EP0000984A1 - Stimulateur programmable avec amplificateur a gain variable - Google Patents
Stimulateur programmable avec amplificateur a gain variable Download PDFInfo
- Publication number
- EP0000984A1 EP0000984A1 EP78300237A EP78300237A EP0000984A1 EP 0000984 A1 EP0000984 A1 EP 0000984A1 EP 78300237 A EP78300237 A EP 78300237A EP 78300237 A EP78300237 A EP 78300237A EP 0000984 A1 EP0000984 A1 EP 0000984A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pacer
- amplifier
- signals
- output
- input amplifier
- 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.)
- Granted
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Classifications
-
- 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 implantable body function control apparatus and particularly, but not exclusively, to body tissue stimulating devices such as 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 heart 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.
- an implantable, body tissue stimulating apparatus comprising means for providing electrical signals for artificially stimulating body tissue in relation to sensed signals, said providing means including an input amplifier for receiving input signals from the body and for providing output signals for controlling the operation of the apparatus, means, for controlling the magnitude of the output signals provided by the input amplifier, a program store for holding a program which controls said magnitude controlling means, and means for changing the program stored by the program store.
- the magnitude control means can take several forms, but preferably includes a potential dividing network which by means of switching resistors into and out of the network, can be employed to control the signal levels at the input amplifier, This can be accomplished either on the input side of the amplifier (the input signals being supplied to the network before passing to the amplifier), by including the network in an amplifier feed-back loop (enabling the amplifier gain to be varied), or on the output side of the amplifier. Of these three alternatives, the first is preferred.
- 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 minutel.
- 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' (R 1 ).
- 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 V DD .
- 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).
- 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 this 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)
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 true EP0000984A1 (fr) | 1979-03-07 |
EP0000984B1 EP0000984B1 (fr) | 1983-05-11 |
Family
ID=26262494
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) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2440199A1 (fr) * | 1978-11-06 | 1980-05-30 | Medtronic Inc | Stimulateur cardiaque a la demande |
EP0491907A1 (fr) * | 1990-07-06 | 1992-07-01 | Medtronic Inc | Procede et appareil permettant d'acceder a une memoire remanente. |
US11944526B2 (en) | 2013-09-19 | 2024-04-02 | The Procter & Gamble Company | Absorbent cores having material free areas |
Citations (2)
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 |
LU76880A1 (fr) * | 1976-03-03 | 1977-07-12 |
-
1978
- 1978-08-03 EP EP19780300237 patent/EP0000984B1/fr not_active Expired
- 1978-08-03 DE DE7878300237T patent/DE2862246D1/de not_active Expired
- 1978-08-16 AU AU38957/78A patent/AU3895778A/en active Pending
- 1978-08-17 CA CA309,563A patent/CA1098591A/fr not_active Expired
Patent Citations (2)
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 |
LU76880A1 (fr) * | 1976-03-03 | 1977-07-12 |
Non-Patent Citations (1)
Title |
---|
ELECTRONICS, vol. 48, nr. 14, July 10, 1975, New York. C.J. HARTLEY: "Digital word sets gain of amplifier", pages 94,95 * |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2440199A1 (fr) * | 1978-11-06 | 1980-05-30 | Medtronic Inc | Stimulateur cardiaque a la demande |
EP0011932A2 (fr) * | 1978-11-06 | 1980-06-11 | Medtronic, Inc. | Stimulateur cardiaque |
EP0011932A3 (fr) * | 1978-11-06 | 1981-01-07 | Medtronic, Inc. | Stimulateur cardiaque |
EP0491907A1 (fr) * | 1990-07-06 | 1992-07-01 | Medtronic Inc | Procede et appareil permettant d'acceder a une memoire remanente. |
EP0491907A4 (en) * | 1990-07-06 | 1993-02-24 | Medtronic, Inc. | Method and apparatus for accessing a nonvolatile memory |
US11944526B2 (en) | 2013-09-19 | 2024-04-02 | The Procter & Gamble Company | Absorbent cores having material free areas |
Also Published As
Publication number | Publication date |
---|---|
EP0000984B1 (fr) | 1983-05-11 |
AU3895778A (en) | 1980-02-21 |
CA1098591A (fr) | 1981-03-31 |
DE2862246D1 (en) | 1983-06-16 |
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