US3433228A - Multimode cardiac pacer - Google Patents

Multimode cardiac pacer Download PDF

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Publication number
US3433228A
US3433228A US548239A US3433228DA US3433228A US 3433228 A US3433228 A US 3433228A US 548239 A US548239 A US 548239A US 3433228D A US3433228D A US 3433228DA US 3433228 A US3433228 A US 3433228A
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Prior art keywords
heart
multivibrator
diode
pulse
time
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US548239A
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English (en)
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John Walter Keller Jr
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Cordis Corp
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Cordis Corp
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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
    • A61N1/368—Heart stimulators controlled by a physiological parameter, e.g. heart potential comprising more than one electrode co-operating with different heart regions

Definitions

  • a cardiac pacer which includes a pulse generating source and a ventricular electrode for applying the pulses as stimuli to the heart also includes means for sensing a heart potential by which the pulse generating circuitry will operate in response to the sensed heart potentials.
  • the pulse generating source comprises a free running multivibrator with an R-C cross coupling path from the collector of each transistor to the base of the other transistor.
  • Incoming signals corresponding to a sensed heart potential are connected to a diode which, when not reversely biased, passes them to the base of one of the transistors to recycle the multivibrator.
  • a capacitor and a charging and discharging circuit maintain the diode reversely biased for a simulated refractory delay period following the delivery of each heart stimulating pulse and/ or sensed heart potential pulse.
  • the means for sensing a heart potential may include both an atrial electrode and the ventricular electrode with switching means to select either for controlling the pacer.
  • This invention deals with cardiac pacers.
  • Among its objects are to simplify the construction of an electronic cardiac pacer, to accept a Wider range of natural physiological signals from the heart and take appropriate action, to give the attending physician a wider range of choice of modes of operation, and to ensure against failure of operation of the pacer, which might otherwise result from extraneous disturbing influences.
  • the left auricle accepts oxygenated blood from the lungs and delivers it to the left ventricle which pumps it through the body tissues.
  • the right auricle accepts de-oxygenated blood from the veins and delivers it to the right ventricle which pumps it through the lungs where the products of the body metabolism, notably carbon dioxide, are removed and oxygen is absorbed.
  • each side of the normal heart operates as a two-stage pump, the two auricles which together constitute the atrium contracting simultaneously and the two ventricles contracting simultaneously.
  • Contraction of the atrium is accompanied and slightly preceded by a transient electrochemical potential known in medical terminology as the P Wave.
  • AV atrioventricular
  • QRS complex another electrical potential known as the QRS complex normally appears in the ventricle and, in the normal heart, this initiates the contraction of the ventricle.
  • the refractory period which, in the human heart endures for about one-quarter second.
  • a vulnerable period of the heart of a few milliseconds duration in which, if an electrical stimulus is applied to the heart, though it does not respond by contraction, it may be damaged.
  • the artificial stimulus is generated by a multivibrator comprising two transistors of like conductivity types having cross couplings from the collector of each to the base of other such that, in the absence of a signal picked up from the atrium, it runs at a pre-set rate, illustratively 70 pulses per minute.
  • This multivibrator is characterized by an ON time when one of the transistors conducts and an OFF time when the other transistor conducts. Its full period is the sum of the ON time and the OFF time, and one or other of the transistors conducts throughout the full period.
  • the multivibrator can accept a signal, if present, from the AV delay simulator and this acts to switch the multivibrator into its ON state, perhaps earlier than if it were left to itself.
  • the multivibrator is insensitive to such a signal.
  • the ON time is the electronic counterpart of the refrectory period of the heart.
  • the ON time is determined solely by the magnitude of the circuit elements.
  • the OFF time is, in the absence of a signal from the atrium, similarly determined by other circuit elements but can be shortened when an atrial signal reaches the multivibrator through the AV delay simulator.
  • the pulsing takes place at a pre-set fixed rate while in the presence of atrial signals it takes place in synchronism with them, albeit retarded by the AV delay.
  • a regenerative amplifier which, in response to the switching of the multivibrator from its OFF state to its ON state, delivers a brief pulse, of a few milliseconds duration. This is passed through a direct current blocking capacitor to an electrode which is surgically embedded in the heart muscle.
  • this is accomplished by the inclusion of a switch which, in one position accepts the P-Wave from the atrium as in the specification referred to above, and in the other position accepts only QRS complexes from the ventricle.
  • the electrode which senses the QRS complex may be the same one which has already been imbedded in the heart muscle and by which the contraction-initiating stimulus is delivered to it.
  • the potential thus picked up from the heart i.e., P-Wave or QRS complex
  • a multivibrator which, in the absence of sensed heart potentials, delivers contraction-promoting stimuli to the ventricle at a pre-set rate, e.g., 7O stimuli per minute.
  • the potential-thus sensed and delayed acts to switch the multivibrator from its OFF state to its ON state in which it delivers a stimulating pulse to the heart.
  • QRS complex When the sensed potential is that of a QRS complex then, the heart muscle having just undergone a contraction in the normal physiological fashion in response to its own QRS complex, the artificial stimulus falls within the refractory period of the heart and is thus ineffective to cause a premature contraction. If, to the contrary, an abnormally long time has elapsed since the sensing of the last QRS complex, the multivibrator delivers an artificial stimulus to the ventricle which responds by contracting. Every such stimulated contraction is accompanied by a potential change in the heart which is known, in medicine, as a QRS complex. To avoid confusion the term QRS complex is employed in this specification to denote only a natural physiologic signal in contrast to one that is artificially stimulated.
  • the stimulus required by the ventricle to initiate its contraction is very brief: its duration may be as short as a millisecond or so. This is in sharp contrast to the much longer interval (0.85 second for a pulse rate of 70 beats per minute) which elapses between successive stimuli.
  • a pulse source of very short duty cycle a multivibrator of which the ON time is 12 milliseconds while the OFF time, in the free-running condition, is about 0.85 second.
  • the multivibrator employs two transistors of opposite conductivity types. During the brief ON time, both transistors conduct. During the much longer OFF time, neither conducts. In addition to combining the functions of two components of the earlier apparatus, this approach conserves battery power and prolongs battery life.
  • the simulated refractory delay time was provided by the OFF time of one transistor and the ON time of the other.
  • a reverse bias on a diode initiated by the outgoing pulse.
  • This bias gradually decays during the interpulse interval.
  • this reverse bias falls, in the required refractory time of about 0.3 seconds, to a level at which it is no greater than the amplitude of a pulse from the AV delay simulator whereupon, though not earlier, this pulse is passed by the back-biased diode to the multivibrator, thus to cause generation of a new heart-stimulating pulse.
  • a signal which may be picked up by an electrode implanted in, on, or near the atrium of the heart passes through a switch S, when the latter is in position B, through a filter resistor R and capacitors C C to the input point of a two-stage amplifier of conventional construction including transistors Q and Q with conventional interconnections among them.
  • Power and bias are supplied to this amplifier and to other component parts of the apparatus, by sections B 8 of a battery.
  • each battery 'section is a mercury cell, and each one contributes about 14 volts.
  • a Zener diode Z1 having a breakdown potential of about 3 volts is included to protect the circuit against spurious voltages of excessive magnitudes.
  • the filter excludes components of about 10 c.p.s. and lower and of about 200 c.p.s. and higher. Moreover it introduces a slight delay.
  • This signal after being slightly delayed by the filter.
  • the incoming signal from the amplifier is applied to the base of Q through a diode D and to the base of the transistor Q thorugh a diode D These two diodes are oppositely poled so that the incoming amplified signal shall switch the monostable multivibrator from its stable state to its metastable state independently of the polarity of the signal.
  • the anode of D and the cathode of D are returned through R to a suitable point of a voltage divider constituted of R and R connected across battery sections B and B This ensures freedom for the signal applied to the diodes to swing either positively or negatively with equal sensitivity.
  • a positive signal is applied through the diode D to the base of transistor Q while a negative signal is similarly applied through the diode D to the base of transistor Q
  • the action in either case, is to shift the monostable multi vibrator to its metastable state. This construction relieves the surgeon of the need to implant the atrial pickup electrode in a particular part of the heart at which the wave to be sensed is known to be of preassigned polarity.
  • the monostable multivibrator Each time the monostable multivibrator is thus shifted from its stable state to its metastable state it delivers a positive pulse a, and hence a positive spike signal b through a capacitor C Were it not for the diode D this signal would be delivered to the free-running multivibrator constituted of transistors Q and Q But because of the fashion in which this diode is connected and poled, this positive signal is blocked by the diode D and is thus ineffective to alter the state of the free-running multivibrator.
  • the present free-running multivibrator employs complementary transistors; i.e., transistors of opposite conductivity types. Hence, when the transistor Q commences to conduct then, through regenerative action,
  • the transistor Q commences to conduct too, through a diode D
  • This diode, poled as shown, is included merely to protect the transistor Q,- from reverse voltages. Conduction of these two transistors endures for a pre-set time, determined by the magnitudes of C and R illustratively about two milliseconds. This period is appropriately termed the CN time of the multivibrator.
  • the multivibrator then returns by itself to its OFF state in which both of the transistors remain non-conductive for the duration of the interpulse interval, more or less, depending on whether, in the absence of a signal through the capacitor C it runs free at the pre-set rate of about 70 beats per minute, which means an interpulse interval of about 0.85 second, or whether its switching is advanced on the time scale by a signal picked up from the heart, amplified, delayed by the AV delay simulator, and applied to the multivibrator Q -Q through the diode D thus to shorten a particular interpulse interval.
  • the duration of the intrinsic (not externally influenced) interpulse interval is determined by the magnitudes of C and of R 5,
  • R R and R of which R is the dominant one may be variable, thus to alter the intrinsic interpulse interval.
  • the output pulse of the free-running multivibrator (Q Q appears as a voltage drop across the resistors R and R A tap 2 picks up a preassigned fraction of this voltage and delivers it to the baSe electrode of a power transistor Q which then conducts, permitting current to flow from the positive terminal of the battery stack, through a bias resistor R to the negative battery terminal.
  • the voltage appearing across the bias-resistor R is passed by way of a blocking capacitor C to an electrode 3 im-bedded in or near the ventricle of the heart.
  • the electrical circuit is completed through another electrode 4 located in the patients abdomen or chest cavity. This may advantageously be a metal shield which surrounds the implanted apparatus.
  • the resistors R and R are preferably of a magnitude to provide a constant current output.
  • a capacitor C interconnects the tap 2 with the negative battery terminal. It serves merely to bypass small, accidental transient voltages and so to prevent their operating the power transistor Q
  • the diode D can pass such a negative signal to the base of Q causing a shift of the state of the multivibrator, Q Q both transistors Q and Q becoming conductive, thus advancing the next multivibrator output pulse on the time scale.
  • a patient requires an artificial heat pacer, electronic or otherwise, only when the physiological behavior of his heart is, at best, doubtful.
  • the P-Wave recovered by the atrial electrode may at any time fail or become unreliable in which case the apparatus described in the specification referred to above can operate only at its pre-set rate, for example, beats per minute or at undesirable P-Wave rates.
  • the atrial signal fails the ventricle may still be in condition to deliver a spontaneous sensible QRS complex which may, indeed, cause a contraction of the ventricle in the normal physiologic fashion.
  • the ventricle may undergo contractions under the influence of two unrelated stimuli; first, its own physiologic contractions induced by its own QRS complexes and second, the stimulated contractions induced by the pacer apparatus, now running at its pre-set rate.
  • the result may be a very troublesome cardiac arrythmia.
  • this difliculty is prevented by switching the input point of the amplifier from the atrial electrode 1 to the ventricular electrode 3, that is to say by throwing the switch S from position B to position A.
  • any QRS complex picked up by the ventricular electrode 3 and following the last sensed ventricular potential, QRS complex or stimulus, by more than the simulated refractory period is amplified, passed through the AV delay simulator, and applied to the free-running multivibrator Q Q This causes the multivibrator immediately to switch from its OFF state to its ON state.
  • the pulse from the AV delay simulator is blocked by the diode D
  • the free-running multivibrator Q -Q is thus switched, its output pulse is delivered as a stimulus to the ventricle electrode 3 in the fashion described above. Because the delay interposed by the AV delay simulator is of the order of A second, while the refractory period of the heart itself, following its last preceding contraction, is of the order of one-quarter second, the stimulus thus delivered by the multivibrator in response to a natural sensed QRS complex reaches the heart during the hearts own physiological refractory period and is thus ineffective to initiate a contraction.
  • each pacer stimulus is picked up "by this electrode 3 and, when the switch is in position A, amplified, and applied to the monostable multivibrator (Q -Q If, and only if, the latter is in its stable state, a pulse is passed on, after the termination of the simulated AV delay, to the diode D If, and only if, the latter is in its non-refractory state, this pulse trips the free-running multivibrator Q Q causing it to generate a new pulse and deliver it as a stimulus to the heart. If, when the heart potential is sensed, the monostable multivibrator (Q Q is in its metastable state,
  • the sensed heart potential is blocked at this point of the circuit, If it passes this point, it may still be blocked by the diode D if in its refractory state.
  • This arrangement ensures that, even though extraneous interfering influences may be sensed, either by the atrial electrode 1 or by the ventricular electrode 3, no two consecutive stimuli can be delivered to the heart unless they are spaced apart on the time scale by 0.4 second.
  • a reed switch may be employed having a small margin of mechanical stability in each of two different positions. This stability may be imparted by a suitable bias, e.g., a magnetic bias.
  • the switch S may then be thrown from either position to the other by the field of an external magnet which, when the magnet is brought close to the pacer, threads the body wall and tissues and actuates the switch,
  • a thermally-controlled switch may be employed, or one that responds to radio frequency or video frequency pulses, or even to a mechanical shock.
  • a cardiac pacer comprising a source adapted to generate electric pulses at a preassigned repetition rate conformable to the rate of the normal heart beat of a patient, means including a ventricular electrode for applying said pulses as stimuli to said heart, means for sensing a heart potential, said pulse source comprising a freerunning transistor multivibrator and an R-C cross coupling path extending from the collector of each transistor is the base of the other transistor whereby said source, absent an incoming physiologic potential, generates a periodic sequence of pulses separated by interpulse intervals, and means under control of said heart potential for advancing the next source pulse on the time scale, thus to initiate a new source period, said advancing means including a diode disposed to receive an incoming signal, and, when not reversely biased, to pass said signal to the base of one of said transistors to advance the next free running pulse due from said multivibrator source on the time scale, a supplementary biasing capacitor, connections for charging said supplementary capacitor to a preassigned potential on the occurence

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  • Health & Medical Sciences (AREA)
  • Cardiology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biophysics (AREA)
  • Physiology (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Electrotherapy Devices (AREA)
US548239A 1966-05-06 1966-05-06 Multimode cardiac pacer Expired - Lifetime US3433228A (en)

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DE (1) DE1589600A1 (fr)
FR (1) FR1515162A (fr)
GB (1) GB1108858A (fr)
NL (1) NL163722C (fr)
SE (1) SE327023B (fr)

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3593718A (en) * 1967-07-13 1971-07-20 Biocybernetics Inc Physiologically controlled cardiac pacer
US3595242A (en) * 1969-03-26 1971-07-27 American Optical Corp Atrial and ventricular demand pacer
DE2112583A1 (de) * 1970-03-24 1971-11-18 Zacouto Fred Dr Med Verfahren zur Feststellung,Steuerung und Beeinflussung des Wertes von Lebensfunktionen,insbesondere des Herzens,bei Menschen und Saeugetieren und Vorrichtung zur Durchfuehrung dieses Verfahrens
US3648707A (en) * 1969-07-16 1972-03-14 Medtronic Inc Multimode cardiac paces with p-wave and r-wave sensing means
US3661158A (en) * 1969-12-15 1972-05-09 American Optical Corp Atrio-ventricular demand pacer with atrial stimuli discrimination
US3688776A (en) * 1969-10-13 1972-09-05 Devices Ltd Demand cardiac pacer with fast rate for indicating interference
US3718142A (en) * 1971-04-23 1973-02-27 Medtronic Inc Electrically shielded, gas-permeable implantable electro-medical apparatus
US3747604A (en) * 1969-12-15 1973-07-24 American Optical Corp Atrial and ventricular demand pacer with separate atrial and ventricular beat detectors
US3867949A (en) * 1973-04-27 1975-02-25 Cardiac Pacemakers Inc Cardiac pacer with voltage doubler output circuit
US3881494A (en) * 1973-05-22 1975-05-06 Jr James M Paul Electro pulse arthritic physiotherapy system
US3898994A (en) * 1971-01-26 1975-08-12 Arco Nuclear Co Fixed-rate pacer circuit with self-starting capability
US3903897A (en) * 1972-03-11 1975-09-09 Kent Cambridge Medical Ltd Cardiac pacer
US3937226A (en) * 1974-07-10 1976-02-10 Medtronic, Inc. Arrhythmia prevention apparatus
US3949759A (en) * 1975-05-05 1976-04-13 Research Corporation Cardiac pacing apparatus
US4031899A (en) * 1976-01-22 1977-06-28 Vitatron Medical B.V. Long life cardiac pacer with switching power delivery means and method of alternately delivering power to respective circuit portions of a stimulus delivery system
US4091817A (en) * 1976-09-27 1978-05-30 American Optical Corporation P-Wave control, R-wave inhibited ventricular stimulation device
US4108148A (en) * 1976-11-03 1978-08-22 Sheldon Thaler Pacer with automatically variable A-V interval
WO1979000070A1 (fr) * 1977-07-27 1979-02-22 S Joseph Stimulateur cardiaque
US4202341A (en) * 1977-03-19 1980-05-13 Biotronik Mess- Und Therapiegerate Gmbh & Co. Cardiac pacemaker circuit with variable operation
US4248238A (en) * 1979-03-26 1981-02-03 Joseph Simon P Heart stimulating apparatus
EP0037737A2 (fr) * 1980-04-07 1981-10-14 Medtronic, Inc. Entraineur à la demande avec rejet des impulsions parasitaires causées par les impulsions de sortie
US4307725A (en) * 1978-08-22 1981-12-29 Watfort Limited Apparatus for tachycardia investigation or control
US4335727A (en) * 1980-05-30 1982-06-22 Mcpherson William E Pacemaker assembly having ventricular inhibited and ventricular triggered pacemaker units
US4411268A (en) * 1982-02-10 1983-10-25 Medtronic, Inc. Muscle stimulator
US4705043A (en) * 1985-07-05 1987-11-10 Mieczslaw Mirowski Electrophysiology study system using implantable cardioverter/pacer
US4729376A (en) * 1985-05-28 1988-03-08 Cordis Corporation Cardiac pacer and method providing means for periodically determining capture threshold and adjusting pulse output level accordingly
US4958632A (en) * 1978-07-20 1990-09-25 Medtronic, Inc. Adaptable, digital computer controlled cardiac pacemaker
US20050021096A1 (en) * 2003-07-24 2005-01-27 Mirowski Family Ventures, L.L.C. Methods, apparatus, and systems for multiple stimulation from a single stimulator
US20050055057A1 (en) * 2003-09-05 2005-03-10 Mirowski Famliy Ventures, L.L.C. Method and apparatus for providing ipselateral therapy
US20050055058A1 (en) * 2003-09-08 2005-03-10 Mower Morton M. Method and apparatus for intrachamber resynchronization
USRE39897E1 (en) 1989-01-23 2007-10-23 Mirowski Family Ventures, L.L.C. Method and apparatus for treating hemodynamic disfunction

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2097337A6 (fr) * 1970-03-24 1972-03-03 Zacouto Fred
FR2471789A1 (fr) * 1979-12-18 1981-06-26 Cardiofrance Co Stimulateur cardiaque implantable polyvalent et procede d'utilisation de ce stimulateur

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB826766A (en) * 1956-12-06 1960-01-20 Nat Res Dev Device for stimulating periodic functions of the body
US3311111A (en) * 1964-08-11 1967-03-28 Gen Electric Controllable electric body tissue stimulators
US3345990A (en) * 1964-06-19 1967-10-10 American Optical Corp Heart-beat pacing apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB826766A (en) * 1956-12-06 1960-01-20 Nat Res Dev Device for stimulating periodic functions of the body
US3345990A (en) * 1964-06-19 1967-10-10 American Optical Corp Heart-beat pacing apparatus
US3311111A (en) * 1964-08-11 1967-03-28 Gen Electric Controllable electric body tissue stimulators

Cited By (42)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3593718A (en) * 1967-07-13 1971-07-20 Biocybernetics Inc Physiologically controlled cardiac pacer
US3595242A (en) * 1969-03-26 1971-07-27 American Optical Corp Atrial and ventricular demand pacer
US3648707A (en) * 1969-07-16 1972-03-14 Medtronic Inc Multimode cardiac paces with p-wave and r-wave sensing means
US3688776A (en) * 1969-10-13 1972-09-05 Devices Ltd Demand cardiac pacer with fast rate for indicating interference
US3747604A (en) * 1969-12-15 1973-07-24 American Optical Corp Atrial and ventricular demand pacer with separate atrial and ventricular beat detectors
US3661158A (en) * 1969-12-15 1972-05-09 American Optical Corp Atrio-ventricular demand pacer with atrial stimuli discrimination
DE2112583A1 (de) * 1970-03-24 1971-11-18 Zacouto Fred Dr Med Verfahren zur Feststellung,Steuerung und Beeinflussung des Wertes von Lebensfunktionen,insbesondere des Herzens,bei Menschen und Saeugetieren und Vorrichtung zur Durchfuehrung dieses Verfahrens
US3898994A (en) * 1971-01-26 1975-08-12 Arco Nuclear Co Fixed-rate pacer circuit with self-starting capability
US3718142A (en) * 1971-04-23 1973-02-27 Medtronic Inc Electrically shielded, gas-permeable implantable electro-medical apparatus
US3903897A (en) * 1972-03-11 1975-09-09 Kent Cambridge Medical Ltd Cardiac pacer
US3867949A (en) * 1973-04-27 1975-02-25 Cardiac Pacemakers Inc Cardiac pacer with voltage doubler output circuit
US3881494A (en) * 1973-05-22 1975-05-06 Jr James M Paul Electro pulse arthritic physiotherapy system
US3937226A (en) * 1974-07-10 1976-02-10 Medtronic, Inc. Arrhythmia prevention apparatus
US3949759A (en) * 1975-05-05 1976-04-13 Research Corporation Cardiac pacing apparatus
US4031899A (en) * 1976-01-22 1977-06-28 Vitatron Medical B.V. Long life cardiac pacer with switching power delivery means and method of alternately delivering power to respective circuit portions of a stimulus delivery system
US4091817A (en) * 1976-09-27 1978-05-30 American Optical Corporation P-Wave control, R-wave inhibited ventricular stimulation device
US4108148A (en) * 1976-11-03 1978-08-22 Sheldon Thaler Pacer with automatically variable A-V interval
US4202341A (en) * 1977-03-19 1980-05-13 Biotronik Mess- Und Therapiegerate Gmbh & Co. Cardiac pacemaker circuit with variable operation
WO1979000070A1 (fr) * 1977-07-27 1979-02-22 S Joseph Stimulateur cardiaque
US4958632A (en) * 1978-07-20 1990-09-25 Medtronic, Inc. Adaptable, digital computer controlled cardiac pacemaker
US5318593A (en) * 1978-07-20 1994-06-07 Medtronic, Inc. Multi-mode adaptable implantable pacemaker
US4307725A (en) * 1978-08-22 1981-12-29 Watfort Limited Apparatus for tachycardia investigation or control
US4248238A (en) * 1979-03-26 1981-02-03 Joseph Simon P Heart stimulating apparatus
EP0037737A2 (fr) * 1980-04-07 1981-10-14 Medtronic, Inc. Entraineur à la demande avec rejet des impulsions parasitaires causées par les impulsions de sortie
EP0037737A3 (en) * 1980-04-07 1981-12-30 Medtronic, Inc. Demand pacemaker with output pulse artifact rejection
US4335727A (en) * 1980-05-30 1982-06-22 Mcpherson William E Pacemaker assembly having ventricular inhibited and ventricular triggered pacemaker units
US4411268A (en) * 1982-02-10 1983-10-25 Medtronic, Inc. Muscle stimulator
US4729376A (en) * 1985-05-28 1988-03-08 Cordis Corporation Cardiac pacer and method providing means for periodically determining capture threshold and adjusting pulse output level accordingly
US4705043A (en) * 1985-07-05 1987-11-10 Mieczslaw Mirowski Electrophysiology study system using implantable cardioverter/pacer
USRE39897E1 (en) 1989-01-23 2007-10-23 Mirowski Family Ventures, L.L.C. Method and apparatus for treating hemodynamic disfunction
US7231249B2 (en) 2003-07-24 2007-06-12 Mirowski Family Ventures, L.L.C. Methods, apparatus, and systems for multiple stimulation from a single stimulator
US20070208387A1 (en) * 2003-07-24 2007-09-06 Mirowski Family Ventures, L.L.C. Methods, apparatus, and systems for multiple stimulation from a single stimulator
US20050021096A1 (en) * 2003-07-24 2005-01-27 Mirowski Family Ventures, L.L.C. Methods, apparatus, and systems for multiple stimulation from a single stimulator
US8249725B2 (en) 2003-07-24 2012-08-21 Mirowski Family Ventures, L.L.C. Methods, apparatus, and systems for multiple stimulation from a single stimulator
US8761905B2 (en) 2003-07-24 2014-06-24 Mirowski Family Ventures, L.L.C. Methods, apparatus, and systems for multiple stimulation from a single stimulator
US9566444B2 (en) 2003-07-24 2017-02-14 Mirowski Family Ventures, L.L.C. Methods, apparatus, and systems for multiple stimulation from a single stimulator
US20050055057A1 (en) * 2003-09-05 2005-03-10 Mirowski Famliy Ventures, L.L.C. Method and apparatus for providing ipselateral therapy
US20070191893A1 (en) * 2003-09-05 2007-08-16 Mirowski Family Ventures, L.L.C. Method and apparatus for providing ipselateral therapy background
US8744558B2 (en) 2003-09-05 2014-06-03 Mirowski Family Ventures, L.L.C. Method and apparatus for providing ipselateral therapy
US20050055058A1 (en) * 2003-09-08 2005-03-10 Mower Morton M. Method and apparatus for intrachamber resynchronization
US9901739B2 (en) 2003-09-08 2018-02-27 Mirowski Family Ventures, LLC Method and apparatus for intrachamber resynchronization
US11207524B2 (en) 2003-09-08 2021-12-28 Mirowski Family Ventures, LLC Method and apparatus for intrachamber resynchronization

Also Published As

Publication number Publication date
DE1589600A1 (de) 1970-05-06
NL6700343A (fr) 1967-11-07
GB1108858A (en) 1968-04-03
NL163722C (nl) 1980-10-15
SE327023B (fr) 1970-08-10
NL163722B (nl) 1980-05-16
FR1515162A (fr) 1968-03-01

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