METHOD AND APPARATUS FOR IDENTIFYING OVERSENSING USING FAR-FIELD INTRACARDIAC ELECTROGRAMS AND MARKER CHANNELS
First Claim
1. A method for identifying oversensing of cardiac events by an implantable medical device, comprising the steps of:
- detecting a near-field electrogram signal;
detecting a far-field electrograms signal;
comparing said near-field electrogram with said far-field electrogram;
identifying possible oversensing events based on a result from said comparing step; and
removing, from the possible oversensing events from the identifying step, possible oversensing events that have amplitudes above an amplitude threshold criterion and possible oversensing events that occur outside of a blanking interval period immediately after a preceding intrinsic depolarization.
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Abstract
A method for identifying and classifying various types of oversensing in implantable medical devices (IMDs), such as implantable cardioverter defibrillators (ICDs), to assist a physician in choosing corrective action to reduce the likelihood of oversensing and inappropriate therapy delivery. Far-field electrogram (EGM) signals are analyzed to detect the occurrence of R-waves, and the result is compared to the number and pattern of R-waves sensed by the IMD and indicated on the marker channel. A marker channel with more sensed R-waves than indicated by analysis of the far-field EGM indicates the presence of oversensing, including double-counting of R-waves, T-wave oversensing, lead malfunction or failure, poor lead connections, noise associated with electromagnetic interference, non-cardiac myopotentials, etc. Identification of the type of oversensing may be determined by analysis of the number and pattern of marker channel sensed R-waves with respect to the timing of the R-waves detected from the far-field EGM.
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Citations
43 Claims
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1. A method for identifying oversensing of cardiac events by an implantable medical device, comprising the steps of:
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detecting a near-field electrogram signal; detecting a far-field electrograms signal; comparing said near-field electrogram with said far-field electrogram; identifying possible oversensing events based on a result from said comparing step; and removing, from the possible oversensing events from the identifying step, possible oversensing events that have amplitudes above an amplitude threshold criterion and possible oversensing events that occur outside of a blanking interval period immediately after a preceding intrinsic depolarization. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for identifying intrinsic depolarizations of a heart chamber by an implantable medical device, comprising the steps of:
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detecting a near-field electrogram signal; detecting a far-field electrograms signal; comparing said near-field electrogram with said far-field electrogram; and marking, from possible oversensing events from a result of the comparing step, possible oversensing events that have amplitudes below an amplitude threshold criterion and possible oversensing events that occur within of a blanking interval period immediately after a preceding intrinsic depolarization. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of detecting the occurrence of intrinsic depolarizations of a heart chamber comprising:
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obtaining a far-field electrogram signal comprising a stream of digital sample points; generating identified possible intrinsic depolarizations by applying amplitude change criteria to subsets of the stream of digital sample points, the subsets comprising at least three digital sample points within the stream; removing, from the identified possible intrinsic depolarizations, possible intrinsic depolarizations that occur within a blanking interval period immediately after a preceding intrinsic depolarization to generate first updated identified possible intrinsic depolarizations;
thenremoving, from the first updated identified possible intrinsic depolarizations, possible intrinsic depolarizations that have amplitudes below an amplitude threshold criterion to generate second updated identified possible depolarizations; and marking the second updated identified possible intrinsic depolarizations as sensed events from the far-field electrogram signal. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. A method for identifying oversensing of cardiac events, comprising the steps of:
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obtaining a far-field electrogram signal comprising a stream of digital sample points; generating identified possible intrinsic depolarizations by applying amplitude change criteria to subsets of the stream of digital sample points, the subsets comprising at least three digital sample points within the stream; marking, from the identified possible intrinsic depolarizations, possible intrinsic depolarizations that occur outside of a blanking interval period immediately after a preceding intrinsic depolarization to generate first updated identified possible intrinsic depolarizations;
thenmarking, from the first updated identified possible intrinsic depolarizations, possible intrinsic depolarizations that have amplitudes above an amplitude threshold criterion to denote sensed events from the far-field electrogram signal. - View Dependent Claims (27, 28, 29, 30, 31, 36)
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37. A method for identifying oversensing of cardiac events, comprising the steps of:
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obtaining a far-field electrogram signal comprising a stream of digital sample points; generating identified possible intrinsic depolarizations by applying amplitude change criteria to subsets of the stream of digital sample points, the subsets comprising at least three digital sample points within the stream; marking, from the identified possible intrinsic depolarizations, possible intrinsic depolarizations that have amplitudes above an amplitude threshold criterion to generate first updated identified possible intrinsic depolarizations;
thenmarking, from the first updated identified possible intrinsic depolarizations, possible intrinsic depolarizations that occur outside of a blanking interval period immediately after a preceding intrinsic depolarization to denote sensed events from the far-field electrogram signal. - View Dependent Claims (38, 39, 40, 41, 42, 43)
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Specification