METHOD AND APPARATUS FOR IDENTIFYING CARDIAC AND NON-CARDIAC OVERSENSING USING INTRACARDIAC ELECTROGRAMS

• US 20100280567A1
• Filed: 07/13/2010
• Published: 11/04/2010
• Est. Priority Date: 04/29/2002
• Status: Abandoned Application

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Gunderson, Bruce D.
• Application Number:
  US12/835,027
• Publication Number:
  US 20100280567A1
• Time in Patent Office: Days
• US Class Current: 607/27
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting

Abstract

A method and apparatus for automatically identifying various types of cardiac and non-cardiac oversensing and automatically performing a corrective action to reduce the likelihood of oversensing is provided. EGM data, including time intervals between sensed and paced events and signal morphologies, are analyzed for patterns indicative of various types of oversensing, including oversensing of far-field R-waves, R-waves, T-waves, or noise associated with electromagnetic interference, non-cardiac myopotentials, a lead fracture, or a poor lead connection. Identification of oversensing and its suspected cause are reported so that corrective action may be taken. The corrective action may include, for example, adjusting sensing parameters such as blanking periods, decay constants, decay delays, threshold values, sensitivity values, electrode configurations and the like.

Claims

1. A method of operating an implantable medical device comprising:

detecting an arrhythmia of a heart of a patient;

identifying the detected arrhythmia as an inappropriate detection due to oversensing; and

cancelling a therapy upon identifying the detected arrhythmia as an inappropriate detection due to oversensing.

2. The method of claim 1, further comprising automatically performing a corrective action to prevent future inappropriate arrhythmia detections in response to identifying the detected arrhythmia as an inappropriate detection due to oversensing.

3. The method of claim 2, further comprising identifying an origin of oversensing, wherein automatically performing the corrective action comprises automatically performing the corrective action based on the identified origin.

4. The method of claim 3, wherein identifying the origin of the oversensing comprises identifying the origin as one of cardiac origin and non-cardiac origin.

5. The method of claim 3, wherein identifying the origin of the oversensing comprises one of identifying the origin of oversensing as one of far-field R-wave oversensing, T-wave oversensing, R-wave oversensing, poor lead connection, lead fracture, electromagnetic interference (EMI) and myopotential noise.

6. The method of claim 2, wherein automatically performing the corrective action comprises automatically adjusting at least one sensing parameter of the implanted medical device in response to identifying the detected arrhythmia as an inappropriate detection due to oversensing.

7. The method of claim 6, wherein automatically adjusting the at least one sensing parameter includes automatically adjusting at least one of a programmed sensitivity of a sensing electrode, a programmed threshold of a sensing electrode, a programmed decay constant of a sensing electrode, a programmed decay delay of a sensing electrode, a programmed blanking period of a sensing electrode, and an electrode configuration of a sensing electrode.

8. The method of claim 2, wherein the automatic corrective action is performed iteratively and incrementally, and after each adjustment determining whether oversensing persists.

9. The method of claim 1, wherein identifying the detected arrhythmia as an inappropriate detection due to oversensing comprises:

determining whether a sum of consecutive interval differences is less than a predetermined maximum;

determining whether an interval pattern is indicative of cardiac oversensing;

determining whether signal morphologies of consecutively sensed events alternate; and

identifying the detected arrhythmia as an inappropriate detection due to oversensing when the sum of consecutive interval differences is not less than the predetermined maximum, the interval pattern is indicative of cardiac oversensing, and alternating signal morphologies occur.

10. The method of claim 9, further comprising:

analyzing consecutive intervals to determine whether there are alternating short and long intervals; and

identifying the detected arrhythmia as an inappropriate detection due to oversensing when the sum of consecutive interval differences is not less than the predetermined maximum, the interval pattern is indicative of cardiac oversensing, alternating signal morphologies do not occur, and consecutive intervals have alternating short and long intervals.

11. The method of claim 1, wherein identifying the detected arrhythmia as an inappropriate detection due to oversensing comprises identifying the detected arrhythmia as an inappropriate detection due to oversensing using intracardiac electrograms.

12. An implantable medical device comprising:

sensing circuitry that obtains signals sensed by one or more electrodes; and

a processor that analyzes the sensed signals to detect an arrhythmia of a heart of a patient;

identify the detected arrhythmia as an inappropriate detection due to oversensing, and cancel a therapy upon identifying the detected arrhythmia as an inappropriate detection due to oversensing.

13. The device of claim 12, wherein the processor automatically performs a corrective action to prevent future inappropriate arrhythmia detections in response to identifying the detected arrhythmia as an inappropriate detection due to oversensing.

14. The device of claim 13, wherein the processor identifies an origin of oversensing, wherein automatically performing the corrective action comprises automatically performing the corrective action based on the identified origin.

15. The device of claim 14, wherein the origin of the oversensing is identified as one of cardiac origin and non-cardiac origin.

16. The device of claim 14, wherein the origin of the oversensing is identified as one of far-field R-wave oversensing, T-wave oversensing, R-wave oversensing, poor lead connection, lead fracture, electromagnetic interference (EMI) and myopotential noise.

17. The device of claim 13, wherein the processor automatically adjusts at least one sensing parameter of the implanted medical device in response to identifying the detected arrhythmia as an inappropriate detection due to oversensing.

18. The device of claim 17, wherein the processor automatically adjusts at least one of a programmed sensitivity of the sensing circuitry, a programmed blanking period of the sensing circuitry, a programmed threshold of the sensing circuitry, a programmed decay constant of the sensing circuitry, a programmed decay delay of the sensing circuitry, and an electrode configuration.

19. The device of claim 13, wherein the processor performs the corrective action iteratively and incrementally, and after each adjustment determines whether oversensing persists.

20. The device of claim 12, wherein the processor:

determines whether a sum of consecutive interval differences is less than a predetermined maximum;

determines whether an interval pattern is indicative of cardiac oversensing;

determines whether signal morphologies of consecutively sensed events alternate; and

identifies the detected arrhythmia as an inappropriate detection due to oversensing when the sum of consecutive interval differences is not less than the predetermined maximum, the interval pattern is indicative of cardiac oversensing, and alternating signal morphologies occur.

21. The device of claim 20, wherein the processor:

analyzes consecutive intervals to determine whether there are alternating short and long intervals; and

identifies the detected arrhythmia as an inappropriate detection due to oversensing when the sum of consecutive interval differences is not less than the predetermined maximum, the interval pattern is indicative of cardiac oversensing, alternating signal morphologies do not occur, and consecutive intervals have alternating short and long intervals.

22. An implantable medical device comprising:

means for detecting an arrhythmia of a heart of a patient;

means for identifying the detected arrhythmia as an inappropriate detection due to oversensing; and

means for cancelling a therapy upon identifying the detected arrhythmia as an inappropriate detection due to oversensing.

23. The device of claim 22, further comprising means for automatically performing a corrective action to prevent future inappropriate arrhythmia detections in response to identifying the detected arrhythmia as an inappropriate detection due to oversensing.

24. The device of claim 23, wherein the identifying means identify an origin of oversensing and the means for automatically performing the corrective action perform the corrective action based on the identified origin.

25. A computer-readable medium comprising instructions that when executed by a processor cause the processor to:

detect an arrhythmia of a heart of a patient;

identify the detected arrhythmia as an inappropriate detection due to oversensing; and

cancel a therapy upon identifying the detected arrhythmia as an inappropriate detection due to oversensing.