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EP0000987B1 - Bedarfschrittmacher mit programmierbarer Frequenz-Hysteresis - Google Patents

Bedarfschrittmacher mit programmierbarer Frequenz-Hysteresis Download PDF

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Publication number
EP0000987B1
EP0000987B1 EP78300241A EP78300241A EP0000987B1 EP 0000987 B1 EP0000987 B1 EP 0000987B1 EP 78300241 A EP78300241 A EP 78300241A EP 78300241 A EP78300241 A EP 78300241A EP 0000987 B1 EP0000987 B1 EP 0000987B1
Authority
EP
European Patent Office
Prior art keywords
rate
pulse
rates
responsive
pulses
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
EP78300241A
Other languages
English (en)
French (fr)
Other versions
EP0000987A1 (de
Inventor
Dennis Digby
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 US05/917,141 external-priority patent/US4169480A/en
Application filed by Biotronik Mess und Therapiegeraete GmbH and Co filed Critical Biotronik Mess und Therapiegeraete GmbH and Co
Publication of EP0000987A1 publication Critical patent/EP0000987A1/de
Application granted granted Critical
Publication of EP0000987B1 publication Critical patent/EP0000987B1/de
Expired legal-status Critical Current

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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
    • A61N1/37252—Details of algorithms or data aspects of communication system, e.g. handshaking, transmitting specific data or segmenting data
    • A61N1/37264—Changing the program; Upgrading firmware

Definitions

  • This invention relates to demand cardiac pacemakers having a programmable rate hysteresis function.
  • 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 heart beats and for actuating the stimulating pulse as appropriate.
  • a demand pacemaker It is desirable with a demand pacemaker that the stimulating pulses are issued only when really needed by the heart, and that the latter is given the opportunity of functioning as naturally as possible.
  • One approach to providing this desirable property has been to provide the implanted pacemaker with a fixed hysteresis function for the pacing rate, so that, after each natural heart beat detected which inhibits a stimulating pulse, a slight delay occurs before the next stimulating pulse is generated.
  • Hysteresis is therefore the characteristic of a pacemaker whereby the period of time from a natural heart beat to the next pacing pulse is longer than the period between two successive pacing pulses.
  • This hysteresis which essentially involves the pacemaker switching over to issuing one stimulating pulse at a slower rate after one or more natural beats has arisen, is of particular use in that it avoids competition between natural heart beats and artificial stimulating pulses, and hence reduces current drain on the pacemaker. It is desirable to allow as many natural beats to arise normally without any stimulation of the heart being provided: by supplying a hysteresis function, a greater opportunity is being given for the natural beats to continue without an artificial pulse being generated.
  • a pacemaker with an optional hysteresis function has been described in U.S. Patent 3,999,557.
  • This pacemaker has different standby (monitoring) and pacing rates (giving a rate hysteresis function) and circuitry for selectively rendering these rates identical (giving a normal demand pacemaker function).
  • These rates are dictated by the charging and discharging of two capacitors under the control of a memory store in the form of a flip-flop.
  • the latter may be remotely programmed (e.g. when the pacemaker is implanted) by the closing of a reed switch.
  • the pacemaker as described represents an analog approach to the control of the pulse rates and does not suggest the possibility of selecting one of a plurality of differently programmable rate hysteresis functions.
  • a demand cardiac pacemaker having a rate hysteresis function which may be pro- grammably stored therein from a remote programming means so that it optionally operates in said mode when desired, comprising:
  • the pacemaker comprises an oscillator 1 which clocks a counter 2.
  • the counter provides two outputs, Ox which can be considered as issuing pulses at "slow" tissue stimulation pulse rate (e.g. 60 pulses per minute), and Qy which can be considered as issuing pulses at a "normal” tissue stimulation pulse rate (e.g. 70 pulses per minute).
  • the Qy and Ox outputs supply an input, respectively, to AND gates 3 and 4, whose outputs are provided to an OR gate 5.
  • the output of the latter is supplied to an output amplifier, 6, to the clock input of a D-flip-flop 7, and to an OR gate 8.
  • the latter output supplies a delay 9, the output of which is connected to the reset of counter 2.
  • the output amplifier 6 provides amplified tissue stimulating pulses to a connection 10 for coupling to an electrode leading to the heart.
  • An input amplifier 11 receives electrical signals detected at the heart (e.g. arising from a natural heart beat) and supplies these to a second input of OR gate 8.
  • a receiver/decoder 12 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 13.
  • the receiver/decoder 12 and store 13 have been depicted very simply and as providing an output for controlling only the hysteresis function. In. practice it would be desirable to make these features much more sophisticated so that the program store is employed to provide a varying control for several different pacemaker parameters (e.g. pulse rate, pulse width, and varying amounts-of hysteresis with various programs, depending upon past history of spontaneous beats).
  • the data signals may be transmitted to the receiver/decoder 12 by any suitable means, but preferably we employ data signals transmitted by tone burst modulation (a carrier frequency being pulse width modulated).
  • the output supplied by program store 13 is a single "bit" of binary information, which is provided on line 14 to an AND gate 15.
  • a second input to AND gate 15 is supplied from input amplifier 11.
  • the output of AND gate 15 is connected to the reset of flip-flop 7.
  • the D-input to flip-flop 7 is supplied from the positive supply rail.
  • the Q and Q outputs of flip-flop 7 are supplied as inputs to AND gates 3 and 4, respectively.
  • the pacemaker functions as follows. Assume initially that the hysteresis function has not been selected. This will be provided by storing a "0" in store 13 so as to prevent any reset for flip-flop 7 via line 14 and AND gate 15 occurring. Assume that, when switched on initially, the counter 2 has issued a count via OR gate 5, and that flip-flop 7 is in the "1" state with its Q output high.
  • oscillator 1 clocks counter 2 and the Qy "normal" pulses are transmitted to the heart via output amplifier 6 and connection 10.
  • Each issued pulse resets counter 2 via OR gate 8 and delay 9 so that the counter commences its count for the next "normal” pulse.
  • the delay provided by delay 9 sets the pulse width for each pulse issued by counter 2.
  • the circuit thus far described is acting as a conventional demand pacemaker, only issuing tissue stimulating pulses for output to the heart when a natural beat is missing.
  • each will not only reset counter 2 but hold flip-flop 7 reset. The latter holds in the "0" state ready to steer a Ox "slow” pulse to the output once the natural beats decrease in period to below the Qx rate.
  • the hysteresis function is illustrated by Figure 2 (c), (d) and (e).
  • the next artificial pulse is issued at the Qx "slow” rate.
  • the pacemaker reverts to issuing "normal” pulses until the next natural beat arises.
  • the next natural beat is one of a succession of three natural beats and no artificial pulse is issued.
  • one Qx "slow” pulse is issued before the pacemaker again reverts to its "normal” rate.
  • program store 13 would have the added capability of altering, inter alia, the "normal" pulse rate. This may be accomplished by expanding the outputs obtained from counter 2, and increasing the number of AND and OR gates 3, 4, and 5, and supplying the outputs of the OR gates to a rate decoder which selects, under control from program store 13, the "normal" rate to be generated.
  • Figure 3 An example of this is indicated in Figure 3 where the number of outputs from counter 2 has been expanded to 5 (Q 1 to Q 5 ).
  • Figure 3 is identical to Figure 1 except as indicated.
  • the lower numbered stage can be considered as providing the "normal” pulse rate and the adjacent higher numbered stage as providing the "slow" pulse rate (i.e. Q 1 normal, Q 2 slow; Q 2 normal, Q 3 slow ).
  • This provides a total of four normal/slow pulse rate combinations which can be individually selected by a rate decoder 16. The particular rate combination selected is determined by the logic levels on lines 17 held in store 13.

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  • 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 (5)

1. Bedarfsherzschrittmacher mit einer Raten-Hysteresefunktion, welche mittels getrennter Programmiermittel programmierbar gespeichert werden kann, so daß dieser Betriebszustand nach Wunsch einstellbar ist, mit:
a) einem Oszillator (1), welcher mit einer vorgegebenen Rate arbeitet,
b) einem Ausgangsverstärker (6) zum Erzeugen von künstlichen Stimulationsimpulsen,
c) einem Eingagsverstärker (11) zum Aufnehmen von auftretenden natürlichen Herzschlagsignalen,
d) Mitteln, welche einen Speicher (13) umfassen, der durch die äußeren Programmiermittel programmierbar ist, um den Schrittmacher gegebenenfalls in seinem Hysterese-Betriebszustand zu betreiben,

dadurch gekennzeichnet, daß der Schrittmacher enthält:
e) Zählmittel (2), welche von Oszillator (1) beeinflußt werden, um Ausgangsimpulse mit wenigstens zwei verschiedenen Zählraten (Qy, Ox) abzugeben,
f) Schaltmittel (3, 4), welche alternativ auf die Zählraten hin ansprechen, um den Ausgangsverstärker (6) zu aktivieren und
g) logische Mittel (7, 15), welche von dem Speicher (13) und dem Eingangsverstärker (11) angesteuert werden, um die Schaltmittel (3, 4) zu beeinflussen, wodurch, wenn der Speicher (13) angibt, daß der Raten-Hysteresezustand nicht programmiert ist, der Ausgangsverstärker (6) Zählimpulse mit einer ersten Zählrate erhält und, wenn der Programmspeicher (13) angibt, daß der Hysteresezustand programmiert ist, der Ausgangsverstärker (6) mindestens einen Impuls mit der zweiten Impulsrate erhält, nachdem durch die logischen Mittel wenigstens ein natürlicher Herzschlag aufgenommen wurde.
2. Bedarfsherzschrittmacher nach Anspruch 1, dadurch gekennzeichnet, daß die logischen Schaltmittel ein Flip-Flop (7) enthalten, mit ersten und zweiten logischen Zuständen, welche die Schaltmittel (3, 4) ansteuern, um den Ausgangsverstärker (11) zum Empfang der Zählimpulse mit der ersten bzw. zweiten Rate zu aktivieren.
3. Bedarfsherzschrittmacher nach Anspruch 2, dadurch gekennzeichnet, daß die Schaltmittel erste (3) bzw. zweite (4) Tormittel enthalten, welche Ausgangsimpulse mit ersten und zweiten Raten aufnehmen, wobei die Tormittel in komplementärer Weise durch die ersten und zweiten logischen Zustände des Flip-Flops (7) aktiviert werden.
4. Bedarfsherzschrittmacher nach Anspruch 3, dadurch gekennzeichnet, daß die logischen Schaltmittel umfassen: erste Mittel, welche Mittel (8, 9) enthalten, die auf künstliche Stimulationsimpulse oder natürlich auftretende Herzsignale ansprechen, um die Zählmittel (2) in einen Datenzustand zurückzusetzen und Mittel (CK bei 7), welche auf künstliche Stimulationsimpulse ansprechen, um das Flip-Flop (7) derart zu setzen, daß die ersten Tormittel (3) aktiviert werden sowie zweite Mittel (15), welche auf die Speichermittel (13) ansprechen, falls die Raten-Hysteresefunktion aktiviert ist und auf ein natürlich auftretendes Herzsignal, um das Flip-Flop (7) zurückzusetzen, so daß die zweiten Tormittel (4) aktiviert sind.
5. Bedarfsherzschrittmacher nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Zählmittel (2) derart ausgebildet sind, daß sie Ausgangsimpulse mit mehr als der ersten und zweiten Impulsrate abgeben Können, wobei die zusätzlichen Raten jeweils vorgegebenen Stimulationsimpulsraten entsprechen, und der Speicher (13) zusätzliche Mittel (17) umfaßt, um eine oder mehrere zusätzliche Raten auszuwählen, wobei die Schaltmittel weitere Mittel (3'-33, 41-44, 51-54, 16) umfassen, welche vom Speicher (13) und zusätzlichen logischen Mitteln angesteuert werden, um Impulse mit jeder der vorgegebenen lmpulsraten an den Ausgangsverstärker '(6) abzugeben.
EP78300241A 1977-08-19 1978-08-03 Bedarfschrittmacher mit programmierbarer Frequenz-Hysteresis Expired EP0000987B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB3491377 1977-08-19
GB3491377 1977-08-19
US917141 1978-06-19
US05/917,141 US4169480A (en) 1977-08-19 1978-06-19 Demand pacer with programmable rate hysteresis

Publications (2)

Publication Number Publication Date
EP0000987A1 EP0000987A1 (de) 1979-03-07
EP0000987B1 true EP0000987B1 (de) 1982-01-20

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EP78300241A Expired EP0000987B1 (de) 1977-08-19 1978-08-03 Bedarfschrittmacher mit programmierbarer Frequenz-Hysteresis

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EP (1) EP0000987B1 (de)
AU (1) AU3895478A (de)
CA (1) CA1098588A (de)
DE (1) DE2861544D1 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1118131B (it) * 1978-07-20 1986-02-24 Medtronic Inc Perfezionamento nei pacemaker cardiaci multi-modo adattabili impiantabili
US4263915A (en) * 1978-11-06 1981-04-28 Medtronic, Inc. Digital cardiac pacemaker with hysteresis
JPS612348Y2 (de) * 1980-10-09 1986-01-25
WO1982003783A1 (en) * 1981-05-04 1982-11-11 Nettelhorst Herwig Pacemaker

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833005A (en) * 1971-07-26 1974-09-03 Medtronic Inc Compared count digitally controlled pacemaker
US3999557A (en) * 1975-07-11 1976-12-28 Medtronic, Inc. Prophylactic pacemaker

Also Published As

Publication number Publication date
EP0000987A1 (de) 1979-03-07
AU3895478A (en) 1980-02-21
DE2861544D1 (en) 1982-03-04
CA1098588A (en) 1981-03-31

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