Programmable body stimulator

• US 4,066,086 A
• Filed: 09/13/1976
• Issued: 01/03/1978
• Est. Priority Date: 06/05/1975
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Alferness, Clifton A., Adams, John M.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/722,626
• Time in Patent Office: 477 Days
• Field of Search: 128/419 C, 128/419 E, 128/419 P, 128/419 PG, 128/419 R, 128/420, 128/421, 128/422, 128/423
• US Class Current: 607/59
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: A61N 1/37217 characterised by the communication link, e.g. acoustic or tactile
• CPC Class Codes: A61N 1/37223 Circuits for electromagnetic coupling

Abstract

A body implantable device for providing electrical stimulation to living animal tissue. The device includes a pulse generator having at least one alterable output parameter and circuitry responsive to first externally generated signals for altering the alterable output parameter in predetermined correspondence with the number of said first signals. The output parameter altering circuitry is enabled only during the occurrence of second signals having characteristics discriminable from the characteristics of the first signals. In a preferred embodiment, the first signals are pulses of radio frequency energy and the second signals are magnetic. The invention may be embodied in a cardiac pacemaker of either the asynchronous or demand type and the second signals may be employed to cause a demand cardiac pacemaker to revert to an asynchronous operation.

Claims

1. In a body-implantable device for providing electrical stimulation to living animal tissue of the type having pulse generator means with at least one alterable output parameter, output means adapted for connection to said tissue and means responsive to externally generated signals for programming said alterable output parameter in predetermined correspondence with said signals, the improvement wherein said programming means comprises:

means for detecting first externally generated signals of predetermined characteristics;

means responsive to detected first signals for altering said alterable output parameter in predetermined correspondence with said first signals;

means for detecting second externally generated signals of predetermined characteristics discriminable from the characteristics of said first signals; and

means responsive to detected second signals for enabling said output parameter altering means only during the occurrence of said second signals.

2. The device of claim 1 wherein said enabling means enables said output parameter altering means a predetermined time following the initiation of one of said second signals.

3. The device of claim 1 wherein said output parameter altering means comprises means for generating a control signal on the occurrence of each of said first signals and means responsive to said control signals for altering said output parameter in predetermined correspondence with the number of said control signals, said enabling means comprising means for allowing the generation of a control signal only during the occurrence of said second signals.

4. The device of claim 3 wherein said enabling means further comprises means for preventing the generation of a control signal for a predetermined time following the intitiation of one of said second signals.

5. The device of claim 3 wherein said control signal responsive means includes counter means having a plurality of sequential states for advancing its state in response to each control signal and further comprising means for resetting said counter means to a preselected state in response to the first control signal following the initiation of one of said second signals.

6. The device of claim 5 wherein said enabling means further comprises means for preventing the generation of a control signal for a predetermined time following the initiation of one of said second signals.

7. The device of claim 6 wherein said resetting means resets said counter means to said preselected state after said counter has advanced its state in response to the first control signal following the initiation of one of said second signals.

8. The device of claim 6 wherein said enabling means comprises means for enabling said counter means only during the occurrence of said second signals.

9. The device of claim 1 wherein said output parameter altering means includes counter means having a plurality of sequential states for advancing its state in response to said first signals, said enabling means comprising means for enabling said counter means only during the occurrence of said second signals.

10. The device of claim 1 wherein said first signals are pulsed r f signals and said second signals are magnetic.

11. The device of claim 1 wherein said device comprises a cardiac pacemaker, said output means being adapted for connection to the heart.

12. The device of claim 11 further comprising means adapted for connection to the heart to sense heart activity including means for inhibiting said pulse generator when the sensed activity satisfies certain preselected parameters, said enabling means including means for disabling said inhibiting means during the occurrence of said second signals.

13. The device of claim 12 wherein said enabling means enables said output parameter altering means a predetermined time following the initiation of one of said second signals.

14. The device of claim 12 wherein said output parameter altering means comprises means for generating a control signal on the occurrance of each of said first signals and means responsive to said control signals for altering said output parameter in predetermined correspondence with the number of said control signals, said enabling means comprising means for allowing the generation of a control signal only during the occurrence of said second signals.

15. The device of claim 14 wherein said enabling means further comprises means for preventing the generation of a control signal for a predetermined time following the initiation of one of said second signals.

16. The device of claim 14 wherein said control signal responsive means includes counter means having a plurality of sequential states for advancing its state in response to each control signal and further comprising means for resetting said counter means to a preselected state in response to the first control signal following the initiation of one of said second signals.

17. The device of claim 16 wherein said enabling means further comprises means for preventing the generation of a control signal for a predetermined time following the initiation of one of said second signals.

18. The device of claim 17 wherein said resetting means resets said counter means to said preselected state after said counter means has advanced its state in response to the first control signal following the initiation of one of said second signals.

19. The device of claim 17 wherein said enabling means comprises means for enabling said counter means only during the occurrence of said second signals.

20. The device of claim 12 wherein said output parameter altering means includes counter means having a plurality of sequential states for advancing its state in response to said first signals, said enabling means comprising means for enabling said counter means only during the occurrence of said second signals.

21. The device of claim 12 wherein said first signals are pulsed r f signals and said second signals are magnetic.

22. The device of claim 11 wherein said first signals are pulsed r f signals and said second signals are magnetic.

23. In a body-implantable device for providing electrical stimulation to living animal tissue of the type having pulse generator means with at least one alterable output parameter, output means adapted for connection to said tissue and means responsive to externally generated signals for programming said output parameter in predetermined correspondence with said signals, the improvement wherein said programming means comprises:

means for detecting first externally generated signals of predetermined characteristics;

means responsive to detected first signals for generating a sequence of control signals, one control signal on the occurrence of each of said first signals;

counter means having a plurality of sequential states and connected to receive said control signals for advancing its state in response to each control signal;

means responsive to said control signals for resetting said counter means in response to the first control signal in a sequence of control signals;

means for detecting second externally generated signals of predetermined characteristics discriminable from the characteristics of said first signals; and

means responsive to detected second signals for enabling said control signal generating means only during the occurrence of said second signals.

24. The device of claim 23 wherein said control signal generating means comprises means responsive to transmitted pulses of radio frequency energy and means for demodulating said radio frequency energy pulses.

25. The device of claim 24 wherein said enabling means comprises magnetically operable switch means for selectively enabling said demodulating means.

26. The device of claim 25 further comprising means interconnecting said magnetically operable switch means and said demodulating means for delaying the enabling of said demodulating means by a predetermined time interval.

27. The device of claim 26 wherein said delaying means comprises:

transistor switch means interconnecting said magnetically operable switch means and said demodulating means and responsive to said magnetically operable switch means for enabling said demodulating means; and

circuit means for delaying the enabling response of said transistor switch means to said magnetically operable switch means for a predetermined time interval.

28. The device of claim 27 further comprising means interconnecting said counter means and said magnetically operable switch means and responsive to said magnetically operable switch means for selectively enabling said counter means.

29. The device of claim 28 wherein said resetting means comprises energy storage means and means enabled by said enabling means for charging said energy storage means on the occurrence of each control signal.