EP0000989B1 - Bedarfschrittmacher mit einer verminderten Erholungszeit - Google Patents

Bedarfschrittmacher mit einer verminderten Erholungszeit Download PDF

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Publication number
EP0000989B1
EP0000989B1 EP19780300243 EP78300243A EP0000989B1 EP 0000989 B1 EP0000989 B1 EP 0000989B1 EP 19780300243 EP19780300243 EP 19780300243 EP 78300243 A EP78300243 A EP 78300243A EP 0000989 B1 EP0000989 B1 EP 0000989B1
Authority
EP
European Patent Office
Prior art keywords
output
pulse
counter
bistable
stimulating
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
EP19780300243
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English (en)
French (fr)
Other versions
EP0000989A1 (de
Inventor
Dennis Digby
Kenneth Roy Allen
Alan Coombes
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
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Filing date
Publication date
Priority claimed from US05/917,131 external-priority patent/US4170999A/en
Application filed by Biotronik Mess und Therapiegeraete GmbH and Co filed Critical Biotronik Mess und Therapiegeraete GmbH and Co
Publication of EP0000989A1 publication Critical patent/EP0000989A1/de
Application granted granted Critical
Publication of EP0000989B1 publication Critical patent/EP0000989B1/de
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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
    • A61N1/362—Heart stimulators
    • A61N1/365—Heart stimulators controlled by a physiological parameter, e.g. heart potential

Definitions

  • This invention relates to implantable body function control apparatus and particularly cardiac pacemakers.
  • Pacemakers for generating artificial stimulating pulses for the heart, and which may or may not be implanted in the body, are well-known. Pacemakers can be classified into demand and non-demand types. A demand pacemaker only issues an artificial pulse if the heart does not produce its own satisfactory natural beat, whereas a non-demand pacemakers issues artificial stimulating pulses without regard to the presence or absence of a natural beat.
  • a demand pacemaker normally includes an input amplifier for receiving and amplifying electrical signals from the heart (which signals might result from either a natural beat or an artificial pulse which has just been generated by the pacemaker), a pacemaker control circuitry which receives the amplified signals and which causes a new artificial stimulating pulse to be generated (for transmission to the heart) only if the amplified signals, or lack thereof, show that an artificial stimulating pulse is required by the heart (i.e. on demand), and an output amplifier which receives and amplifies the artificial pulses generated by the control circuitry, for passage to the heart.
  • pacemaker control circuitry as described above are available. Some function on an analog basis to produce the accurately- timed artificial stimulating pulses, whereas several recent designs employ digital circuitry.
  • the input amplifier requires a high sensitivity and it has been found difficult to design an adequate amplifier that does not saturate for too long a period when an artificial pulse is transmitted to the heart by the output amplifier (this pulse being detected by the input amplifier).
  • the load which is driven by the output amplifier (the electrodes and the heart tissue itself) has capacitive properties and these, coupled with the capacitive components normally present in the output amplifier, can act to extend the length of any artificial pulse transmitted to the heart. Even if a sharp artificial pulse is generated by the pacemaker control circuitry, the capacitive effects at the output cause the trailing edge of the pulse to be extended so as to give a somewhat exponential decay back to zero. This extension of the output pulse is reflected at the input amplifier by increasing the length of time for which the latter remains saturated.
  • the present invention is concerned with alleviating this problem, so as to avoid these capacitive effects from increasing the saturation period of the input amplifier unnecessarily.
  • This is accomplished, in this invention, by arranging for electrical energy to be fed into the pacemaker circuitry, at an appropriate moment after an artificial stimulating pulse is generated, in opposition to the energy stored by the capacitive components responsible for the extension of the artificial pulse. This has the effect of shorting these capacitive components, thus providing a much sharper falling edge for the output pulse and hence reducing the period of time spent by the input amplifier in saturation.
  • German specification 2520729A describes a method for shortening the decay time of pulses applied to the heart although the technique employed differs from that used in the present invention.
  • the pacemaker control circuitry includes a pulse generator for providing an artificial stimulating pulse, and means for resetting the pulse generator controlled either by an artificial pulse just generated or by a signal representative of a natural heart beat, so that the next artificial pulse is generated in timed relationship with the previous artificial pulse and only on demand.
  • the additional transistor in the output amplifier can be arranged to be controlled by the reset provided to the pulse generator.
  • the reset determines the pulse width of the artificial pulse and by causing the additional transistor to compensate for the capacitive effects once the reset is applied, the sharp trailing edge of the artificial pulse is substantially maintained. A slow decay after the reset is applied is thus avoided, as therefore is an extension of the input amplifier saturation time.
  • the input amplifier is represented by section 1
  • the pacemaker control circuitry which generates artificial stimulating pulses on demand is represented by section 2
  • the output amplifier is represented by section 3.
  • the pacemaker load i.e. the electrodes and the body tissue therebetween, is illustrated by a resistive/capacitive combination within a further section, section 4.
  • Sections 1, 2, and 3 can be considered as representing a basic demand pacemaker.
  • Oscillator 5 free runs and the particular artificial stimulating pulse rate appropriate to the patient is selected by counter 6 (the Ox output stage) for transmission to the output amplifier of section 3.
  • counter 6 the Ox output stage
  • a reset circuit 7 for counter 6 (consisting of an OR gate followed by a delay D) is activated so that the artificial pulse count is not reached and no artificial pulse is generated. If no such natural beat is detected, the artificial pulse count is reached, and an artificial pulse is transmitted to the heart (section 4) by means of the output amplifier (section 3).
  • the pulse width is determined by the delay D generated in the reset circuit 7 - the counter 6 being reset at the termination of this delay.
  • the pacemaker circuitry additionally includes a D flip-flop 10 which receives, at its clock input via an inverter 11, the reset pulse for counter 6.
  • the reset input for flip-flop 10 is supplied by the counter 6 output, its D input is tied to the positive supply rail and its Q output clocks a second D flip-flop 12.
  • Flip-flop 12 is reset by a system clock (derived from an appropriate stage Qy of counter 6) and has its D input tied to the positive supply rail.
  • the Q output of flip-flop 12 controls the gate of a field effect transistor 13.
  • the transistor 13 drain and source terminals are connected respectively to the positive supply rail, and via a resistor 14, to the output amplifier, adjacent output capacitor 8.

Claims (4)

1. Vorrichtung für die Herzstimulation vom Demand-Typ mit
a) Elektrodenmitteln zum Übermitteln von Stimulationsimpulsen zum Herzen;
b) einer Ausgangsverstärkerstufe (3) zum Erzeugen der Stimulationsimpulse für das Herz, wobei die Ausgangsstufe einen Ausgangskondensator aufweist, der mit den Elektrodenmitteln verbunden ist, und die Ausgangsstufe eine Ausgangsimpedanz aufweist, welche ein Erholungsintervall vorsieht, das nach jeder Erzeugung eines Stimulationsimpulses, im wesentlichen durch die Ansammlung und die anschließende Verzehrung der Ladung des genannten Ausgangskondensators (8), hervorgerufen wird;
c) Eingangsverstärkermitteln (1), welche auf Signale der Ausgangsstufe (3) und natürlich auftretende Herzimpulssignale hin ein Steuersignal mit Bezug auf die Erzeugung des nächstfolgenden Stimulationsimpulses hervorrufen; und
d) logischen Mitteln (2), welche auf das Steuersignal ansprechen, um selektiv den Ausgangsverstärker (3) zur Erzeugung von Stimulationsimpulsen aufgrund der Bedarfsschrittmacherkriterien zu aktivieren;

dadurch gekennzeichnet, daß die Mittel Verkürzung des Erholungsintervalls umfassen:
(i) erste bistabile Mittel (10), welche durch die logischen Mittel (2) zu einer ersten vorbestimmten Zeit nach jeder selektiven Aktivierung in einen ersten aktivierten Ausgangszustand gesetzt werden;
(ii) zweite bistabile Mittel (12), welche in einen zweiten aktivierenden Ausgangszustand durch den Aktivierungszustand der ersten bistabilen Mittel (10) getaktet werden, wobei der aktivierende Ausgangszustand der zweiten bistabilen Mittel (12) durch die logischen Mittel (2) nach einer zweiten vorgegebenen Zeit beendet wird und die zweite Zeitdauer ein verkürztes Erholungsintervall der Ausgangsstufe festlegt, und
(iii) Transistormittel (13), welche auf die zweiten bistabilen Mittel (12) ansprechen und während der zweiten Zeit aktiviert werden, um die Ladung des Ausgangskondensators (8) zu verzehren und dadurch ein verkürztes Erholungsintervall für die Ausgangsstufe (3) festzulegen.
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die logischen Mittel (2) einen Oszillator (5), Zählmittel (6) zum Zählen der Impulse des Oszillators (5) und Verzögerungsmittel (7) enthalten, welche durch das Steuersignal oder durch den ersten vorbestimmten Zählerstand (Qx) bei dem Zähler (6) aktiviert werden, um einen Ausgangsimpuls mit einer vorbestimmten Verzögerungszeit nach der Aktivierung zu erzeugen, wobei dei ersten bistabilen Mittel (10) durch den ersten vorbestimmten Zählerstand (Qx) des Zählers (6) zurückgesetzt werden und in ihren ersten Aktivierungsausgangszustand durch den Ausgangsimpuls über die Verzögerungsmittel (7) getaktet werden, und daß die zweiten bistabilen Mittel (12) durch einen zweiten vorbestimmten Zählerstand (Qy) später als durch den ersten Zählerstand (Qx) bei den Zählermitteln (6) zurückgesetzt werden.
3. Vorrichtung nach Anspruch 2, dadurch gekennzeichnet, daß die Zählermittel (6) durch jeden Ausgangsimpuls der Verzögerungsmittel (7) zurückgesetzt werden.
4. Vorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß die bistabilen Mittel (10, 12) durch D-Flip-Flops gebildet werden, deren D-Eingänge jeweils an eine positive Versorgungsspannung angeschlossen sind, wobie das Ausgangssignal der ersten Flip-Flops (10) das Q-Ausgangssignal und das Ausgangssignal des zweiten Flip-Flops (12) das O-Ausgangssignal bildet.
EP19780300243 1977-08-19 1978-08-03 Bedarfschrittmacher mit einer verminderten Erholungszeit Expired EP0000989B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB3491577 1977-08-19
GB3491577 1977-08-19
US05/917,131 US4170999A (en) 1977-08-19 1978-06-19 Demand pacer having reduced recovery time
US917131 1986-10-09

Publications (2)

Publication Number Publication Date
EP0000989A1 EP0000989A1 (de) 1979-03-07
EP0000989B1 true EP0000989B1 (de) 1981-11-25

Family

ID=26262491

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19780300243 Expired EP0000989B1 (de) 1977-08-19 1978-08-03 Bedarfschrittmacher mit einer verminderten Erholungszeit

Country Status (4)

Country Link
EP (1) EP0000989B1 (de)
AU (1) AU3895578A (de)
CA (1) CA1098590A (de)
DE (1) DE2861354D1 (de)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4476868A (en) * 1978-11-06 1984-10-16 Medtronic, Inc. Body stimulator output circuit
FR2440198A1 (fr) * 1978-11-06 1980-05-30 Medtronic Inc Stimulateur implantable
WO1982003787A1 (en) * 1981-05-04 1982-11-11 Nettelhorst Herwig Pacemaker
GB8612659D0 (en) * 1986-05-23 1986-07-02 Coventry City Council Cardiac pacemaker circuit
DE4231603A1 (de) * 1992-09-17 1994-03-24 Biotronik Mess & Therapieg Herzschrittmachersystem
DE19615159C1 (de) * 1996-04-17 1997-10-16 Medtronic Inc Herzschrittmacher
FI119626B (fi) 2007-07-11 2009-01-30 Wd Racing Oy Vulkanointimuotin ilmanpoistoventtiili

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3563247A (en) * 1968-03-14 1971-02-16 Gen Electric Bidirectional heart stimulator
US3835865A (en) * 1970-07-10 1974-09-17 Gen Electric Body organ stimulator
DE2342030A1 (de) * 1973-08-20 1975-03-27 Siemens Ag Elektrischer herzschrittmacher
CS167779B1 (de) * 1974-05-16 1976-05-28
NL7700427A (nl) * 1976-03-03 1977-09-06 Arco Med Prod Co Inplanteerbare digitale hartgangmaker, welke voorzien is van extern kiesbare bedrijfspara- meters.
DE2619001C2 (de) * 1976-04-29 1985-10-31 Siemens AG, 1000 Berlin und 8000 München Herzschrittmacher

Also Published As

Publication number Publication date
EP0000989A1 (de) 1979-03-07
DE2861354D1 (en) 1982-01-28
AU3895578A (en) 1980-02-21
CA1098590A (en) 1981-03-31

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