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

• US 7,725,186 B1
• Filed: 11/30/2006
• Issued: 05/25/2010
• 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): Layno; Carl H
• Assistant Examiner(s): PATEL, NATASHA
• Application Number:
  US11/565,348
• Time in Patent Office: 1,272 Days
• Field of Search: 600/506, 600/513, 600/547, 600/587, 600/595, 600/301, 600/323, 600/483, 607/17, 607/18, 607/22
• US Class Current: 607/18
• 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) using a first sensor to monitor a patient'"'"'s oxygen saturation level, wherein said first sensor requires a first external excitation current to monitor oxygen saturation level; and

(b) triggering use of a multi-dimensional activity sensor for a pre-defined period of time when the monitored oxygen saturation level drops below a specified level,

wherein the multi-dimensional activity sensor monitors at least two dimensions of activity that are useful for monitoring disease progression, and

wherein the multi-dimensional activity sensor requires a second excitation current to produce one or more signal indicative of the at least two dimensions of activity, the second excitation current being greater than the first external excitation current.

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 multi-dimensional activity sensor.

3. The method of claim 2, further comprising:

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

4. The method of claim 3, further comprising:

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

5. The method of claim 1, wherein the multi-dimensional activity sensor monitors at least two dimensions of activity indicative of two or more of acceleration, direction, posture and tilt.

6. The method of claim 5, wherein in step (b) the period of time, for which use of the multi-dimensional activity sensor is triggered, is approximately only long enough such that the one or more signal produced by the multi-dimensional activity sensor includes enough information to determine the at least two dimensions of activity.

7. The method of claim 1, wherein in step (b) the period of time, for which use of the multi-dimensional activity sensor is triggered, is approximately only long enough such that the one or more signal produced by the multi-dimensional activity sensor includes enough information to determine the at least two dimensions of activity.

8. An implantable cardiac stimulation device, comprising:

a first sensor that monitors a patient'"'"'s oxygen saturation level, wherein said first sensor requires a first external excitation current to monitor oxygen saturation level; and

a multi-dimensional activity sensor that monitors at least two dimensions of activity that are useful for monitoring disease progression,

wherein the multi-dimensional activity sensor requires a second excitation current to produce one or more signal indicative of the at least two dimensions of activity, the second excitation current being greater than the first external excitation current; and

wherein temporary use of the multi-dimensional activity sensor for a pre-defined period of time is triggered when the monitored oxygen saturation level drops below a specified level.

9. The device of claim 8, further comprising:

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

10. The device of claim 9, further comprising:

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

11. The device of claim 10, further comprising:

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

12. The device of claim 8, wherein the multi-dimensional activity sensor monitors at least two dimensions of activity indicative of two or more of acceleration, direction, posture and tilt.

13. The device of claim 12, wherein the period of time, for which temporary use of the multi-dimensional activity sensor is triggered, is approximately only long enough such that the one or more signal produced by the multi-dimensional activity sensor includes enough information to determine the at least two dimensions of activity.

14. The device of claim 8, wherein the period of time, for which temporary use of the multi-dimensional activity sensor is triggered, is approximately only long enough such that the one or more signal produced by the multi-dimensional activity sensor includes enough information to determine the at least two dimensions of activity.

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

(a) using a first sensor to monitor a patient'"'"'s oxygen saturation level, wherein said first sensor requires a first external excitation current to monitor oxygen saturation level; and

(b) in response to the monitored oxygen saturation level dropping below a specified oxygen saturation threshold, triggering use of a multi-dimensional activity sensor for a period of time that is approximately only long enough to obtain a threshold amount of information indicative of a specified at least two dimensions of activity;

wherein the multi-dimensional activity sensor requires a second excitation current to obtain the information indicative of the specified at least two dimensions of activity, the second excitation current being greater than the first external excitation current.

16. The method of claim 15, further comprising:

(c) storing the obtained information indicative of the specified at least two dimensions of activity.

17. The method of claim 16, further comprising:

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

18. The method of claim 17, further comprising:

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

19. The method of claim 15, wherein the specified at least two dimensions of activity include two or more of acceleration, direction, posture and tilt.