Apparatus for combining pacing and cardioverting functions in a single implanted device

• US 4,440,172 A
• Filed: 12/11/1980
• Issued: 04/03/1984
• Est. Priority Date: 10/02/1980
• Status: Expired due to Term

• Current Assignee: Mirowski Family Ventures LLC
• Original Assignee: Mieczyslaw Mirowski
• Inventors: Langer, Alois A.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/215,520
• Time in Patent Office: 1,209 Days
• Field of Search: 128/419 PG, 128/419 D, 128/696, 128/697, 128/902, 128/908
• US Class Current: 607/4
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: Y10S 128/908 Patient protection from electric shock

Abstract

The invention relates to an apparatus for combining pacing and cardioverting functions in a single implanted device, circuitry being provided not only to interface the defibrillator to the ECG amplifier and other elements of the device, but also to provide protection of the ECG amplifier from the defibrillator output pulses, from loading by the defibrillator itself, and from overloading by externally generated defibrillator pulses. A specific embodiment of the invention combines a defibrillator, a pacer and an ECG amplifier in a single implanted device utilizing two terminal-electrode lead combinations for connection to the patient, while further embodiments employ three and four terminal-electrode lead combinations. The invention employs a high-frequency transformer coupling technique for pacing, or, alternatively, high-frequency transformer coupling with modulation-demodulation. Moreover, in accordance with the invention, overloading of the ECG amplifier is prevented by provision of (in one embodiment) series-connected and oppositely oriented zener diodes, and (in a second embodiment) parallel-connected diodes in series with a blocking capacitor for blocking DC voltage.

Claims

1. An implantable defibrillation system for implantation in a patient comprising a ground reference, defibrillating means for generating high-voltage defibrillating pulses, an ECG amplifier for sensing cardiac signals, common conductor means electrically connected to both said defibrillating means and said ECG amplifier for transferring both defibrillating pulses and cardiac signals respectively to and from said patient through said ground reference, said defibrillating means being connected to said common conductor means, and interface means being electrically connected to said amplifier and said common conductor means for limiting the voltage applied to said amplifier during the presence of a defibrillating pulse and for transferring a substantial portion of said cardiac signal to said amplifier during the absence of a defibrillating pulse.

2. The system of claim 1, wherein said interface means includes impedance means and at least one pair of series-connected, oppositely poled diode means connected in series between said common conductor means and said reference thereby to form an impedance-diode network, said network being responsive to said defibrillating pulse to produce thereacross a substantial portion of the voltage appearing on said conductor means during the presence of a defibrillating pulse while simultaneously minimizing the voltage applied to said amplifier;

and during the absence of a defibrillating pulse, said network being responsive to receive thereacross a substantial portion of the voltage signal appearing on said conductor means and to provide said voltage signal to said amplifier.

3. The system of claim 1, wherein said interface means includes impedance means connected in series with at least one pair of oppositely poled, parallel-connected diode means, said impedance means and diode means being connected between said common conductor means and said ground reference, said impedance means being responsive to said defibrillating pulse to produce thereacross a substantial portion of the voltage appearing on said conductor means during the presence of a defibrillating pulse while simultaneously minimizing the voltage applied to said amplifier, and during the absence of a defibrillating pulse, said diode means being responsive to receive thereacross a substantial portion of the voltage signal appearing on said conductor means and to provide said voltage to said amplifier.

4. The system of claim 3, wherein said interface means further comprises isolation means interposed between said common conductor means and said ECG amplifier for isolating said ECG amplifier from DC voltage.

5. The system of claim 1, further comprising triggering means for providing trigger pulses and a trigger circuit connected to said defibrillator being responsive to said trigger pulses for passing said defibrillation pulses over said common conductor means to said patient.

6. The system of claim 5, wherein said trigger circuit comprises a rectifier having a control lead, said rectifier being actuated by said trigger pulses to pass said defibrillation pulses.

7. The system of claim 6, wherein said rectifier is an optically controlled rectifier, and further includes a photodiode connected to said triggering means responsive to said trigger pulses for activating said optically controlled rectifier, said optically controlled rectifier being responsive thereto for activating said rectifier via said control lead thereof to pass said defibrillation pulses.

8. The system of claim 2 wherein said diode reans comprise zener diodes.

9. An implantable defibrillation system for implantation in a patient comprising a ground reference, a defibrillator for generating high-voltage defibrillating pulses, an ECG amplifier for sensing cardiac signals, common conductor means electrically connected to both said defibrillating means and said ECG amplifier for transferring both defibrillating pulses and cardiac signals respectively to and from said patient through said ground reference, said amplifier means being connected to said common conductor means for receiving said cardiac signals, and defibrillator interface means being electrically connected to said defibrillator and said common conductor means for prevention said defibrillator from loading said ECG amplifier while said defibrillation system is implanted in said patient.

10. The system of claim 9, wherein said prevention means comprises a resistor connected between said defibrillator and said ground reference, said connection of said resistor to said defibrillator forming a junction, said defibrillation interface means further comprising a diode connected between said junction and said ECG amplifier.

11. The system of claim 9, further comprising triggering means for providing trigger pulses and a trigger circuit connected to said defibrillator being responsive to said trigger pulses for passing said defibrillation pulses over said common conductor means to said patient.

12. The system of claim 11, wherein said trigger circuit comprises a rectifier having a control lead, said rectifier being actuated by said trigger pulses to pass said defibrillation pulses.

13. The system of claim 12, wherein said rectifier is an optically controlled rectifier, and a photodiode connected to said triggering means is responsive to said trigger pulses for activating said optically controlled rectifier, said optically controlled rectifier being responsive thereto for activating said rectifier via said control lead thereof to pass said defibrillation pulses.

14. An implantable defibrillation system for implantation in a patient comprising a ground reference, a defibrillator for generating defibrillating pulses, an ECG amplifier for sensing cardiac signals, common conductor means electrically connected to both said defibrillating means and said ECG amplifier for transferring both defibrillating pulses and cardiac signals respectively to and from said patient through said ground reference, said amplifier means being connected to said conductor means, for receiving cardiac signals, and defibrillator protection means being electrically connected to said defibrillator and said common conductor means for protecting said defibrillator from externally applied defibrillating pulses applied to said patient while said implantable defibrillation system is implanted in said patient.

15. The system of claim 14, wherein said protection means comprises a diode connected between said defibrillator and said patient.

16. The system of claim 14, further comprising triggering means for providing trigger pulses and a trigger circuit connected to said defibrillator being responsive to said trigger pulses for passing said defibrillation pulses over said common conductor means to said patient.

17. The system of claim 16, wherein said trigger circuit comprises a rectifier having a control lead, said rectifier being actuated by said trigger pulses to pass said defibrillation pulses.

18. The system of claim 17, wherein said defibrillator protection means further includes an optically controlled rectifier, and a photodiode connected to said triggering means and responsive to said trigger pulses for activating said optically controlled rectifier, said optically controlled rectifier being responsive thereto for activating said rectifier via said control lead thereof to pass said defibrillation pulses.

19. A combined defibrillator-pacer system for implantation in a patient and for selectively defibrillating and pacing the patient, said system comprising a ground reference, defibrillator means for generating high-voltage defibrillation pulses, a pacer connected, in parallel with said defibrillator means for generating pacing pulses, an electrocardiograph (ECG) amplifier for sensing cardiac signals and being connected in parallel with said defibrillator means and said pacer, common conductor means electrically connected to both said defibrillating means and said ECG amplifier for transferring both defibrillating pulses and cardiac signals respectively to and from said patient through said ground reference, said defibrillating means being connected to said common conductor means, and interface means being electrically connected to said amplifier and said common conductor means for limiting the voltage applied to said amplifier during the presence of a defibrillating pulse and for transferring a substantial portion of said cardiac signa1 to said amplifier durinq the absence of a defibrillating pulse.

20. The system of claim 19, wherein said interface means include impedance means and at least one pair of series-connected, oppositely poled diode means connected in series between said common conductor means and said ground reference thereby to form an impedance-diode network, said network being responsive to said defibrillating pulse to produce thereacross a substantial portion of the voltage appearing on said conductor means during the presence of a defibrillating pulse while simultaneously minimizing the voltage applied to said amplifier, and durinq the absence of a defibrillating pulse, said network being responsive to receive thereacross a substantial portion of the voltage signal appearing on said conductor means and to provide said voltage signal to said amplifier.

21. The system in claim 19, wherein said interface means includes impedance means connected in series with at least one pair of oppositely poled, parallel-connected diode means, said impedance means and diode means being connected between said common conductor means and said ground reference, said impedance means being responsive to said defibrillating pulse to produce thereacross a substantial portion of the voltage appearing on said conductor means during the presence of a defibrillating pulse while simultaneously minimizing the voltage applied to said amplifier, and during the absence of a defibrillating pulse, said diode means being responsive to receive thereacross a substantial portion of the voltage signal appearing on said conductor means and to provide said voltage to said amplifier.

22. The system of claim 21, wherein said interface means further comprises isolating means interposed between said common conductor means and said ECG amplifier for isolating said ECG amplifier from DC voltage.

23. The system of claim 19, wherein said patient is equipped with first and second electrodes and a pacing tip, said system further comprising first connection means for connecting said defibrillator means, said pacer, and said ECG amplifier to said first electrode and said pacing tip, and second connection means for connecting said second electrode to said electrical ground.

24. The system in claim 23, wherein said first connection means comprises a forward-biased diode to permit defibrillation of said patient.

25. The system in claim 23, wherein said first connection means comprises a parallel resistor-diode arrangement for permitting pacing of said patient, said arrangement for including a reverse-biased diode and a resistor of high impedance for protecting said pacing tip from said defibrillation pulses.

26. The system in claim 19, further comprising triggering means for providing trigger pulses, said interface means including a trigger circuit connected to said defibrillator means and responsive to said trigger pulses for passing said defibrillation pulses over said common conductor means to said patient.

27. The system in claim 26, wherein said trigger circuit comprises a rectifier having a control lead, said rectifier being actuated by said trigger pulses to pass said defibrillation pulses.

28. The system in claim 26, wherein said interface means further includes an optically controlled rectifier, and a photodiode connected to said triggering means and responsive to said trigger pulses for activating said optically controlled rectifier, said optically controlled rectifier being responsive thereto for activating said rectifier via said control lead thereof to pass said defibrillation pulses.

29. A combined defibrillator-pacer system for implantation in a patient and for selectively defibrillating and pacing the patient, said system comprising a ground reference, defibrillator means for generating high-voltage defibrillation pulses, a pacer connected in parallel with said defibrillator means for generating pacing pulses, an electrocardiograph (ECG) amplifier for sensing cardiac signals and being connected in parallel with said defibrillator means and said pacer, common conductor means electrically connected to both said defibrillator means and said ECG amplifier for transferring both defibrillating pulses and cardiac signals respectively to and from said patient through said ground reference, said amplifier means being connected to said common conductor means for receiving said cardiac signals, and defibrillator interface means being electrically connected to said defibrillator means and said common conductor means for preventing said defibrillator means from loading said ECG amplifier while said defibrillation system is implanted in said patient.

30. The system of claim 29, wherein said interface means comprises a resistor connected between said defibrillator means and said electrical ground, said connection of said resistor to said defibrillator means forming a junction, said interface means further comprising a diode connected between said junction and said ECG amplifier.

31. The system of claim 30, wherein said interface means further comprises a tunnel diode connected between said junction and said diode.

32. The system of claim 29, wherein said patient is equipped with first and second electrodes and a pacing tip, said system further comprising first connection means for connecting said defibrillator means, said pacer, and said ECG amplifier to said first electrode and said pacing tip, and second connection means for connecting said second electrode to said electrical ground.

33. The system of claim 32, wherein said first connection means comprises a forward-biased diode to permit defibrillation of said patient.

34. The system of claim 32, wherein said first connection means comprises a parallel resistor-diode arrangement for permitting pacing of said patient, said arrangement including a reverse-biased diode and a resistor of high impedance for protecting said pacing tip from said defibrillation pulses.

35. The system of claim 29, further comprising triggering means for providing trigger pulses, said interface means including a trigger circuit connected to said defibrillator and responsive to said trigger pulses for passing said defibrillation pulses to said patient over said common conductor means.

36. The system of claim 35, wherein said trigger circuit comprises a rectifier having a control lead, said rectifier being actuated by said trigger pulses to pass said defibrillation pulses.

37. The system of claim 36, wherein said interface means further includes an optically controlled rectifier, and a photodiode connected to said providing means and responsive to said trigger pulses for activating said optically controlled rectifier, said optically controlled rectifier being responsive thereto for activating said rectifier via said control lead thereof to pass said defibrillation pulses.

38. A combined defibrillator-pacer system for implantation in a patient and for selectively defibrillating and pacing a patient, said system comprising a ground reference, defibrillator means for generating defibrillation pulses, a pacer connected in parallel with said defibrillator for generating pacing pulses, an electrocardiograph (ECG) amplifier for sensing cardiac signals and being connected in parallel with said defibrillator and said pacer, common conductor means electrically connected to both said defibrillating means and said ECG amplifier for transferring both defibrillating pulses and cardiac signals respectively to and from said patient through said ground reference, said amplifier means being connected to said conductor means for receiving cardiac signal, and defibrillator protection means being electrically connected to said defibrillator means and said common conductor means for protecting said defibrillator means from externally applied defibrillating pulses applied to said patient while said implantable defibrillation system is implanted in said patient.

39. The system in claim 38, wherein said protection means comprises a diode connected between said defibrillator means and said patient.

40. The system in claim 38, wherein said patient is equipped with first and second electrodes and a pacing tip, said system further comprising first connection means for connecting said defibrillator means said pacer, and said ECG amplifier to said first electrode and said pacing tip, and second connection means for connecting said second electrode to said electrical ground.

41. The system of claim 40, wherein said first connection means comprises a forward-biased diode to permit defibrillation of said patient.

42. The system of claim 41, wherein said first connection means comprises a parallel resistor-diode arrangement for permitting pacing of said patient, said arrangement including a reverse-biased diode and a resistor of high impedance for protecting said pacing tip from said defibrillation pulses.

43. The system of claim 38, further comprising triggering means for providing trigger pulses, said protection means including a trigger circuit connected to said defibrillator means and responsive to said trigger pulses for passing said defibrillation pulses to said patient over said common conductor means.

44. The system of claim 43, wherein said trigger circuit comprises a rectifier having a control lead, said rectifier being actuated by said trigger pulses to pass said defibrillation pulses.

45. The system of claim 44, wherein said protection means further includes an optically controlled rectifier, and a phtodiode connected to said providing means and responsive to said trigger pulses for activating said optically controlled rectifier, said optically controlled rectifier being responsive thereto for activating said rectifier via said control lead thereof to pass said defibrillation pulses.