Complimentary activity sensor network for disease monitoring and therapy modulation in an implantable device

• US 7,155,281 B1
• Filed: 12/03/2004
• Issued: 12/26/2006
• Est. Priority Date: 12/03/2004
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Fayram, Timothy A.
• Primary Examiner(s): Pezzuto, Robert E.
• Assistant Examiner(s): Patel, Natasha
• Application Number:
  US11/003,203
• Time in Patent Office: 753 Days
• Field of Search: 607/6, 607/16, 607/17, 607/18, 607/19, 607/62, 600/506, 600/513, 600/547, 600/587, 600/595, 600/301, 600/323, 600/483
• US Class Current: 607/19
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/1123 Discriminating type of movement, e.g. walking or running A61B5/1116, A61B5/112 take precedence
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters

Abstract

Energy efficient methods and systems for using multi-dimensional activity sensors with implantable cardiac devices are provided. In certain embodiments the output of a passive activity sensor (used for rate responsive pacing) is used to trigger temporary use of a relatively high power multi-dimensional activity sensor. In other embodiments, the output of a relatively low power oxygen saturation sensor is used to trigger temporary use of a relatively high power multi-dimensional activity sensor. This description is not intended to be a complete description of, or limit the scope of, the invention.

Claims

1. A method for use with an implantable cardiac stimulation device, the method comprising:

(a) continually using a passive activity sensor to produce a signal indicative of acceleration is used for rate responsive pacing, wherein the passive activity sensor does not require an external excitation current for it to produce its signal; and

(b) intermittently using an active activity sensor to monitor at least two dimensions of activity indicative of two or more of acceleration, direction, posture, and tilt, wherein monitoring of the at least two dimensions are useful for monitoring disease progression, wherein the active activity sensor requires an external excitation current to produce one or more signal indicative of the at least two dimensions of activity.

2. The method of claim 1, further comprising:

(c) storing data and timing information indicative of the at least two dimensions of activity monitored using the active activity sensor.

3. The method of claim 2, further comprising:

(d) analyzing the stored data and timing information to thereby quantify a patient'"'"'s activity level over a specified period of time.

4. The method of claim 3, further comprising:

(e) triggering an alert in response to a determination that the patient'"'"'s activity level over the specified period of time drops below a specified level.

5. The method of claim 4, wherein step (b) includes triggering temporary use of the active activity sensor when at least a predetermined amount of activity is sensed using the passive activity sensor.

6. The method of claim 1, wherein step (b) includes triggering temporary use of the active activity sensor when at least a predetermined amount of activity is sensed using the passive activity sensor.

7. The method of claim 6, further comprising:

(c) storing data and timing information indicative of the at least two dimensions of activity monitored by the active activity sensor.

8. The method of claim 7, further comprising:

(d) analyzing the stored data and timing information to thereby determine whether a patient'"'"'s activity level over a specified period of time drops below a specified level.

9. The method of claim 8, further comprising:

(e) triggering an alert in response to a determination that the patient'"'"'s activity level over a specified period of time drops below the specified level.

10. The method of claim 1, wherein the active activity sensor requires an excitation current of at least 0.7 mA to produce its said one or more signal.

11. The method of claim 10, wherein a parasitic current required to measure the signal produced by the passive activity sensor is less than 1 μ

A.

12. The method of claim 1, wherein step (b) includes using the active activity sensor in accordance with a duty cycle that is less than 50%.

13. The method of claim 1, wherein step (b) includes using the active activity sensor in accordance with a duty cycle that is less than 25%.

14. The method of claim 1, wherein the passive activity sensor comprises a piezoelectric device.

15. An implantable cardiac stimulation device, comprising:

a passive activity sensor that continually produces a signal indicative of acceleration is used for rate responsive pacing, wherein the passive activity sensor does not require an external excitation current for it to produce its signal; and

an active activity sensor indicative of two or more of acceleration, direction, posture, and tilt, wherein monitoring of the at least two dimensions intermittently monitors at least two dimensions of activity that are useful for monitoring disease progression, wherein the active activity sensor requires an external excitation current to produce one or more signal indicative of the at least two dimensions of activity.

16. The device of claim 15, further comprising:

means for storing data and timing information indicative of the at least two dimensions of activity monitored using the active activity sensor.

17. The device of claim 16, further comprising:

means for analyzing the stored data and timing information to thereby quantify a patient'"'"'s activity level over a specified period of time.

18. The device of claim 17, further comprising:

an alert that is triggered in response to a determination that the patient'"'"'s activity level over the specified period of time drops below a specified level.

19. The device of claim 18, wherein temporary use of the active activity sensor is triggered when at least a predetermined amount of activity is sensed using the passive activity sensor.

20. The device of claim 15, wherein temporary use of the active activity sensor is triggered when at least a predetermined amount of activity is sensed using the passive activity sensor.

21. The device of claim 20, further comprising:

means for storing data and timing information indicative of the at least two dimensions of activity monitored by the active activity sensor.

22. The device of claim 21, further comprising:

means for analyzing the stored data and timing information to thereby determine whether a patient'"'"'s activity level over a specified period of time drops below a specified level.

23. The device of claim 22, further comprising:

an alert that is triggered in response to a determination that the patient'"'"'s activity level over a specified period of time drops below the specified level.

24. The device of claim 15, wherein the active activity sensor requires an excitation current of at least 0.7 mA to produce its said one or more signal.

25. The device of claim 24, wherein a parasitic current required to measure the signal produced by the passive activity sensor is less than 1 μ

A.

26. The device of claim 15, wherein the active activity sensor is used in accordance with a duty cycle that is less than 50%.

27. The device of claim 15, wherein the active activity sensor is used in accordance with a duty cycle that is less than 25%.

28. The device of claim 15, wherein the passive activity sensor comprises a piezoelectric device.