System and method for avoiding undersensing of ventricular fibrillation
First Claim
1. A medical device for detecting and treating tachyarrhythmia, comprising:
- a plurality of electrodes to sense a cardiac signal;
a sensing module coupled to the plurality of electrodes to sense cardiac events in response to the cardiac signal;
a first processing module coupled to the sensing module and configured to;
determine a first morphology metric for each sensed cardiac event occurring during a time segment of the cardiac signal;
determine a count of the first morphology metrics corresponding to an event originating in a ventricular chamber;
determine a second morphology metric for the time segment of the cardiac signal in response to the count of the first morphology metrics meeting a threshold number of events; and
classify the time segment as a shockable segment in response to the second morphology metric meeting a detection criterion;
the first processing module further configured to generate only a ventricular fibrillation detection signal in response to the time segment being classified as a shockable segment;
a second processing module configured to determine a number of tachyarrhythmia intervals between the sensed cardiac events in parallel to the first processing module computing of the first morphology metrics,the second processing module further configured to detect a tachyarrhythmia in response to determining the number of tachyarrhythmia intervals; and
override the tachyarrhythmia detection when a shockable rhythm is detected by the first processing module in response to the number of time segments meeting the detection threshold.
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Accused Products
Abstract
A medical device and associated method for detecting and treating tachyarrhythmias acquires a cardiac signal using electrodes coupled to a sensing module. Cardiac events are sensed from the cardiac signal and a processing module computes a first morphology metric for each sensed cardiac event occurring during a time segment of the cardiac signal. The first morphology metrics corresponding to an event originating in a ventricular chamber are counted. The first processing module computes a second morphology metric for the time segment of the cardiac signal in response to the count of the first morphology metrics meeting a threshold number of events. The time segment is classified as a shockable segment in response to the second morphology metric meeting a detection criterion.
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Citations
11 Claims
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1. A medical device for detecting and treating tachyarrhythmia, comprising:
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a plurality of electrodes to sense a cardiac signal; a sensing module coupled to the plurality of electrodes to sense cardiac events in response to the cardiac signal; a first processing module coupled to the sensing module and configured to; determine a first morphology metric for each sensed cardiac event occurring during a time segment of the cardiac signal; determine a count of the first morphology metrics corresponding to an event originating in a ventricular chamber; determine a second morphology metric for the time segment of the cardiac signal in response to the count of the first morphology metrics meeting a threshold number of events; and classify the time segment as a shockable segment in response to the second morphology metric meeting a detection criterion; the first processing module further configured to generate only a ventricular fibrillation detection signal in response to the time segment being classified as a shockable segment; a second processing module configured to determine a number of tachyarrhythmia intervals between the sensed cardiac events in parallel to the first processing module computing of the first morphology metrics, the second processing module further configured to detect a tachyarrhythmia in response to determining the number of tachyarrhythmia intervals; and override the tachyarrhythmia detection when a shockable rhythm is detected by the first processing module in response to the number of time segments meeting the detection threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A non-transitory, computer-readable medium storing a set of instructions, which when executed by a processor of a medical device causes the device to:
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determining a cardiac signal using a plurality of electrodes coupled to a sensing module; determine cardiac events in response to the cardiac signal; determine a first morphology metric for each sensed cardiac event occurring during a time segment of the cardiac signal; determine a count of the first morphology metrics corresponding to an event originating in a ventricular chamber; determine a second morphology metric for the time segment of the cardiac signal in response to the count of the first morphology metrics meeting a threshold number of events; and classify the time segment as a shockable segment in response to the second morphology metric meeting a detection criterion; and generate only a ventricular fibrillation detection signal in response to the time segment being classified as a shockable segment determine a number of tachyarrhythmia intervals between the sensed cardiac events in parallel to the computing of the first morphology metrics, detect a tachyarrhythmia in response to determining the number of tachyarrhythmia intervals; and override the tachyarrhythmia detection when a shockable rhythm is detected by the first processing module in response to the number of time segments meeting the detection threshold.
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11. A medical device, comprising:
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a plurality of electrodes; a sensing module coupled to the plurality of electrodes for sensing a cardiac signal; a therapy delivery module coupled to the plurality of electrode for delivering a therapy; a first processing module coupled to the sensing module and configured to; determine a first morphology metric for each individual one of a plurality of cardiac events occurring during a time segment of the cardiac signal, classify each individual one of the plurality of cardiac events as at least one of a supraventricular beat and a ventricular beat by comparing each of the first morphology metrics to beat classification criteria, responsive to a minimum number of the individual ones of the plurality of cardiac events being classified as ventricular beats, determining a second morphology metric by analyzing signal samples across the n-second segment independent of identifying the cardiac events, classify the time segment as a shockable segment in response to the second morphology metric meeting a detection criterion, and generate an output signal in response to the time segment being classified as a shockable segment wherein the output signal is only a ventricular fibrillation detection output signal; and a second processing module coupled to the sensing module and configured to; determine intervals between cardiac events of the cardiac signal in parallel to the first processing module determining the first morphology metrics, determine a count of the determined intervals meeting tachyarrhythmia criteria, in response to the count meeting ventricular tachycardia criteria determining a third morphology metric of the cardiac signal, and generate an output signal selected from a supraventricular tachycardia output signal, a ventricular tachycardia output signal, and a ventricular fibrillation output signal in response to the count meeting the tachyarrhythmia criteria and in response to the morphology metric if it is determined; and a control module configured to receive the first processing module output signal and the second processing module output signal and make a therapy decision for controlling the therapy delivery module based on the first processing module output signal and the second processing output signal.
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Specification