Method and apparatus for identifying cardiac and non-cardiac oversensing using intracardiac electrograms

• US 20030204215A1
• Filed: 04/29/2002
• Published: 10/30/2003
• Est. Priority Date: 04/29/2002
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Gunderson, Bruce D., Patel, Amisha S., Bounds, Chad A.
• Granted Patent: US 7,283,863 B2
• 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 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting

Abstract

A method and apparatus for automatically identifying various types of cardiac and non-cardiac 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.

Claims

1. A processor readable medium containing a system of instructions to cause the processor to identify cardiac and non-cardiac oversensing using intracardiac electrograms, the system comprising:

an implantable medical device (IMD) containing EGM data;

means for accessing said EGM data;

means for performing analysis of said EGM data;

means for identifying oversensing based on said analysis of said EGM data; and

means for recommending a corrective action based on at least one characteristic of an identified oversensing to implement said corrective action in said IMD.

2. The system of claim 1 wherein said EGM data relates to data collected by an arrhythmia detection means.

3. The system of claim 1 wherein said EG data relates to data collected by monitoring means.

4. The system of claim 1 wherein said means for accessing includes one of a programmer, a personal computer and an external device in data communication with the said IMD.

5. The system of claim 1 wherein said EGM includes EGM signal, sensed and/or paced interval data, and annotations of sensed and/or paced events.

6. The system of claim 4 wherein one of said programmer, said personal computer and said external device is implemented to perform said analysis of said EGM data.

7. The system of claim 1 wherein said means for accessing is implemented in said IMD.

8. The system of claim 1 wherein said means for performing analysis is implemented in said IMD.

9. The system of claim 1 wherein said means for recommending a corrective action is implemented in said IMD.

10. The system of claim 9 wherein said corrective action includes warning a patient via a notification means.

11. The system of claim 10 wherein said corrective action includes one of reprogramming a sensitivity setting, reprogramming a sensing electrode configuration, tightening set screws in the connector block, investigating for a likely lead fracture to thereby repair or replace, and implement investigation to eliminate oversensing.

12. A processor readable medium containing instructions to cause a processor in an IMD to determine oversensing and take corrective action, the processor-implemented instructions and the IMD, in combination, comprising:

means for detecting arrhythmia;

means for performing EGM analysis on said arrhythmia;

means for identifying oversensing based on an analysis of said arrhythmia;

means for suspending therapy if oversensing is identified;

means for triggering EGM storage in the IMD;

means for canceling therapy; and

means for notifying a patient;

said means for detecting being in data communication with said means for performing EGM analysis to identify oversensing by said means for identifying to suspend therapy delivery, if oversensing is detected, by activating said means for suspending therapy to thereafter store said EGM in the IMD via said means for triggering EGM storage and thereafter identify therapy cancellation by said means for canceling therapy and notifying the patient via said means for notifying.

13. The combination of claim 12 wherein said means for notifying a patient includes means for generating perceptible stimuli.

14. A method for identifying cardiac and non-cardiac oversensing for cardiac episodes, the method comprising:

detecting at least one cardiac episode;

discriminating between induced and spontaneous arrhythmia episodes to identify appropriate detection;

identifying oversensing based on one of far-field R-wave (FFRW) oversensing, T-wave oversensing and R-wave oversensing; and

assessing noise and sinus rhythm patterns to determine one of appropriate detection, EMI, poor lead connection, lead fracture and myopotential noise.

15. The method of claim 14 wherein said detecting at least one cardiac episode includes distinguishing between VF and FFRW.

16. The method of claim 14 wherein said discriminating between induced and spontaneous includes classifying induced episodes as said appropriate detection.

17. The method of claim 14 wherein said assessing noise and sinus rhythm includes checking if saturation or noise burst on near field EGM exist to determine said one of poor lead connection and lead fracture.

18. The method of claim 17 wherein said poor lead connection is indicated if a lead implant is less than two months old.

19. The method of claim 17 wherein said lead fracture is indicated if a lead implant is greater than two months old.

20. A method for recognizing a pattern indicative of oversensing, comprising:

initializing an internal counter to a value of zero;

initializing an oversense counter to a value of zero;

comparing a plurality of R-R intervals to a sensed R-R interval;

comparing a value of an oversense interval counter to a number of intervals evaluated; and

checking if said number of intervals satisfy a cardiac oversensing pattern.

21. A method of performing morphology analysis of waveform data for a cardiac episode, the method comprising:

storing at least one morphology template;

storing a morphology of a sensed event as a first template;

comparing said at least one morphology template to said first template;

comparing a morphology of a sensed event prior to said sensed event stored as a first template; and

storing as a second template if there is a mismatch between said first template and said event prior thereto.

22. A method for identifying noise artifacts to indicate lead fracture or poor lead connections, the method comprising:

identifying low frequency segments;

identifying noise segments within said low frequency segment;

determining a number of low frequency groups; and

deciding the presence or absence of noise burst based on evaluation of largest low frequency group compared to a segments metric, a maximum noise segment compared to noise units metric, and total EGM signal compared to a percentage of noise metric.