METHOD AND APPARATUS FOR DETECTING ARRHYTHMIAS IN A MEDICAL DEVICE

• US 20080275519A1
• Filed: 05/01/2007
• Published: 11/06/2008
• Est. Priority Date: 05/01/2007
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Kleckner, Karen J., Krause, Paul G., Ghanem, Raja N., Stadler, Robert W., Zhang, Xusheng
• Granted Patent: US 8,095,206 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting

Abstract

A method and apparatus for adjusting a sensing parameter in a medical device that includes a sensing electrode sensing cardiac signals, a processor to determine an adjusting characteristic associated with the cardiac signals sensed over a predetermined sensing window, and a control unit to update the sensing parameter in response to the determined adjusting characteristic.

Claims

1. An apparatus for adjusting a sensing parameter in a medical device, comprising:

a sensing electrode sensing cardiac signals;

a processor to determine an adjusting characteristic associated with the cardiac signals sensed over a predetermined sensing window; and

a control unit to update the sensing parameter in response to the determined adjusting characteristic.

2. The apparatus of claim 1, wherein the processor defines a plurality of sub-segments associated with the sensing window, and determines the adjusting characteristic associated with the cardiac signals within each sub-segment of the plurality of sub-segments.

3. The apparatus of claim 1, wherein the cardiac signals are sensed non-transvenously.

9. The apparatus of claim 1, wherein the processor defines a plurality of sub-segments associated with the sensing window, determines intervals associated with each sub-segment of the plurality of sub-segments, and determines a rate associated with each sub-segment of the plurality of sub-segments in response to the determined intervals, and wherein the control unit adjusts the sensing parameter in response to the determined rate associated with each sub-segment of the plurality of sub-segments.

10. The apparatus of claim 9, wherein the processor determines the number of sub-segments of the plurality of sub-segments for which the sub-segment rate was determined, and wherein the control unit varies the adjusting of the sensing parameter in response to the determined number of sub-segments.

4. The apparatus of 2, wherein the processor determines a sub-segment parameter for each of the plurality of sub-segments, compares the sub-segment parameter with a sub-segment parameter threshold, and wherein the control unit determines whether to update the sensing parameter in response to the comparing.

5. The apparatus of claim 4, wherein the processor determines a sensing window parameter associated with the sensing window, and sets the sub-segment parameter threshold equal to the determined sensing window parameter.

6. The apparatus of claim 4, wherein the processor determines a maximum amplitude and an absolute minimum amplitude associated with the sensing window, compares the maximum amplitude and the absolute minimum amplitude, and determines the sub-segment parameter and the sub-segment parameter threshold in response to the comparing of the maximum amplitude and the absolute minimum amplitude.

7. The apparatus of claim 4, wherein the processor determines a local parameter for each sub-segment of the plurality of sub-segments, and compares the local parameter with the sub-segment parameter.

8. The apparatus of claim 7, wherein the control unit updates the sensing parameter only in response to the sub-segment parameter and one or more local parameters being determined for a predetermined number of sub-segments of the plurality of sub-segments.

11. A method of updating a sensing parameter in a medical device, comprising:

sensing cardiac signals;

determining an adjusting characteristic associated with the cardiac signals sensed over a predetermined sensing window; and

updating the sensing parameter in response to the determined adjusting characteristic.

12. The method of claim 11, further comprising:

defining a plurality of sub-segments associated with the sensing window; and

determining the adjusting characteristic associated with the cardiac signals within each sub-segment of the plurality of sub-segments.

13. The method of claim 11, wherein the cardiac signals are sensed non-transvenously.

19. The method of claim 11, further comprising:

defining a plurality of sub-segments associated with the sensing window;

determining intervals associated with each sub-segment of the plurality of sub-segments;

determining a rate associated with each sub-segment of the plurality of sub-segments in response to the determined intervals; and

adjusting the sensing parameter in response to the determined rate associated with each sub-segment of the plurality of sub-segments.

20. The method of claim 19, further comprising determining the number of sub-segments of the plurality of sub-segments for which the sub-segment rate was determined, wherein the adjusting of the sensing parameter corresponds to the determined number of sub-segments.

21. The method of claim 11, wherein the sensing window is approximately equal to three seconds and each of the plurality of sub-segments are approximately equal to 750 ms.

14. The method of 12, wherein determining an adjusting characteristic comprises:

determining a sub-segment parameter for each of the plurality of sub-segments;

comparing the sub-segment parameter with a sub-segment parameter threshold; and

determining whether to update the sensing parameter in response to the comparing.

15. The method of claim 14, further comprising determining a sensing window parameter associated with the sensing window, wherein the sub-segment parameter threshold is equal to the determined sensing window parameter.

16. The method of claim 14, further comprising:

determining a maximum amplitude and an absolute minimum amplitude associated with the sensing window; and

comparing the maximum amplitude and the absolute minimum amplitude, wherein the sub-segment parameter and the sub-segment parameter threshold are determined in response to the comparing of the maximum amplitude and the absolute minimum amplitude.

17. The method of claim 14, further comprising:

determining a local parameter for each sub-segment of the plurality of sub-segments; and

comparing the local parameter with the sub-segment parameter.

18. The method of claim 17, wherein the sensing parameter is updated only in response to the sub-segment parameter and one or more local parameters being determined for a predetermined number of sub-segments of the plurality of sub-segments.

22. A method of updating a sensing parameter in a medical device, comprising:

sensing cardiac signals;

defining a plurality of sub-segments associated with the sensed cardiac signals sensed during a sensing window;

determining a sensing window parameter associated with the sensing window and a sub-segment parameter associated with each of the plurality of sub-segments;

comparing the sub-segment parameter for each of the plurality of sub-segments to the sensing window parameter to determine sub-segments of the plurality of sub-segments having a first adjusting characteristic;

determining a local parameter for each sub-segment of the plurality of sub-segments having the first adjusting characteristic;

comparing the local parameter to a corresponding sub-segment parameter to determine sub-segments of the plurality of sub-segments having a second adjusting characteristic; and

updating the sensing parameter in response to the determined sub-segments of the plurality of sub-segments having a second adjusting characteristic.

23. The method of claim 22, wherein the cardiac signals are sensed non-transvenously.

24. The method of claim 23, further comprising:

determining a maximum amplitude and an absolute minimum amplitude associated with the sensing window; and

comparing the maximum amplitude and the absolute minimum amplitude, wherein the sub-segment parameter and the sensing window parameter are determined in response to the comparing of the maximum amplitude and the absolute minimum amplitude.