Subcutaneous cardiac stimulation system with patient activity sensing

• US 20040220633A1
• Filed: 04/01/2004
• Published: 11/04/2004
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Haefner, Paul, Wagner, Darrell Orvin
• Granted Patent: US 7,117,035 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61B 17/3203 Fluid jet cutting instruments
• CPC Class Codes: A61B 17/3415 for introducing tubes or catheters, e.g. gastrostomy tubes, drain catheters A61B17/3417 takes precedence; body piercing catheter guide needles A61M25/06
• CPC Class Codes: A61B 17/3417 Details of tips or shafts, e.g. grooves, expandable, bendable; Multiple coaxial sliding cannulas, e.g. for dilating syringe needles A61M5/32; dilators A61M29/00
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2017/00247 Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• CPC Class Codes: A61B 2017/320044 Blunt dissectors blunt suture needles A61B2017/06085
• CPC Class Codes: A61B 2017/320084 Irrigation sleeves
• CPC Class Codes: A61B 2018/00392 Transmyocardial revascularisation
• CPC Class Codes: A61B 2090/3945 Active visible markers, e.g. light emitting diodes
• CPC Class Codes: A61B 2217/005 with suction drainage system
• CPC Class Codes: A61B 2217/007 with irrigation system
• CPC Class Codes: A61B 90/30 Devices for illuminating a surgical field, the devices having an interrelation with other surgical devices or with a surgical procedure
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/0568 with drug delivery
• CPC Class Codes: A61N 1/0587 Epicardial electrode systems; Endocardial electrodes piercing the pericardium
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

A system includes a housing with energy delivery circuitry and detection circuitry. One or more electrodes are coupled to the circuitry and used to sense cardiac and muscle activity. A processor is coupled to the energy delivery and detection circuitry. The processor may detect a ventricular arrhythmia using a cardiac signal developed from the sensed cardiac activity and may also detect an activity state of the patient using an activity signal developed from the sensed muscle activity. The processor modifies delivery of a therapy to treat the arrhythmia in response to the activity signal. A method involves detecting signals using subcutaneous electrodes, and discerning a cardiac signal and a patient activity signal from the detected signals. Arrhythmia therapy may be modified to treat the arrhythmia in response to the activity signal.

Claims

1. An implantable cardiac stimulation device, comprising:

a housing configured for subcutaneous non-intrathoracic placement in a patient;

energy delivery circuitry provided in the housing;

detection circuitry provided in the housing;

one or more electrodes coupled to the energy delivery and detection circuitry and configured for subcutaneous non-intrathoracic placement in a patient, the one or more electrodes sensitive to cardiac and muscle activity; and

a processor provided in the housing and coupled to the energy delivery and detection circuitry, the processor detecting a arrhythmia using a cardiac signal developed from the sensed cardiac activity and detecting an activity state of the patient using an activity signal developed from the sensed muscle activity, the processor modifying delivery of a therapy that treats the arrhythmia in response to the activity signal.

2. The device of claim 1, wherein the processor inhibits delivery of the arrhythmia therapy in response to the activity signal exceeding an activity threshold.

3. The device of claim 1, wherein the processor inhibits delivery of the arrhythmia therapy in response to the activity signal indicating patient consciousness or movement.

4. The device of claim 1, wherein the processor inhibits delivery of the arrhythmia therapy for a predetermined time period in response to the activity signal exceeding an activity threshold, and withholds delivery of the arrhythmia therapy upon expiration of the predetermined time period and cessation of the arrhythmia.

5. The device of claim 1, wherein the processor inhibits delivery of the arrhythmia therapy for a predetermined time period in response to the activity signal exceeding an activity threshold, and delivers the arrhythmia therapy upon expiration of the predetermined time period and non-cessation of the arrhythmia.

6. The device of claim 1, wherein the processor inhibits delivery of the arrhythmia therapy in response to the activity signal exceeding an activity threshold, and wherein the processor provides a notification that the arrhythmia therapy is inhibited.

7. The device of claim 1, wherein:

in response to the activity signal indicating patient consciousness or movement, the processor inhibits delivery of the arrhythmia therapy; and

in response to detection of a life-threatening arrhythmia, the processor immediately delivers the arrhythmia therapy irrespective of the activity signal.

8. The device of claim 1, wherein the processor receives an electrocardiogram using the detection circuitry and discriminates the cardiac signal and the activity signal from the electrocardiogram.

9. The device of claim 8, wherein the processor discriminates the cardiac and activity signals using a signal separation technique.

10. The device of claim 8, wherein the processor discriminates the cardiac and activity signals using blind source separation.

11. The device of claim 8, wherein the one or more electrodes comprises:

a first combination of electrodes adapted to preferentially sense cardiac signals associated with the cardiac activity; and

a second combination of electrodes adapted to preferentially sense noise signals associated with the muscle activity.

12. The device of claim 11, wherein:

the one or more electrodes comprises a plurality of electrodes;

the processor selects combinations of the plurality of electrodes; and

the processor senses a cardiac signal component and a noise component of signals acquired by each of the controller selected electrode combinations.

13. The device of claim 1, wherein the processor detects the arrhythmia using morphology based arrhythmia detection.

14. The device of claim 1, wherein the processor detects the arrhythmia using rate based arrhythmia detection.

15. The device of claim 1, wherein the one or more electrodes comprise a plurality of electrodes, and wherein the processor detects the arrhythmia using an activation sequence over the plurality of electrodes.

16. The device of claim 1, wherein the processor detects the arrhythmia using a cardiac signal curvature.

17. A cardiac stimulation method, comprising:

detecting signals at one or more subcutaneous non-intrathoracic locations;

discerning a cardiac signal from the detected signals;

discerning an activity signal associated with muscle activity from the detected signals;

detecting a arrhythmia using the cardiac signal;

detecting a patient activity state using the activity signal; and

modifying delivery of a subcutaneous non-intrathoracic therapy that treats the arrhythmia in response to the activity signal.

18. The method of claim 17, wherein delivery of the arrhythmia therapy is inhibited in response to the activity signal exceeding an activity threshold.

19. The method of claim 17, wherein delivery of the arrhythmia therapy is inhibited in response to the activity signal indicating patient consciousness or movement.

20. The method of claim 17, wherein delivery of the arrhythmia therapy is inhibited for a predetermined time period in response to the activity signal exceeding an activity threshold, and delivery of the arrhythmia therapy is withheld upon expiration of the predetermined time period and cessation of the arrhythmia.

21. The method of claim 17, wherein delivery of the arrhythmia therapy is inhibited for a predetermined time period in response to the activity signal exceeding an activity threshold, and the arrhythmia therapy is delivered upon expiration of the predetermined time period and non-cessation of the arrhythmia.

22. The method of claim 17, wherein:

in response to the activity signal indicating patient consciousness or movement, inhibiting delivery of the arrhythmia therapy; and

in response to detection of a life-threatening arrhythmia, immediately delivering the arrhythmia therapy irrespective of the activity signal.

23. The device of claim 17, wherein discerning the cardiac and activity signals comprises discriminating the cardiac and activity signals using a signal separation technique on the detected signals.

24. The method of claim 17, wherein discerning the cardiac and activity signals comprises performing a blind source separation on the detected signals.

25. The method of claim 17, wherein detecting the signals comprises detecting the signals using a plurality of electrodes provided at a plurality of non-intrathoracic locations, the electrodes selectively combinable to define a plurality of sensing vectors, and discerning the cardiac and activity signals comprises:

selecting a first sensing vector of the plurality of sensing vectors which is preferentially sensitive to signals associated with cardiac activity; and

selecting a second sensing vector of the plurality of sensing vectors which is preferentially sensitive to signals associated with the muscle activity.

26. The method of claim 17, wherein the muscle activity is indicative of patient movement, and discerning the activity signal comprises detecting an accelerometer signal indicative of the patient movement.

27. The method of claim 17, wherein the arrhythmia is detected using morphology based arrhythmia detection.

28. The method of claim 17, wherein the arrhythmia is detected using rate based arrhythmia detection.

29. The method of claim 17, wherein the arrhythmia is detected using an activation sequence detected by a plurality of electrodes.

30. The method of claim 17, wherein the arrhythmia is detected using a curvature of the cardiac signal.

31. A cardiac stimulation device, comprising:

means for detecting signals at one or more subcutaneous non-intrathoracic locations;

means for discerning a cardiac signal and a muscle activity signal from the detected signals;

means for detecting a arrhythmia using the cardiac signal;

means for detecting a patient activity state using the activity signal; and

means for modifying delivery of a subcutaneous non-intrathoracic therapy that treats the arrhythmia in response to the activity signal.

32. The device of claim 31, wherein the delivery modifying means comprises means for inhibiting arrhythmia therapy delivery in response to the activity signal.

33. The device of claim 32, wherein the delivery modifying means comprises means for immediately delivering the arrhythmia therapy in response to detecting a life-threatening arrhythmia irrespective of the activity signal.

34. The device of claim 31, wherein the discerning means comprises means for separating the cardiac and activity signals respectively from the detected signals.

35. The device of claim 31, wherein the discerning means comprises means for acquiring an accelerometer signal indicative of patient movement.