METHOD AND APPARATUS FOR DETECTING ARRHYTHMIAS IN A MEDICAL DEVICE

• US 20080275516A1
• 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 8,068,901 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• 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 of updating a sensing parameter in a medical device that includes sensing cardiac signals, determining intervals in response to the sensed cardiac signals, determining interval patterns associated with the determined intervals, and updating the sensing parameter in response to the determined interval patterns.

Claims

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

means for sensing cardiac signals;

means for determining intervals in response to the sensed cardiac signals;

means for determining interval patterns associated with the determined intervals; and

means for updating the sensing parameter in response to the determined interval patterns.

2. The apparatus of claim 1, wherein the means for determining interval patterns comprises means for sorting the determined intervals from a smallest interval to a largest interval, and wherein the means for updating the sensing parameter comprises:

means for determining a first mean of a first predetermined number of the sorted determined intervals;

means for determining a second mean of a second predetermined number of the sorted determined intervals, each interval of the second predetermined number of intervals being greater than intervals of the first predetermined number of the sorted determined interval; and

means for determining a sum of the determined first mean and the determined second mean.

3. The apparatus of claim 1, wherein the means for determining interval patterns comprises means for sorting the determined intervals from a smallest interval to a largest interval, and wherein the means for updating the sensing parameter comprises:

means for determining a spectral width associated with the determined intervals; and

means for determining a sum of the spectral width and a predetermined interval of the determined intervals.

4. The apparatus of claim 1, further comprising means for updating the determined intervals in response to the determined interval patterns, wherein the sensing parameter is updated in response to the updated intervals.

5. The apparatus of claim 1, wherein the cardiac signals are sensed non-transveneously.

6. The apparatus of claim 1, wherein the adjusting of the sensing parameter is in response to oversensing being determined by the apparatus.

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

sensing cardiac signals;

determining intervals in response to the sensed cardiac signals;

determining interval patterns associated with the determined intervals; and

updating the sensing parameter in response to the determined interval patterns.

8. The method of claim 7, wherein determining interval patterns comprises sorting the determined intervals from a smallest interval to a largest interval, and wherein updating the sensing parameter comprises:

determining a first mean of a first predetermined number of the sorted determined intervals;

determining a second mean of a second predetermined number of the sorted determined intervals, each interval of the second predetermined number of intervals being greater than intervals of the first predetermined number of the sorted determined interval; and

determining a sum of the determined first mean and the determined second mean.

9. The method of claim 7, wherein determining interval patterns comprises sorting the determined intervals from a smallest interval to a largest interval, and wherein updating the sensing parameter comprises:

determining a spectral width associated with the determined intervals; and

determining a sum of the spectral width and a predetermined interval of the determined intervals.

10. The method of claim 7, further comprising updating the determined intervals in response to the determined interval patterns, wherein the sensing parameter is updated in response to the updated intervals.

11. The method of claim 7, wherein the cardiac signals are sensed non-transveneously.

12. The method of claim 7, wherein the adjusting of the sensing parameter is in response to oversensing being determined.

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

sensing cardiac signals to identify a cardiac event using the sensing parameter;

storing a plurality of intervals in response to the sensed cardiac signals;

comparing a first interval of the plurality of intervals with an interval threshold;

generating updated intervals in response to the comparing; and

updating the sensing parameter in response to the generated updated intervals.

14. The method of claim 13, further comprising verifying the identification of the cardiac event in response to the updated sensing parameter.

15. The method of claim 13, wherein generating updated intervals comprises setting a next updated interval equal to a sum of the first interval and a second interval of the plurality of intervals subsequent to the first interval in response to the first interval being less than the interval threshold.

16. The method of claim 15, wherein generating updated intervals further comprises setting the next updated interval equal to the first interval in response to the first interval not being less than the interval threshold.

17. The method of claim 13, wherein the interval threshold corresponds to a sum of a blanking period and a rate correction constant.

18. The method of claim 17, wherein the interval threshold corresponds to a maximum width of the cardiac event.

19. The method of claim 13, wherein generating updated intervals comprises:

comparing a second interval of the plurality of intervals to the interval threshold in response to the first interval being less than the interval threshold; and

setting a next updated interval equal to a sum of the first interval and the second interval in response to the second interval not being less than the interval threshold.

20. The method of claim 19, wherein generating updated intervals further comprises setting the next updated interval equal to the first interval in response to the second interval being less than the interval threshold.

21. The method of claim 19, wherein the interval threshold corresponds to a maximum width of the cardiac event.

22. The method of claim 13, wherein the cardiac signals are sensed non-transveneously.

23. The method of claim 13, wherein the adjusting of the sensing parameter is in response to oversensing being determined.