming signals. This arrangement has no effect on the overall amplification provided to the signal supplied to the R-wave amplifier and can cause erroneous control of the pacemaker in certain operational states.
  • the field effect transistor can cut off the signal which should be employed to reset the pulse generator.
  • a pacemaker circuit which enables the signal supplied by the input amplifier to be changed after implantation and which does enable, for example, input signals of small magnitude to be handled at increased amplification or without the risk of cutting off the signal to be employed for resetting the pulse generator. This has been accomplished by providing different levels of attenuation for the signal supplied to the input amplifier and by selecting the desired attenuation by means of a program held in a pacemaker memory store.
  • an implantable cardiac pacemaker having a pacemaker function programmably alterable from a remote source of pacemaker function programming signals, comprising pulse generating means (1, 2, 3, 4,) for periodically issuing stimulating pulses, an input amplifier (12) for sensing signals at the heart and for resetting said generating means in response to a sensed signal, and memory means (18) responsive to signals from said remote source for varying the signal provided by the input amplifier for resetting said pulse generating means, characterised in that said varying means comprises a potential dividing network (11, 14) provided with an intermediate tap connected to the input of said input amplifier (12), means (13) connecting one extremity of said network to sense signals at the heart, and means (15, 16, 17) connected to apply to the other extremity of said network a potential controlled by an output signal of said memory means (18) for controlling the magnitude of the sensed heart signal applied to the input amplifier.
  • the pacemaker comprises an oscillator 1 which clocks a ripple counter 2.
  • Various outputs from the ripple counter are combined as is known in the art by means of logic gates (not shown) to provide four output lines 3.
  • the oscillator frequency and combination of ripple counter outputs are selected so that the four output lines 3 provide, respectively, body stimulation pulses at four different frequencies (e.g. 50, 60, 70, 80 pulses per minute).
  • the four output lines 3 are supplied to a rate decoder 4 provided with two input control lines 5.
  • the logic levels on lines 5 can be employed to select uniquely one from four of the four lines 3 and transmit the selected pulse frequency on line 6.
  • Line 6 is connected to an output amplifier 7 which in turn is connected to a connection 8 which leads to an active stimulating pulse electrode (not shown) disposed in or on the heart.
  • Line 6 also provides one input to an OR gate 9.
  • OR gate 9 The output of OR gate 9 is supplied to a delay unit 10 whose output is employed to reset counter 2.
  • the delay generated by delay unit 10 sets the pulse width for each artificial stimulating pulse which is transmitted on output line 6.
  • the active electrode disposed in or on the heart feeds back the electrical signals detected at the heart (arising from an artificial stimulating pulse or a natural heart beat) to the pacemaker via a resistor 11 (R1).
  • the output of resistor R 1 is connected to an input amplifier 12 which in turn supplies a second input to OR gate 9.
  • the feedback loop for such signals through the active electrode is illustrated by means of line 13.
  • a second resistor 14 Connected to input amplifier 12 is a second resistor 14 (R 2 ), which is connected via a capacitor 15 to the drain of a field effect transistor 16, the source of which is connected to Vpp.
  • the gate of the transistor 16 is controlled by a control line 17 which, as with control lines 5, extends from a pacemaker program store 18.
  • the program store 18 is arranged to hold, as a pacemaker program, a series of binary values for supply on the control lines 5 and 17.
  • a receiver/decoder 19 is arranged to receive and decode data signals transmitted from outside the patient's body to the implanted pacemaker, and to employ the decoded signals for changing a pacemaker program held in program store 18.
  • the data signals may be transmitted to the receiver/decoder 19 by any suitable means, but preferably we employ data signals transmitted by tone burst modulation (pulse width modulation of a carrier frequency).
  • the pacemaker operates as follows. A program is entered and held in the program store 18 and the binary levels on control lines 5 determine which one of the four outputs 3 derived from counter 2 is passed by rate decoder 4 onto output line 6.
  • the counter 2 In the absence of natural heart beats, the counter 2 successively generates a series of artificial pulses at the selected rate and these are supplied to the heart via output amplifier 7. Each artificial pulse causes a reset of counter 2 via OR gate 9 and delay 10 to enable the count for the next artificial pulse to commence.
  • the pacemaker operates in a normal demand mode-issuing artificial pulses only when demanded by the heart. It is of no consequence if the reset initiated by a natural heart beat arrives just as an artificial pulse is generated, since the natural beat and the stimulating pulse will essentially coincide.
  • a "0" is held in the program store 18 and this causes attenuation of the input signal to amplifier 12.
  • the gain of amplifier 12 and other parameters of the circuit are set such that the attenuation is acceptable and that the attenuated signal received is still of sufficient magnitude to carry out its necessary function of controlling the demand function of the pacemaker.
  • the program is changed to "1", to cause R 2 to float and remove attenuation of the input signal.

Landscapes

  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Electrotherapy Devices (AREA)

Claims (3)

1. Stimulateur cardiaque implantable possédant une fonction de stimulateur qui peut être modifiée par programmation à partir d'une source éloignée de signaux de programmation de fonction de stimulateur, comprenant un moyen (1, 2, 3, 4) générateur d'impulsions qui délivre périodiquement des impulsions de stimulation, un amplificateur d'entrée (12) qui détecte des signaux au niveau du coeur et qui repositionne ledit moyen générateur en réponse à un signal détecté, et un moyen de variation comportant un moyen de mémorisation (18) qui répond à des signaux en provenance de ladite source éloignée en faisant varier le signal fourni par l'amplificateur d'entrée (12) pour re- positionner ledit moyen générateur d'impulsions, caractérisé en ce que ledit moyen de variation comprend un réseau diviseur de tension (11, 14) doté d'une prise intermédiaire connectée à l'entrée dudit amplificateur d'entrée (12), un moyen (13) qui connecte une première extrémité dudit réseau afin de détecter des signaux au niveau du coeur, et un moyen (15, 16, 17) connecté de façon à appliquer à l'autre extrémité dudit réseau un potentiel commandé par un signal de sortie dudit moyen de mémorisation (18) de façon à commander l'amplitude du signal cardiaque détecté qui est appliqué à l'amplificateur d'entrée.
2. Stimulateur cardiaque implantable selon la revendication 1, caractérisé en ce que ledit moyen connecté de façon à appliquer un potentiel comprend une source de tension (VDD), un condensateur (15) connecté par un premier de ses côtés à ladite autre extrémité dudit réseau, et un moyen de commutation (16) disposé entre ladite source (Vpp) et l'autre côté dudit condensateur (X), ledit moyen de commutation (16) s'activant en réponse au signal de sortie dudit moyen de mémorisation.
3. Stimulateur cardiaque implantable selon la revendication 2, caractérisé en ce que ledit moyen de commutation (16) comprend un transistor à effet de champ dont l'électrode de grille reçoit (17) ledit signal de sortie dudit moyen de mémorisation.
EP19780300237 1977-08-19 1978-08-03 Stimulateur programmable avec amplificateur a gain variable Expired EP0000984B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB3491777 1977-08-19
GB3491777 1977-08-19
US917142 1978-06-19
US05/917,142 US4202342A (en) 1977-08-19 1978-06-19 Programmable pacer with variable amplifier sensitivity and pacing rate

Publications (2)

Publication Number Publication Date
EP0000984A1 EP0000984A1 (fr) 1979-03-07
EP0000984B1 true EP0000984B1 (fr) 1983-05-11

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19780300237 Expired EP0000984B1 (fr) 1977-08-19 1978-08-03 Stimulateur programmable avec amplificateur a gain variable

Country Status (4)

Country Link
EP (1) EP0000984B1 (fr)
AU (1) AU3895778A (fr)
CA (1) CA1098591A (fr)
DE (1) DE2862246D1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2440199A1 (fr) * 1978-11-06 1980-05-30 Medtronic Inc Stimulateur cardiaque a la demande
US5080096A (en) * 1990-07-06 1992-01-14 Medtronic, Inc. Method and apparatus for accessing a nonvolatile memory
EP3351225B1 (fr) 2013-09-19 2021-12-29 The Procter & Gamble Company Noyaux absorbants ayant des zones exemptes de matériau

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3830242A (en) * 1970-06-18 1974-08-20 Medtronic Inc Rate controller and checker for a cardiac pacer pulse generator means
NL7700427A (nl) * 1976-03-03 1977-09-06 Arco Med Prod Co Inplanteerbare digitale hartgangmaker, welke voorzien is van extern kiesbare bedrijfspara- meters.

Also Published As

Publication number Publication date
AU3895778A (en) 1980-02-21
CA1098591A (fr) 1981-03-31
EP0000984A1 (fr) 1979-03-07
DE2862246D1 (en) 1983-06-16

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