T-wave oversensing rejection
First Claim
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1. A method performed by a medical device, comprising:
- receiving a cardiac electrical signal from a patient'"'"'s heart via a plurality of extracardiac electrode electrically coupled to the medical device;
sensing cardiac events from the cardiac electrical signal;
during a first operating state of the medical device, determining an estimated rate of the sensed cardiac events;
transitioning from the first operating state to a second operating state of the medical device when the estimated rate of cardiac events meets a shockable rate detection criterion;
setting a first signal analysis segment of the cardiac electrical signal during the second operating state;
analyzing the first signal analysis segment to determine if shockable rhythm classification criteria are met for the first signal analysis segment;
setting a plurality of T-wave oversensing (TWOS) analysis windows;
analyzing cardiac events of the cardiac electrical signal to classify each TWOS analysis window of the plurality of TWOS analysis windows as one of TWOS and no TWOS, each TWOS analysis window being classified as TWOS when cardiac events during the TWOS analysis window satisfy TWOS criteria and classified as no TWOS when the cardiac events during the TWOS analysis window do not satisfy TWOS criteria;
determining that TWOS detection criteria are met for the first signal analysis segment when a predetermined number of the plurality of TWOS analysis windows are classified as TWOS;
classifying the first signal analysis segment as non-shockable in response to determining that the TWOS detection criteria are met; and
remaining in the second operating state without advancing to a third operating state of the medical device when the TWOS detection criteria are met for the first signal analysis segment.
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Abstract
A medical device coupled to extracardiac electrodes is configured to analyze a cardiac electrical signal over a signal analysis segment to determine if shockable rhythm classification criteria are met, determine that TWOS detection criteria are met for the signal analysis segment when a predetermined number of TWOS analysis windows are classified as TWOS, and classify the signal analysis segment as non-shockable in response to determining that the TWOS detection criteria are met.
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Citations
18 Claims
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1. A method performed by a medical device, comprising:
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receiving a cardiac electrical signal from a patient'"'"'s heart via a plurality of extracardiac electrode electrically coupled to the medical device; sensing cardiac events from the cardiac electrical signal; during a first operating state of the medical device, determining an estimated rate of the sensed cardiac events; transitioning from the first operating state to a second operating state of the medical device when the estimated rate of cardiac events meets a shockable rate detection criterion; setting a first signal analysis segment of the cardiac electrical signal during the second operating state; analyzing the first signal analysis segment to determine if shockable rhythm classification criteria are met for the first signal analysis segment; setting a plurality of T-wave oversensing (TWOS) analysis windows; analyzing cardiac events of the cardiac electrical signal to classify each TWOS analysis window of the plurality of TWOS analysis windows as one of TWOS and no TWOS, each TWOS analysis window being classified as TWOS when cardiac events during the TWOS analysis window satisfy TWOS criteria and classified as no TWOS when the cardiac events during the TWOS analysis window do not satisfy TWOS criteria; determining that TWOS detection criteria are met for the first signal analysis segment when a predetermined number of the plurality of TWOS analysis windows are classified as TWOS; classifying the first signal analysis segment as non-shockable in response to determining that the TWOS detection criteria are met; and remaining in the second operating state without advancing to a third operating state of the medical device when the TWOS detection criteria are met for the first signal analysis segment. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An implantable medical device, comprising:
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a sensing module configured to receive a cardiac electrical signal via a plurality of extracardiac electrodes coupled to the implantable medical device ; and a control module coupled to the sensing module and configured to; set a first signal analysis segment of the cardiac electrical signal; analyze the first signal analysis segment to determine if shockable rhythm classification criteria are met for the first signal analysis segment set a plurality of T-wave oversensing (TWOS) analysis windows; analyze cardiac events of the cardiac electrical signal to classify each TWOS analysis window of the plurality of TWOS analysis windows as one of TWOS and no TWOS, each TWOS analysis window being classified as TWOS when cardiac events during the TWOS analysis window satisfy TWOS criteria and classified as no TWOS when the cardiac events during the TWOS analysis window do not satisfy TWOS criteria; determine that TWOS detection criteria are met for the first signal analysis segment when a predetermined number of the plurality of TWOS analysis windows are classified as TWOS, wherein the control module is further configured to determine whether the TWOS detection criteria are met for the first signal analysis segment only after the shockable rhythm classification criteria are met for the first signal analysis segment; and classify the first signal analysis segment as non-shockable in response to determining that the TWOS detection criteria are met.
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11. An implantable medical device, comprising:
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a sensing module configured to receive a cardiac electrical signal via a plurality of extracardiac electrodes coupled to the implantable medical device ; and a control module coupled to the sensing module and configured to; set a first signal analysis segment of the cardiac electrical signal; analyze the first signal analysis segment to determine if shockable rhythm classification criteria are met for the first signal analysis segment; set a plurality of T-wave oversensing (TWOS) analysis windows; analyze cardiac events of the cardiac electrical signal to classify each TWOS analysis window of the plurality of TWOS analysis windows as one of TWOS and no TWOS, each TWOS analysis window being classified as TWOS when cardiac events during the TWOS analysis window satisfy TWOS criteria and classified as no TWOS when the cardiac events during the TWOS analysis window do not satisfy TWOS criteria; determine that TWOS detection criteria are met for the first signal analysis segment when a predetermined number of the plurality of TWOS analysis windows are classified as TWOS; and classify the first signal analysis segment as non-shockable in response to determining that the TWOS detection criteria are met, wherein; the sensing module is configured to sense cardiac events from the cardiac electrical signal; the control module is further configured to; determine an estimated rate of the sensed cardiac events during a first operating state of the medical device; transition from the first operating state to a second operating state of the medical device when the estimated rate of cardiac events meets a shockable rate detection criterion; set the first signal analysis segment during the second operating state; and remain in the second operating state without advancing to a third operating state of the medical device when the TWOS detection criteria are met for the first signal analysis segment.
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12. An implantable medical device, comprising:
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a sensing module configured to receive a cardiac electrical signal via a plurality of extracardiac electrodes coupled to the implantable medical device; and a control module coupled to the sensing module and configured to; set a first signal analysis segment of the cardiac electrical signal; analyze the first signal analysis segment to determine if shockable rhythm classification criteria are met for the first signal analysis segment; set a plurality of T-wave oversensing (TWOS) analysis windows; analyze cardiac events of the cardiac electrical signal to classify each TWOS analysis window of the plurality of TWOS analysis windows as one of TWOS and no TWOS, each TWOS analysis window being classified as TWOS when cardiac events during the TWOS analysis window satisfy TWOS criteria and classified as no TWOS when the cardiac events during the TWOS analysis window do not satisfy TWOS criteria; determine that TWOS detection criteria are met for the first signal analysis segment when a predetermined number of the plurality of TWOS analysis windows are classified as TWOS; and classify the first signal analysis segment as non-shockable in response to determining that the TWOS detection criteria are met, wherein the control module is further configured to classify a second signal analysis segment preceding the first signal analysis segment as non-shockable when the TWOS detection criteria are met for the first signal analysis segment. - View Dependent Claims (13, 14, 15)
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16. An implantable medical device, comprising:
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a sensing module configured to receive a cardiac electrical signal via a plurality of extracardiac electrodes coupled to the implantable medical device ; and a control module coupled to the sensing module and configured to; set a first signal analysis segment of the cardiac electrical signal; analyze the first signal analysis segment to determine if shockable rhythm classification criteria are met for the first signal analysis segment; set a plurality of T-wave oversensing (TWOS) analysis windows; analyze cardiac events of the cardiac electrical signal to classify each TWOS analysis window of the plurality of TWOS analysis windows as one of TWOS and no TWOS, each TWOS analysis window being classified as TWOS when cardiac events during the TWOS analysis window satisfy TWOS criteria and classified as no TWOS when the cardiac events during the TWOS analysis window do not satisfy TWOS criteria, wherein the control module is configured to analyze the cardiac events of the cardiac electrical signal by; selecting at least one group of at least three consecutive cardiac events from the plurality of cardiac events that are within a given one of the plurality of TWOS analysis windows; determining a maximum event amplitude from the at least one group; determining an event discrimination threshold using the maximum event amplitude; and identifying as R-waves all cardiac events of the plurality of cardiac events within the given one of the plurality of TWOS analysis windows that are equal to or greater than the event discrimination threshold; identifying as T-waves all events of the plurality of cardiac events within the given one of the plurality of TWOS analysis windows that have a maximum signal amplitude that is less than the event discrimination threshold; and identifying a pattern of TWOS when each one of at least a portion of the identified R-waves is consecutively followed by one of the identified T-waves in an R-T pair; determine that TWOS detection criteria are met for the first signal analysis segment when a predetermined number of the plurality of TWOS analysis windows are classified as TWOS; and classify the first signal analysis segment as non-shockable in response to determining that the TWOS detection criteria are met. - View Dependent Claims (17)
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18. An implantable medical device, comprising:
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a sensing module configured to receive a cardiac electrical signal via a plurality of extracardiac electrodes coupled to the implantable medical device ; and a control module coupled to the sensing module and configured to; set a first signal analysis segment of the cardiac electrical signal; analyze the first signal analysis segment to determine if shockable rhythm classification criteria are met for the first signal analysis segment; set a plurality of T-wave oversensing (TWOS) analysis windows; analyze cardiac events of the cardiac electrical signal to classify each TWOS analysis window of the plurality of TWOS analysis windows as one of TWOS and no TWOS, each TWOS analysis window being classified as TWOS when cardiac events during the TWOS analysis window satisfy TWOS criteria and classified as no TWOS when the cardiac events during the TWOS analysis window do not satisfy TWOS criteria; determine that TWOS detection criteria are met for the first signal analysis segment when a predetermined number of the plurality of TWOS analysis windows are classified as TWOS, wherein the control module is configured to determine that the TWOS detection criteria are met for the first signal analysis segment by determining that the TWOS detection criteria are met when a first predetermined number of the plurality of TWOS analysis windows are classified as TWOS and a second predetermined number of the plurality of TWOS analysis windows that are classified as TWOS occur within a third predetermined number of the plurality of TWOS analysis windows preceding the shockable rhythm classification criteria being met; and classify the first signal analysis segment as non-shockable in response to determining that the TWOS detection criteria are met.
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Specification