Methods and Devices for Adapting Charge Initiation for an Implantable Defibrillator
First Claim
1. A method of avoiding inappropriate therapy delivery to a patient in an implantable defibrillator, the implantable defibrillator comprising a number of implantable electrodes and operational circuitry for performing cardiac signal analysis and therapy delivery using the implantable electrodes, the method comprising, at a first time:
- detecting cardiac events in a patient using the implantable electrodes;
filling an X-out-of-Y filter with data related to the detected cardiac events and using the X-out-of-Y filter to determine that X exceeds a predetermined treatment threshold;
when X exceeds the predetermined treatment threshold, using a predetermined persistence threshold, N, and applying a persistence rule calling for X to exceed the predetermined treatment threshold for at least N consecutive cardiac events;
when the persistence rule is met, initiating a charging sequence to charge a capacitor for therapy delivery;
after initiating the charging sequence but before therapy delivery, determining that the cardiac signal data of the patient no longer indicates a need for therapy; and
upon determining, after initiating the charging sequence but before therapy delivery, that the cardiac signal data of the patient no longer indicates a need for therapy, modifying N to increase the quantity of consecutive cardiac events required to meet the persistence threshold and storing N for use in the future;
and the method further comprising, at a second time;
detecting cardiac events in the patient using the implantable electrodes;
filling the X-out-of-Y filter with data related to the detected cardiac events and using the X-out-of-Y filter to determine that X exceeds a predetermined treatment threshold;
when X exceeds the predetermined treatment threshold, applying the persistence rule calling for X to exceed the predetermined treatment threshold for at least N consecutive cardiac events, wherein N, when applied at the second time, is modified in view of the occurrence of the first time; and
finding that the persistence rule is not met due to the increase in N at least once.
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Abstract
Adaptive methods for initiating charging of the high power capacitors of an implantable medical device for therapy delivery after the patient experiences a non-sustained arrhythmia, and devices that perform such methods. The adaptive methods and devices adjust persistence criteria used to analyze an arrhythmia prior to initiating a charging sequence to deliver therapy. Some embodiments apply a specific sequence of X-out-of-Y criteria, persistence criteria, and last event criteria before starting charging for therapy delivery.
33 Citations
11 Claims
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1. A method of avoiding inappropriate therapy delivery to a patient in an implantable defibrillator, the implantable defibrillator comprising a number of implantable electrodes and operational circuitry for performing cardiac signal analysis and therapy delivery using the implantable electrodes, the method comprising, at a first time:
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detecting cardiac events in a patient using the implantable electrodes; filling an X-out-of-Y filter with data related to the detected cardiac events and using the X-out-of-Y filter to determine that X exceeds a predetermined treatment threshold; when X exceeds the predetermined treatment threshold, using a predetermined persistence threshold, N, and applying a persistence rule calling for X to exceed the predetermined treatment threshold for at least N consecutive cardiac events; when the persistence rule is met, initiating a charging sequence to charge a capacitor for therapy delivery; after initiating the charging sequence but before therapy delivery, determining that the cardiac signal data of the patient no longer indicates a need for therapy; and upon determining, after initiating the charging sequence but before therapy delivery, that the cardiac signal data of the patient no longer indicates a need for therapy, modifying N to increase the quantity of consecutive cardiac events required to meet the persistence threshold and storing N for use in the future; and the method further comprising, at a second time; detecting cardiac events in the patient using the implantable electrodes; filling the X-out-of-Y filter with data related to the detected cardiac events and using the X-out-of-Y filter to determine that X exceeds a predetermined treatment threshold; when X exceeds the predetermined treatment threshold, applying the persistence rule calling for X to exceed the predetermined treatment threshold for at least N consecutive cardiac events, wherein N, when applied at the second time, is modified in view of the occurrence of the first time; and finding that the persistence rule is not met due to the increase in N at least once. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An implantable defibrillator comprising a number of implantable electrodes and operational circuitry for performing cardiac signal analysis and therapy delivery using the implantable electrodes, the operational circuitry being configured to perform the following:
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at a first time; detecting cardiac events in a patient using the implantable electrodes; filling an X-out-of-Y filter with data related to the detected cardiac events and using the X-out-of-Y filter to determine that X exceeds a predetermined treatment threshold; when X exceeds the predetermined treatment threshold, using a predetermined persistence threshold, N, and applying a persistence rule calling for X to exceed the predetermined treatment threshold for at least N consecutive cardiac events; when the persistence rule is met, initiating a charging sequence to charge a capacitor for therapy delivery; after initiating the charging sequence but before therapy delivery, determining that the cardiac signal data of the patient no longer indicates a need for therapy; and upon determining, after initiating the charging sequence but before therapy delivery, that the cardiac signal data of the patient no longer indicates a need for therapy, modifying N to increase the quantity of consecutive cardiac events required to meet the persistence threshold and storing N for use in the future; and at a second time; detecting cardiac events in the patient using the implantable electrodes; filling the X-out-of-Y filter with data related to the detected cardiac events and using the X-out-of-Y filter to determine that X exceeds a predetermined treatment threshold; when X exceeds the predetermined treatment threshold, applying the persistence rule calling for X to exceed the predetermined treatment threshold for at least N consecutive cardiac events, wherein N, when applied at the second time, is modified in view of the occurrence of the first time; and finding that the persistence rule is not met due to the increase in N at least once. - View Dependent Claims (8, 9, 10)
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11. A method of identifying an arrhythmia in an implantable defibrillator, the implantable defibrillator including a plurality of implantable electrodes coupled to operational circuitry for analyzing cardiac signals and generating therapy outputs, the method comprising:
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detecting events using signals captured by the electrodes; determining whether individual detected events indicate a likely arrhythmia by the use of an X-out-of-Y filter; applying therapy criteria to the X-out-of-Y filter and determining the therapy criteria are met; when the therapy criteria are met, applying persistence criteria to determine whether the therapy criteria are met for a quantity of consecutive detected events; determining the persistence criteria are met; when the persistence criteria are met, applying last event criteria to determine whether at least one most recent detected events meets treatment criteria; if the last event criteria are met, then initiating a charging sequence to prepare for therapy delivery to the patient;
orif the last event criteria are not met, waiting for another detected event and re-applying the therapy criteria, persistence criteria, and last event criteria until either; the persistence criteria or therapy criteria are no longer met;
orall of the last event criteria, persistence criteria, and therapy criteria are met simultaneously.
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Specification