US3631860A - Variable rate pacemaker, counter-controlled, variable rate pacer - Google Patents

Variable rate pacemaker, counter-controlled, variable rate pacer Download PDF

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US3631860A
US3631860A US869463A US3631860DA US3631860A US 3631860 A US3631860 A US 3631860A US 869463 A US869463 A US 869463A US 3631860D A US3631860D A US 3631860DA US 3631860 A US3631860 A US 3631860A
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pacer
transistor
reed switch
accordance
pulse
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US869463A
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Michael Lopin
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American Optical Corp
Warner Lambert Co LLC
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American Optical Corp
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Assigned to COOK PACEMAKER CORPORATION reassignment COOK PACEMAKER CORPORATION LICENSE (SEE DOCUMENT FOR DETAILS). EFFECTIVE 03/27/81 Assignors: ATLANTIC RICHFIELD COMPANY
Assigned to WARNER LAMBERT COMPANY A CORP. OF DE reassignment WARNER LAMBERT COMPANY A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: AMERICAN OPTICAL CORPORATION A CORP. OF DE
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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
    • A61N1/37211Means for communicating with stimulators
    • A61N1/37217Means for communicating with stimulators characterised by the communication link, e.g. acoustic or tactile
    • 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
    • A61N1/362Heart stimulators
    • A61N1/365Heart stimulators controlled by a physiological parameter, e.g. heart potential

Definitions

  • ABSTRACT A variable rate pacer having two flip-flops for defining four possible states. Each state determines the magnitude of a charging current which in turn determines the rate of the pacer.
  • the flip-flops arranged in a counter configuration, are cycled by a monostable magnetic reed switch which is pulsed by placing an external magnetic field in the vicinity of the patients chest.
  • the magnetic reed switch is used only for cycling the counter to establish the proper rate of operation; the reed switch is not required for maintaining the charging current once it is established. Reliability of operation is improved because, unlike the prior art, mechanical switches are not required for maintaining the selected charging current level.
  • SHEET 2 [1F 2 ⁇ Nm WNW P PATENTED JAN 41972 VARIABLE RATE PACEMAKER, COUNTER- CONTROLLED, VARIABLE RATE PACER This invention relates to pacers, and more particularly to a variable rate pacer whose rate of operation can be adjusted after implantation in a patient.
  • a demand pacer is primed to generate an impulse at a predetermined time after the last natural heartbeat. If another heartbeat occurs during the timing interval of the pacer, an impulse is not generated and the timing period starts all over again. On the other hand, if a natural heartbeat does not take place by the end of the timing period a stimulating impulse is generated.
  • the pacer circuitry must determine if a natural heartbeat has occurred. The largest magnitude electrical signal generated by the heart activity is the ORS-complex corresponding to a ventricular contraction.
  • an electrode is generally coupled to a ventricle. Since in most cases ventricular stimulation is required, the same electrode can be used for both stimulating the ventricles and detecting a natural heartbeat, as disclosed in the aforesaid Berkovits patent.
  • a demand pacer of this type In the presence of noise, erroneous operation of a demand pacer of this type can take place.
  • the noise may result in the generation of an electrical signal on the ventricular electrode, and the pacer circuitry may treat this noise as indicative of a natural heartbeat and inhibit the generation of a stimulating impulse even if one is required.
  • an im proved demand pacer is disclosed in the copending application of Barouh V. Berkovits, Ser. No. 727,129 filed on Apr. 11, 1968, which has matured into US. Pat. No. 3,528,428, an im proved demand pacer is disclosed.
  • the pacer timing period In this improved demand pacer, in the presence of the noise the pacer timing period is not interrupted. Continuous stimulating impulses are generated, even if they are not required. It is better to provide an impulse even if it is not required than it is not to provide an impulse if it is required.
  • the pacer In the pacer disclosed in the above-identified copending Berkovits application, there is a single switch and two potentiometers which can be manually adjusted to change the pacer operation. Depending on the setting of the switch, the pacer operates in either a continuous mode or a demand mode. The first potentiometer controls the width of each generated pulse. The second potentiometer controls the interpulse interval. If the switch and the potentiometers cannot be adjusted after they are implanted in the patient, it is apparent that the pacer can operate in only one of the two possible modes, and with only a single pulse width and only a single interpulse interval.
  • Magnetic reed switches can be used for this purpose.
  • An example of the use of a magnetic reed switch for controlling the rate of a demand pacer is disclosed in the copending application of Barouh V. Berkovits, Ser. No. 862,695 filed on Oct. 1, 1969.
  • the magnetic reed switches which have been used in the prior art to control the rate of a pacer have been of the bistable type.
  • the magnetic reed is set in one or another of two states depending on the polarity of the magnetic field brought into the vicinity of the patients chest. Each state of the reed controls a different rate.
  • a resistor in the pacer-timing circuit is shorted out when the reed switch is closed, and it is placed in the circuit to decrease the rate when the reed switch is open.
  • bistable magnetic reed switches, or other types of mechanical switches, in this manner is one of reliability. It
  • the switch described above consists of amonostable magnetic reed.
  • a magnetic pole of either polarity When a magnetic pole of either polarity is placed adjacent to the patient's chest, the reed is closed and the pacer operates in the continuous mode: When the magnet is removed, the reed opens and the pacer functions in the demand mode.
  • One of the most important reasons for switching to the continuous mode is to allow the physician to check the pacer operation. If the patient's heart is beating normally, no pulses are generated by the pacer. Even if the pahas been found that if a mechanical contact is required to maintain a selected rate, shock and vibration can cause inadvertant changes. This is true not only of bistable magnetic reed switches, but also of many other mechanical contact switches used for the same purpose. It is apparent that it is highly undesirable for the pacer rate to accidentally change after setting by the physician.
  • the interpulse interval is determined by an RC-timing circuit.
  • a capacitor charges from a voltage source through a resistor, the charging rate being dependent upon the magnitude of the resistor.
  • the capacitor is charged directly from a constant current source, the magnitude of the constant current delivered by this source is dependent upon the state of a twobit counter.
  • the counter can be set in any one of four states, and thus four different pacer rates are possible.
  • the counter is constructed of bistable electronic circuits which do not rely upon mechanical contacts for maintaining them in particular states once they are set.
  • a monostable magnetic reed switch Coupled to the counter is a monostable magnetic reed switch.
  • the switch is normally open. When a magnetic field is brought into the vicinity of the patients chest, the switch closes. The closing of the switch pulses the counter to advance its state. This in turn results in a change in pacer rate. Once the counter is set in a particular state, this state is maintained independent of the condition of the reed switch. When the magnetic field is removed, the reed switch opens but the counter state and current level remain the same. Because the pacer rate is not maintained by the reed switch (the reed switch remains open), the pacer rate is not affected by mechanical shock or vibration. Of course, it is possible for other types of devices to be used for pulsing the electronic circuits to change their states as required. However, it has been found that a moiiostable magnetic reed switch is particularly advantageous for use as the rate-changing control mechanism.
  • FIG. 1 is the same as FIG. 1 in the copending application of Barouh V. Berkovits, Ser. No. 727,129 which has matured into U.S. Pat. No. 3,528,428, and depicts a demand pacer;
  • FIG. 2 depicts a typical electrocardiogram
  • FIG. 3 depicts the illustrative embodiment of the present invention.
  • electrodes El and E2 are implanted in the patients heart, electrode E2 being the neutral electrode and electrode E1 being positioned to stimulate the ventricles.
  • switch S When switch S is open, current flows between electrodes E1 and E2 to stimulate the ventricles only when an electrical stimulus is required.
  • Capacitor 65 serves to provide a source of current when an impulse is required. At that time, transistor T9 conducts and the capacitor discharges through the electrodes. Capacitor 57 charges through potentiometers 35 and 37 until the voltage across it causes transistors T7 and T8 to conduct. At that time, capacitor 57 discharges through potentiometer 37 and transistors T7 and T8, transistor T9 conducts, and an impulse is delivered to the patients heart from capacitor 65. The setting of potentiometer 37 controls the time taken for capacitor 57 to discharge, that is, the width of each impulse.
  • potentiometer 35 (along with the setting of potentiometer 37) controls the time required for capacitor 57 to charge to that level which causes conduction in transistors T7 and T8, that is, the interpulse interval. Ordinarily, in the absence of conduction of transistor T6, capacitor 57 would continuously charge and discharge, and impulses would be supplied to the patients heart at fixed intervals determined by the setting of the potentiometers.
  • Electrode E1 is coupled over conductor 11 to the base of transistor T1 through capacitor 17.
  • a representative ECG- trace is shown in FIG. 1, and transistors T1 and T2 amplify the R-wave signal on electrode El resulting from a ventricular contraction. (Excessive signals are shorted through Zener diode 67 to prevent damage to transistor T1.)
  • a positive pulse is delivered to the base of transistor T6.
  • Transistor T6 turns on and capacitor 57 discharges through it.
  • the capacitor was previously charging to the level which would have resulted in the generation of an impulse, it is discharged and a new timing interval begins. This arrangement insures that an impulse is not generated if a natural heartbeat has occurred.
  • the timing interval is such that impulses are generated with an interpulse interval slightly in excess of the desired natural interbeat interval. Only if a natural heartbeat is missing is a stimulating impulse generated.
  • the pacer With switch S open, as shown, the pacer operates in the demand mode as just described. However, with switch S closed, the base of transistor T6 is held at the potential of conductor 9. In such a case, pulses transmitted through capacitor 53 do not turn on the transistor. Capacitor 57 is not discharged through transistor T6 and each time the capacitor voltage rises to the point where transistors T7 and T8 conduct, a stimulating pulse is generated. The pacer thus operates in the continuous mode.
  • FIG. 3 The illustrative embodiment of my invention is shown in FIG. 3.
  • the circuit is identical to that of FIG. 1 except for the elements shown within heavy outlines-switch S and box 35'.
  • the left half of the circuit of FIG. 1 is not repeated on FIG. 3, it being understood that to the left of transistors T3 and T5 the two circuits are identical.
  • Switch S is shown as a monostable magnetic reed switch.
  • the switch includes two reeds encased in a glass enclosure. Such a monostable magnetic reed switch has been used in pacers for several years. When a magnet is brought into the vicinity of the monostable magnetic reed switch, the two reeds engage if the magnet flux is parallel to them.
  • the base of transistor T6 is shorted through the reed switch to conductor 9 and the pacer operates in the continuous mode. As soon as the magnet is removed, the switch opens and the pacer reverts to the demand mode of operation.
  • potentiometer 35 is connected at one end to the junction of resistor 33 and battery 7, and at the other end to the junction of potentiometer 37 and the emitter of transistor T7.
  • Box 35' on FIG. 3 has three input conductors, two of which are connected between the same two junctions. The third input to the box couples the base of transistor T14 to the junction of batteries 5 and 7.
  • potentiometer 35 serves to control the current (an exponential waveform) which flows from battery 7 to capacitor 57.
  • box 35' serves as a constant current source which delivers current through potentiometer 37 to capacitor 57. (It is also possible to connect the collector of transistor T14 directly to capacitor 57 so that potentiometer 37 is not in the charging current path.)
  • the constant current is delivered through potentiometer 37 to capacitor 57 from the collector of transistor T14.
  • the current flows through the potentiometer and the capacitor, and through resistors 61 and 63 to ground conductor 9.
  • the charging current is small so that the voltage developed across resistor 63 is small enough to prevent conduction of transistor T9. It is only when capacitor 57 discharges through transistors T7 and T8 that the current through resistor 63 is large enough to turn on transistor T9.
  • the current source There are two requirements for the current source represented by box 35'. The first is that the current source function over the entire voltage range of capacitor 57.
  • the maximum voltage across the capacitor is that which fires transistors T7 and T8.
  • Capacitor 57 is connected at one end through resistors 61 and 63 to ground conductor 9. The voltage across resistors 61 and 63 during charging of the capacitor is negligible so one end of the capacitor may be considered to be grounded during charging.
  • the base of transistor T7 is held at a potential V detennined by batteries 3 and 5. Transistor T7 conducts when its base-emitter voltage is 0.4 volts. Consequently, the maximum voltage across capacitor 57 is equal to V 0.4 volts.
  • the constant current source must function over the voltage range from 0 to V 0.4 volts.
  • the second requirement of the constant current source is that the voltage at the emitter of transistor T14 not change when Transistors T7 and T8 conduct. If the voltage changes, it is possible for the bistable circuits within box 35 to be switched. To prevent changes in the charging current level, the voltage at the emitter of transistor T14 should not change even when capacitor 57 discharges through transistors T7 and T8.
  • the base potential of transistor T14 is held constant by batteries 3 and 5 and is the same as the base potential of transistor T7, V.
  • Transistor T14 starts to conduct when its emitter voltage is approximately 0.4 volts greater than its base voltage. Although an emitter-base forward bias of 0.4 volts is sufficient to cause the transistor to start conducting, the emitter-base voltage drop is 0.5 volts when the transistor operates linearly and is conducting the charging current. Since the base of transistor T14 is held at a constant potential of V volts, the emitter of transistor T14 is held at a constant potential of V volts, the emitter of transistor T14 is at a potential 0.5 volts greater than the base potential essentially independent of the magnitude of the emitter current.
  • the collector current equals the emitter current multiplied by the parameter a of the transistor (typically, a value of 0.99).
  • Transistor T14 functions as a current source with the emitter potential being greater than the base potential by 0.5 volts only if the emitter-collector voltage drop is greater than approximately 0.1 volts, that is, only if the collector voltage does not exceed V 0.4 volts.
  • transistor T14 functions as a constant current source independent of the emitter-collector voltage drop, it is necessary that there be a drop.
  • transistors T7 and T8 turn on to discharge capacitor 57 when the emitter voltage of transistor T7 rises to'V 0.4 volts, it is apparent that the collector voltage of transistor T14 cannot rise higher than that value which would prevent the transistor from operating as a constant current source.
  • transistor T14 functions as a constant current source over the entire voltage range of capacitor 57.
  • the emitter impedance of transistor T14 is relatively small compared with resistors 70-73 which, as will be described below, determine the emitter current of transistor T14.
  • the emitter of transistor T14 thus appears as a voltage source to the counter circuitry in box 35', that is, the transistor conducts any of the four possible currents without any changes in its emitter potential. Transistor T14 thus prevents spurious switching of the bistable circuits within box 35' as a result of the operation of the timing circuit.
  • Transistor T14 functions as a current summer; the emitter current is the sum of the currents flowing into common bus 97 from the conducting ones of transistors T10-T13, all of the emitter terminals of these transistors being connected to the emitter of transistor T14.
  • Transistors T10 and T1 1 form a first flip-flop and transistors T12 and T13 form a second flip-flop.
  • the four collector resistors 70-73 are connected to respective transistors.
  • the collector of transistor T10 is coupled to the base of transistor T11 through resistor 78, and the collector of transistor T1 1 is coupled to the base of transistor T10 through resistor 79.
  • Resistors 80 and 81 serve to cross-couple transistors T12 and T13 in a similar manner.
  • Capacitors 74-77 are speed-up capacitors which, as in known in the art, increase the speed and reliability of the flip-flop switching.
  • transistor T10 is conducting and transistor T11 is off.
  • the base-emitter drop across transistor T11 is similarly 0.1 volts. Since a 0.4-volt drop is necessary to cause the transistor to conduct, the transistor remains off. Current flows from battery 7 through resistors 71 and 79 to the base of transistor T10 to maintain the transistor conducting.
  • the cathode of diode 86 With transistor T10 conducting and its collector at 0.1 volts relative to the potential of bus 97, the cathode of diode 86 is similarly held at this potential.
  • the base-emitter drop of transistor T10 is 0.5 volts, and consequently the cathode of diode 84 is held at a potential of 0.5 volts relative to the potential of bus 97.
  • Application of a negative pulse to the anode of either diode has no effect since the diode does not conduct when the anode-cathode drop is negative. In order for either diode to conduct, its anode must be 0.5 volts higher in potential than its cathode.
  • capacitor 83 When magnetic reed switch S closes, the positive potential of source 7 is applied to capacitor 83.
  • the capacitor and resistor from a differentiating circuit and thus a positive spike is applied to the anodes of diodes 84 and 86.
  • the component values are such that the positive pulse has an amplitude greater than 0.6 volts but less than 1 volt so that the flip-flop switches state as described above.
  • a negative pulse is applied through capacitor 83 to the anodes of the two diodes. The negative pulse, however, has no effect since it further reverse biases both diodes. Following the closing and opening of the contacts, capacitor 83 discharges through resistors 85 and 82.
  • the cathode of diode 84 is at 0.1 volts and the cathode of diode 86 is at 0.5 volts.
  • the next positive pulse produced by the closing of the reed contacts is steered through diode 84 to cause transistor T10 to turn on and transistor T11 to turn off.
  • Successive positive pulses produced by the closing of switch S switch the state of the Elements 88-92 are comparable to elements 82-86 and serve to switch the state of the flip-flop comprising transistors T12 and T13 when a positive potential is applied to the junction of resistor 88 and capacitor 89.
  • the positive potential is derived when transistor T11 turns off and its collector rises in potential. At this time, a positive step is transmitted through capacitor 87.
  • the capacitor is provided to isolate the junction of resistor 71 and the collector of transistor T11 from the second flip-flop in order that the second flip-flop not affect the bias voltages of the first flip-flop.
  • the second flip-flop changes state only when transistor T11 switches from a conducting to a nonconducting state. When the transistor switches from the nonconducting state to the conducting state, it is a negative voltage step which is transmitted through capacitor 87, and the resulting negative pulse transmitted through capacitor 89 simply further reverse biases diodes 90 and 92 and has no effect on the second flip-flop.
  • the two flip-flops function as a four-state counter.
  • the emitter potential of transistor T14 is V 0.5 volts, where the base potential of transistor T14 is V volts.
  • the inclusion of battery 7 in the circuit increases the potential at the upper ends of each of resistors 70-73 to V volts, where V is greater than V.
  • the potential drop across a conducting one of transistors T-T13 in series with its collector resistor is V (V,,, 0.5 volts.
  • V potential drop across a conducting one of transistors T-T13 in series with its collector resistor
  • resistor 70 has a magnitude of 10 ohms
  • resistors 71 and 72 both have a magnitude of 2(10) ohms
  • resistor 73 has a magnitude of 4(10) ohms.
  • resistors 78-81 have been omitted.
  • transistor T10 conducts a current of 2 microamperes flows through resistor 70 and the transistor to bus 97 as described. But current also flows through resistors 71 and 79, and the base-emitter junction of transistor T10 to the common bus.
  • resistor 79, and the other three cross-coupling resistors are very large in magnitude compared to the four collector resistors, and do not affect appreciably the current levels described above. In any event, what is of importance is the four current levels themselves, not the manner in which they are derived.
  • the values of the collector and crosscoupling resistors can be selected such that the four possible emitter currents of transistor T14 are the desired values.
  • the prior art monostable reed switch S can still be used as in the past.
  • the physician can verify that the pacer is still operational if the electrocardiogram of the patient shows that the pacer has switched to the continuous mode of operation when a magnet has been brought into the vicinity of the patients chest.
  • the additional switch S can be arranged so that the same magnet controls a change in the pacer rate. If the same magnetic field closes both reed switches, the pacer will function in the continuous mode at the same time that its rate is changed; when the magnetic field is removed the pacer switches to the demand mode and continues to operate at the new rate. However, it is preferable to operate the two reed switches independently. As shown in FIG.
  • the orientations of the two monostable magnetic reed switches are perpendicular to each other.
  • a magnetic field in one direction will cause one of the switches to close and a magnetic field in a perpendicular direction will cause the other reed to close.
  • reed switch S for a continuous pacer there would be no need for reed switch S in the first place and the problem of independent reed operation would not even exist.
  • a rate adjustment may be made simply by holding a magnet against the patient's chest.
  • the pacer may include an RF detector, with the counter being cycled each time an RF transmitter is operated in the vicinity of the patient's chest.
  • other multistate electronic circuits could be utilized, e.g., those incorporating tunnel diodes, 4-layer diodes, etc.
  • the counter can be constructed to have any desired number of states. A single flip-flop could be used for only two states, i.e., if only two current levels are required. if more than four states are required, more that two flip-flops could be utilized.
  • a pacer comprising terminal means for connection to a patient's heart and pulse-generating means for applying periodic pulses to said terminal means, said pulse-generating means including multistate electronic circuit means comprising an electronic counter for representing at least two states, normally inoperative pulsing means responsive to the detection of an external signal for changing the state of said multistate electronic circuit means, and means responsive to the state of said multistate electronic circuit means for maintaining a respective rate of operation of said pulse-generating means when said pulsing means is inoperative.
  • a pacer in accordance with claim 1 wherein said respective rate-maintaining means comprises a plurality of individual current-determining sources connected in parallel to and for feeding said constant current source, and means for controlling the operation of respective groups of said individual current-determining sources responsive to respective states being represented by said multistate electronic circuit means.
  • said constant current source includes means for summing the currents from said individual current-determining sources and for isolating said timing circuit from said multistate electronic circuit means to prevent the spurious switching thereof.
  • a pacer in accordance with claim 5 further including means for detecting the natural beating of said patients heart and in response thereto for inhibiting the generation of the next pulse which would otherwise be generated by said pulsegenerating means, and means including an additional monostable magnetic reed switch for selectively preventing the inhibiting of the operation of said pulse-generating means, said monostable magnetic reed switch and said additional monostable magnetic reed switch being oriented in said pacer such that each of said switches can be closed independent of the other responsive to the application of a magnetic field having a respective orientation.
  • said pulsing means includes means comprising a monostable magnetic reed switch for advancing the state of said counter responsive to the closing of said switch.
  • said pulsing means includes means comprising a monostable magnetic reed switch for advancing the state of said counter responsive to the closing of said switch.

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US869463A 1969-10-27 1969-10-27 Variable rate pacemaker, counter-controlled, variable rate pacer Expired - Lifetime US3631860A (en)

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Cited By (33)

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US3805796A (en) * 1971-05-10 1974-04-23 Cordis Corp Implantable cardiac pacer having adjustable operating parameters
US3810457A (en) * 1971-11-24 1974-05-14 Bosch Elektronik Gmbh Diagnostic apparatus for automatically generating an intensity-time diagram showing points of minimum involuntary muscle movement
US3833005A (en) * 1971-07-26 1974-09-03 Medtronic Inc Compared count digitally controlled pacemaker
US3865119A (en) * 1972-04-11 1975-02-11 Siemens Ag Heartbeat actuator with controlled pulse amplitude
US3905016A (en) * 1973-04-11 1975-09-09 Carl J Peterson Reverse signal alarm system
US3945387A (en) * 1974-09-09 1976-03-23 General Electric Company Implantable cardiac pacer with characteristic controllable circuit and control device therefor
FR2316919A1 (fr) * 1975-07-11 1977-02-04 Medtronic Inc Stimulateur prophylactique
US4037598A (en) * 1974-08-12 1977-07-26 Ivac Corporation Method and apparatus for fluid flow control
DE2944637A1 (de) * 1978-11-06 1980-05-14 Medtronic Inc Programmierbares medizinisches geraet
DE2944636A1 (de) * 1978-11-06 1980-05-14 Medtronic Inc Impulsgenerator fuer medizinische geraete
US4237895A (en) * 1979-04-20 1980-12-09 Medcor, Inc. Control signal transmitter and monitor for implanted pacer
WO1981001659A1 (en) * 1979-12-13 1981-06-25 American Hospital Supply Corp Programmable digital cardiac pacer
US4285345A (en) * 1979-07-02 1981-08-25 Vitatron Medical B.V. Monolithic pacemaker utilizing I2 L circuitry
US4416282A (en) * 1981-03-02 1983-11-22 Cordis Corporation Cardiac pacer with improved, output circuitry
US4556063A (en) * 1980-10-07 1985-12-03 Medtronic, Inc. Telemetry system for a medical device
US4958632A (en) * 1978-07-20 1990-09-25 Medtronic, Inc. Adaptable, digital computer controlled cardiac pacemaker
US5292342A (en) * 1992-05-01 1994-03-08 Medtronic, Inc. Low cost implantable medical device
US5324315A (en) * 1993-08-12 1994-06-28 Medtronic, Inc. Closed-loop downlink telemetry and method for implantable medical device
US5370668A (en) * 1993-06-22 1994-12-06 Medtronic, Inc. Fault-tolerant elective replacement indication for implantable medical device
US5387228A (en) * 1993-06-22 1995-02-07 Medtronic, Inc. Cardiac pacemaker with programmable output pulse amplitude and method
EP0657186A2 (en) 1993-12-09 1995-06-14 Medtronic, Inc. Cardiac pacemaker with triggered magnet modes
US5683432A (en) * 1996-01-11 1997-11-04 Medtronic, Inc. Adaptive, performance-optimizing communication system for communicating with an implanted medical device
US5697958A (en) * 1995-06-07 1997-12-16 Intermedics, Inc. Electromagnetic noise detector for implantable medical devices
US5722998A (en) * 1995-06-07 1998-03-03 Intermedics, Inc. Apparatus and method for the control of an implantable medical device
WO2000030529A1 (en) 1998-11-24 2000-06-02 Medtronic, Inc. World wide patient location and data telemetry system for implantable medical devices
US6198968B1 (en) 1998-01-23 2001-03-06 Intermedics Inc. Implantable cardiac stimulator with safe noise mode
US6249703B1 (en) 1994-07-08 2001-06-19 Medtronic, Inc. Handheld patient programmer for implantable human tissue stimulator
US20020045920A1 (en) * 2000-08-26 2002-04-18 Medtronic, Inc. Implanted medical device telemetry using integrated thin film bulk acoustic resonator filtering
US6453201B1 (en) 1999-10-20 2002-09-17 Cardiac Pacemakers, Inc. Implantable medical device with voice responding and recording capacity
US6535766B1 (en) 2000-08-26 2003-03-18 Medtronic, Inc. Implanted medical device telemetry using integrated microelectromechanical filtering
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US20050137490A1 (en) * 2001-04-11 2005-06-23 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US20060267551A1 (en) * 2005-05-31 2006-11-30 Sehat Sutardja Medical device

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DE3613283A1 (de) * 1986-04-19 1987-10-22 Osypka Peter Herzschrittmacher mit einem steuerteil zur erhoehung der herz-ruhefrequenz

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US3805796A (en) * 1971-05-10 1974-04-23 Cordis Corp Implantable cardiac pacer having adjustable operating parameters
US3833005A (en) * 1971-07-26 1974-09-03 Medtronic Inc Compared count digitally controlled pacemaker
US3810457A (en) * 1971-11-24 1974-05-14 Bosch Elektronik Gmbh Diagnostic apparatus for automatically generating an intensity-time diagram showing points of minimum involuntary muscle movement
US3865119A (en) * 1972-04-11 1975-02-11 Siemens Ag Heartbeat actuator with controlled pulse amplitude
US3905016A (en) * 1973-04-11 1975-09-09 Carl J Peterson Reverse signal alarm system
US4037598A (en) * 1974-08-12 1977-07-26 Ivac Corporation Method and apparatus for fluid flow control
US3945387A (en) * 1974-09-09 1976-03-23 General Electric Company Implantable cardiac pacer with characteristic controllable circuit and control device therefor
FR2316919A1 (fr) * 1975-07-11 1977-02-04 Medtronic Inc Stimulateur prophylactique
US5318593A (en) * 1978-07-20 1994-06-07 Medtronic, Inc. Multi-mode adaptable implantable pacemaker
US4958632A (en) * 1978-07-20 1990-09-25 Medtronic, Inc. Adaptable, digital computer controlled cardiac pacemaker
DE2944637A1 (de) * 1978-11-06 1980-05-14 Medtronic Inc Programmierbares medizinisches geraet
DE2944636A1 (de) * 1978-11-06 1980-05-14 Medtronic Inc Impulsgenerator fuer medizinische geraete
US4237895A (en) * 1979-04-20 1980-12-09 Medcor, Inc. Control signal transmitter and monitor for implanted pacer
US4285345A (en) * 1979-07-02 1981-08-25 Vitatron Medical B.V. Monolithic pacemaker utilizing I2 L circuitry
EP0025093A3 (en) * 1979-07-02 1982-05-26 Vitatron Medical B.V. Monolithic pacemaker utilizing i2l circuitry and amplifier
US4388927A (en) * 1979-12-13 1983-06-21 American Hospital Supply Corporation Programmable digital cardiac pacer
WO1981001659A1 (en) * 1979-12-13 1981-06-25 American Hospital Supply Corp Programmable digital cardiac pacer
US4556063A (en) * 1980-10-07 1985-12-03 Medtronic, Inc. Telemetry system for a medical device
US4416282A (en) * 1981-03-02 1983-11-22 Cordis Corporation Cardiac pacer with improved, output circuitry
US5292342A (en) * 1992-05-01 1994-03-08 Medtronic, Inc. Low cost implantable medical device
US5402070A (en) * 1993-06-22 1995-03-28 Medtronic, Inc. Fault-tolerant elective replacement indication for implantable medical device
US5370668A (en) * 1993-06-22 1994-12-06 Medtronic, Inc. Fault-tolerant elective replacement indication for implantable medical device
US5387228A (en) * 1993-06-22 1995-02-07 Medtronic, Inc. Cardiac pacemaker with programmable output pulse amplitude and method
US5324315A (en) * 1993-08-12 1994-06-28 Medtronic, Inc. Closed-loop downlink telemetry and method for implantable medical device
EP0657186A2 (en) 1993-12-09 1995-06-14 Medtronic, Inc. Cardiac pacemaker with triggered magnet modes
US5529578A (en) * 1993-12-09 1996-06-25 Medtronic, Inc. Cardiac pacemaker with triggered magnet modes
US6249703B1 (en) 1994-07-08 2001-06-19 Medtronic, Inc. Handheld patient programmer for implantable human tissue stimulator
US5697958A (en) * 1995-06-07 1997-12-16 Intermedics, Inc. Electromagnetic noise detector for implantable medical devices
US5722998A (en) * 1995-06-07 1998-03-03 Intermedics, Inc. Apparatus and method for the control of an implantable medical device
EP1334747A2 (en) 1995-06-23 2003-08-13 Medtronic, Inc. Worldwide patient location and data telemetry system for implantable medical devices
USRE42934E1 (en) 1995-06-23 2011-11-15 Medtronic, Inc. World wide patient location and data telemetry system for implantable medical devices
US6083248A (en) * 1995-06-23 2000-07-04 Medtronic, Inc. World wide patient location and data telemetry system for implantable medical devices
US5843139A (en) * 1996-01-11 1998-12-01 Medtronic, Inc. Adaptive, performance-optimizing communication system for communicating with an implanted medical device
US5683432A (en) * 1996-01-11 1997-11-04 Medtronic, Inc. Adaptive, performance-optimizing communication system for communicating with an implanted medical device
US6198968B1 (en) 1998-01-23 2001-03-06 Intermedics Inc. Implantable cardiac stimulator with safe noise mode
WO2000030529A1 (en) 1998-11-24 2000-06-02 Medtronic, Inc. World wide patient location and data telemetry system for implantable medical devices
US6453201B1 (en) 1999-10-20 2002-09-17 Cardiac Pacemakers, Inc. Implantable medical device with voice responding and recording capacity
US6865424B2 (en) 1999-10-20 2005-03-08 Cardiac Pacemakers, Inc. Implantable medical device with voice responding and recording capacity
US20090228058A1 (en) * 1999-10-20 2009-09-10 Daum Douglas R Implantable medical device with voice responding and recording capacity
US7962210B2 (en) 1999-10-20 2011-06-14 Cardiac Pacemakers, Inc. Implantable medical device with voice responding and recording capacity
US7551962B2 (en) 1999-10-20 2009-06-23 Cardiac Pacemakers, Inc. Implantable medical device with voice responding and recording capacity
US6535766B1 (en) 2000-08-26 2003-03-18 Medtronic, Inc. Implanted medical device telemetry using integrated microelectromechanical filtering
US20020045920A1 (en) * 2000-08-26 2002-04-18 Medtronic, Inc. Implanted medical device telemetry using integrated thin film bulk acoustic resonator filtering
US6868288B2 (en) 2000-08-26 2005-03-15 Medtronic, Inc. Implanted medical device telemetry using integrated thin film bulk acoustic resonator filtering
US20050137490A1 (en) * 2001-04-11 2005-06-23 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US7883470B2 (en) 2001-04-11 2011-02-08 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US20110105933A1 (en) * 2001-04-11 2011-05-05 Avram Scheiner Apparatus and method for outputting heart sounds
US7052466B2 (en) 2001-04-11 2006-05-30 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US8167811B2 (en) 2001-04-11 2012-05-01 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US8478391B2 (en) 2001-04-11 2013-07-02 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US8663123B2 (en) 2001-04-11 2014-03-04 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US8905942B2 (en) 2001-04-11 2014-12-09 Cardiac Pacemakers, Inc. Apparatus and method for outputting heart sounds
US7725182B2 (en) * 2005-05-31 2010-05-25 Marvell World Trade Ltd. Power distribution system for a medical device
US20060267551A1 (en) * 2005-05-31 2006-11-30 Sehat Sutardja Medical device

Also Published As

Publication number Publication date
GB1331967A (en) 1973-09-26
DE2048612C2 (de) 1982-04-22
DE2048612A1 (de) 1971-04-29
JPS5120832B1 (enExample) 1976-06-28

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