Subcutaneous multi-electrode sensing system, method and pacer

• US 5,331,966 A
• Filed: 12/16/1993
• Issued: 07/26/1994
• Est. Priority Date: 04/05/1991
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Combs, William J., Lee, Brian B., Mehra, Rahul, Klein, George J., Kallok, Michael J., Bennett, Tom D.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US08/168,725
• Time in Patent Office: 222 Days
• Field of Search: 128/642, 128/696, 128/697, 128/903, 607/9, 607/28
• US Class Current: 600/508
• CPC Class Codes: A61N 1/0504 Subcutaneous electrodes
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3686 configured for selecting the electrode configuration on a lead A61N1/3688 takes precedence
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

A method and apparatus for providing an enhanced capability of detecting and gathering electrical cardiac signals via an array of relatively closely spaced subcutaneous electrodes (located on the body of an implanted device) which may be employed with suitable switching circuits, signal processors, and memory to process the electrical cardiac signals between any selected pair or pairs of the electrode array in order to provide a leadless, orientation insensitive means for receiving the electrical signal from the heart. This far-field EGM may be used to provide storage and analysis of arrhythmic events and to provide control signals for the delivery of various therapies including pacing, cardioversion and defibrillation therapies as well as the delivery of antiarrhythmic drugs, and, in the pacing context, to effect capture detection and automatic stimulation threshold adaption, recording of PMT episodes, measurement of refractory periods in order to set timing windows for antitachy pacing therapies, and as a control signal for use in adjusting pacing rate to physiologic demand.

Claims

1. An apparatus for monitoring cardiac signals, comprising:

a hermetically sealed housing;

first and second pairs of electrodes mounted to said housing;

sensing means, located within said housing, for sensing cardiac signals;

command means, located outside said housing, for providing command signals indicative of which of said first and second electrode pairs are to be coupled to said sensing means;

selecting means, located within said housing and responsive to said command signals, for selectively coupling said first and second electrode pairs to said sensing means;

processing means, located within said housing, for processing and converting said sensed cardiac signals into data signals; and

means for storing said data signals.

4. An apparatus according to claim 1 or claim 2 or claim 3 further comprising:

means for generating a store command; and

means responsive to said store command for storing said sensed cardiac signals.

5. An apparatus according to claim 4 wherein said store command generating means comprises means responsive to said sensed cardiac signals, for generating said store command in response to the occurrence of sensed cardiac signals.

6. An apparatus according to claim 4 wherein said store command generating means comprises a transmitter means external to said housing, for transmitting said store command to said responsive means.

15. An apparatus according to claim 1 or claim 2 or claim 3 or claim 7 or claim 8 or claim 9 or claim 10 or claim 11 or claim 12, wherein at least one of said first and second electrode pairs comprises an electrode means adjacent to said housing, for location in subcutaneous tissue, mounted to said housing by means of an electrical lead extending from said housing.

16. A pacemaker according to claim 15 wherein said responsive means comprises means for defining a preferred cardiac signal and means for determining which of said first and second electrode paris provides said preferred cardiac signal and selecting means responsive to said determining means for selectively coupling one of said first and second electrode pairs of said sensing means for subsequent use in detecting capture of said patient'"'"'s heart.

2. An apparatus for monitoring cardiac signals, comprising:

a hermetically sealed housing;

first and second pairs of electrodes mounted to said housing;

sensing means, located within said housing, for sensing cardiac signals;

command means, located outside said housing, for providing command signals indicative of which of said first and second electrode pairs are to be coupled to said sensing means;

selecting means, located within said housing and responsive to said command signals, for selectively coupling said first and second electrode pairs to said sensing means;

means for defining operational parameters of said apparatus;

means for processing and converting said sensed cardiac signals into a control signal; and

means responsive to said control signal for altering a said operational parameter of said apparatus.

3. An apparatus for monitoring cardiac signals, comprising:

a hermetically sealed housing;

first and second pairs of electrodes mounted to said housing;

sensing means, located within said housing, for sensing cardiac signals;

command means, located outside said housing, for providing command signals indicative of which of said first and second electrode pairs are to be coupled to said sensing means;

selecting means, located within said housing and responsive to said command signals, for selectively coupling said first and second electrode pairs to said sensing means; and

transmitter means for transmitting said sensed cardiac signals from said housing.

7. An apparatus for monitoring cardiac signals, comprising:

a hermetically sealed housing;

first and second pairs of electrodes mounted to said housing;

sensing means, located within said housing, for sensing cardiac signals and for generating output signals corresponding to said sensed cardiac signals;

selecting means, located within said housing, for selectively coupling said first and second electrode pairs to said sensing means;

means for defining a preferred cardiac signal;

means for comparing said output signals generated when said sensing means is coupled to said first electrode pair to said output signals generated when said sensing means is coupled to said second electrode pair to determine which of said first and second electrode pairs produces said preferred cardiac signal;

control means, responsive to said comparing means, for controlling said selecting means to couple said sensing means to the one of said first and second electrode pairs which produces said preferred cardiac signal;

processing means, located within said housing, for processing and converting said output signals into data signals; and

means for storing said data signals.

8. An apparatus for monitoring cardiac signals, comprising:

a hermetically sealed housing;

first and second pairs of electrodes mounted to said housing;

sensing means, located within said housing, for sensing cardiac signals and for generating output signals corresponding to said sensed cardiac signals;

selecting means, located within said housing, for selectively coupling said first and second electrode pairs to said sensing means;

means for defining a preferred cardiac signal;

means for comparing said output signals generated when said sensing means is coupled to said first electrode pair to said output signals generated when said sensing means is coupled to said second electrode pair to determine which of said first and second electrode pairs produces said preferred cardiac signal; and

control means, responsive to said comparing means, for controlling said selecting means to couple said sensing means to the one of said first and second electrode pairs which produces said preferred cardiac signal

means for defining operational parameters of said apparatus;

means for processing and converting said output signals into a control signal; and

means responsive to said control signal for altering a said operational parameter of said apparatus.

9. An apparatus for monitoring cardiac signals, comprising:

a hermetically sealed housing;

first and second pairs of electrodes mounted to said housing;

sensing means, located within said housing, for sensing cardiac signals and for generating output signals corresponding to said sensed cardiac signals;

selecting means, located within said housing, for selectively coupling said first and second electrode pairs to said sensing means;

means for defining a preferred cardiac signal;

means for comparing said output signals generated when said sensing means is coupled to said first electrode pair to said output signals generated when said sensing means is coupled to said second electrode pair to determine which of said first and second electrode pairs produces said preferred cardiac signal;

control means, responsive to said comparing means, for controlling said selecting means to couple said sensing means to the one of said first and second electrode pairs which produces said preferred cardiac signal; and

transmitter means for transmitting said output signals from said housing.

10. An apparatus for monitoring cardiac signals, comprising:

a hermetically sealed housing;

first and second electrode pairs mounted to said housing;

sensing means coupled to said first and second electrode pairs for sensing cardiac signals from said first and second electrode pairs and for generating first and second output signals corresponding to cardiac signals sensed from said first and second electrode pairs, respectively; and

signal processing means coupled to said sensing means for combining said first and second output signals to provide combined output signals; and

means for storing said combined output signals.

13. An apparatus according to claim 10 or claim 11 or claim 12 wherein said combining means comprises means for combining said first and second output signals to derive directional vectors and means for providing combined output signals which comprise magnitudes of said directional vectors.

14. An apparatus according to claim 10 or claim 11 or claim 12 wherein said combining means comprises means for combining said first and second output signals to derive directional vectors and means for providing combined output signals which comprise magnitudes and directions of said directional vectors.

11. An apparatus for monitoring heart signals, comprising:

a hermetically sealed housing;

first and second electrode pairs mounted to said housing;

sensing means coupled to said first and second electrode pairs for sensing cardiac signals from said first and second electrode pairs and for generating first and second output signals corresponding to cardiac signals sensed from said first and second electrode pairs, respectively; and

signal processing means coupled to said sensing means for combining said first and second output signals to provide combined output signals;

means for defining operational parameters of said apparatus;

means for processing and converting said combined output signals into a control signal; and

means responsive to said control signal for altering a said operational parameter of said apparatus.

12. An apparatus for monitoring cardiac signals, comprising;

a hermetically sealed housing;

first and second electrode pairs mounted to said housing;

sensing means coupled to said first and second electrode pairs for sensing cardiac signals from said first and second electrode pairs and for generating first and second output signals corresponding to cardiac signals sensed from said first and second electrode pairs, respectively; and

signal processing means coupled to said sensing means for combining said first and second output signals to provide combined output signals; and

transmitter means for transmitting said combined output signals from said housing.

17. A method of monitoring cardiac signals, comprising:

implanting in a patient an apparatus comprising a hermetically sealed housing, first and second pairs of electrodes mounted to said housing, a sensing means located within said housing for sensing cardiac signals and selecting means located within said housing and responsive to command signals for selectively coupling said first and second electrode pairs to said sensing means, such that said housing and said first and second electrode pairs are located outside of said patient'"'"'s heart in the subcutaneous tissue of said patient;

transmitting a said command signal indicative of which of said first and second electrode pairs are to be coupled to said sensing means to said apparatus from outside of said housing; and

subsequently employing said coupled electrode pair to monitor said cardiac signals.

18. A method according to claim 17 further comprising:

processing and converting said sensed cardiac signals into data signals; and

storing said data signals.

19. A method according to claim 18 further comprising transmitting said sensed cardiac signals from said housing.

20. A method according to claim 17, further comprising:

defining operational parameters for said apparatus;

processing and converting said sensed cardiac signals into a control signal; and

employing said control signal to alter a said operational parameter of said apparatus.

28. A method according to claim 17 or claim 21 or claim 25, wherein said step of implanting said apparatus comprises implanting at least one of said first and second electrode pairs having an electrode located adjacent to said housing, in said subcutaneous tissue, mounted to said housing by means of an electrical lead extending from said housing.

21. A method of monitoring cardiac signals, comprising:

defining a preferred cardiac signal;

implanting in a patient a device comprising a hermetically sealed housing, first and second pairs of electrodes mounted to said housing, a sensing means located within said housing for sensing cardiac signals and for generating output signals corresponding to said sensed cardiac signals and selecting means located within said housing for selectively coupling said first and second electrode pairs to said sensing means;

such that said housing and said first and second electrode pairs are located outside of said patient'"'"'s heart in subcutaneous tissue of said patient;

selectively coupling said sensing means to said first and second electrode pairs;

comparing said output signals generated when said sensing means is coupled to said first electrode pair to said output signals generated when said sensing means is coupled to said second electrode pair to determine which of said first and second electrode pairs produces said preferred cardiac signal;

employing said selecting means to couple said sensing means to the one of said first and second electrode pairs which produces said preferred cardiac signal; and

subsequently employing said one of said first and second electrode pairs which produces said preferred cardiac signal to monitor said cardiac signals.

22. A method according to claim 21 further comprising:

processing and converting said sensed cardiac signals into data signals; and

storing said data signals.

23. A method according to claim 21, further comprising:

defining operational parameters for said apparatus;

processing and converting said sensed cardiac signals into a control signal; and

employing said control signal to alter a said operational parameter of said apparatus.

24. A method according to claim 21 further comprising transmitting said sensed cardiac signals from said housing.

25. A method of monitoring cardiac signals, comprising:

implanting in a patient an apparatus comprising a hermetically sealed housing, first and second electrode pairs mounted to said housing and sensing means located within said housing coupled to said first and second electrode pairs for sensing cardiac signals from said first and second electrode pairs and for generating first and second output signals corresponding to cardiac signals sensed from said first and second electrode pairs, respectively, such that said housing and said first and second electrode pairs are located outside of said patient'"'"'s heart in subcutaneous tissue of said patient;

combining said first and second output signals to provide combined output signals; and

employing said combined output signals to monitor the heart activity of said patient.

26. A method according to claim 25 wherein said combining step comprises combining said first and second output signals to derive directional vectors and providing combined output signals which comprise magnitudes of said directional vectors.

27. A method according to claim 25 wherein said combining step comprises combining said first and second output signals to derive directional vectors and providing combined output signals which comprise magnitudes and directions of said directional vectors.

29. In an implantable cardiac pacemaker having pulse generator means for providing pacing pulses to cardiac tissue, output energy setting means for setting the energy of the applied pacing pulses and apparatus for detecting capture of a patient'"'"'s heart by the applied pacing pulses, said capture detecting apparatus comprising means for sensing cardiac signals closely following said applied pacing pulses, the improvement wherein:

said apparatus for detecting capture of the patient'"'"'s heart comprises first and second electrode pairs, sensing means coupled to said first and second pairs of electrodes for sensing cardiac signals applied thereto and means responsive to said sensed cardiac signals from both said first and second electrode pairs for detecting capture of said patient'"'"'s heart.