Wearable cardioverter defibrillator (wcd) with low false alarm rate

Patent metadata

Field	Value
Publication number	US-2022032077-A1
Application number	US-202117503065-A
Country	US
Kind code	A1
Filing date	Oct 15, 2021
Priority date	Feb 14, 2018
Publication date	Feb 3, 2022
Grant date	—

Abstract

A wearable cardioverter defibrillator (WCD) comprises a plurality of electrocardiography (ECG) electrodes, a right-leg drive (RLD) electrode, and a plurality of defibrillator electrodes to contact the patient's skin when the WCD is delivering therapy to the patient, a preamplifier coupled to the ECG electrodes and the RLD electrode to obtain ECG data from the patient as one or more ECG vectors, a processor to receive ECG data from the preamplifier and an abort signal from a user interface, an isolation barrier to isolate the preamplifier from the processor, and a high voltage subsystem to provide a defibrillation voltage to the patient through the defibrillator electrodes in response to a shock signal received from the processor. A shock is provided when an abort signal is not received within a predetermined time period of a shock criterion being met. Less than one false alarm occurs every ten patient-days.

First claim

1 - 12 . (canceled)

13 . A method to determine whether a defibrillation shock should be applied with a wearable cardioverter defibrillator (WCD), the method comprising:
receiving electrocardiography (ECG) data from a patient using the WCD with a preamplifier coupled to one or more ECG electrodes and a right-leg drive (RLD) electrode coupled to the patient's skin to obtain ECG data from the patient as one or more ECG vectors; receiving ECG data from the preamplifier with a processor; determining with the processor if a shock criterion is met based on a combination of heart rate data and a width of one or more QRS pulses identified in the ECG data; signaling the patient that the defibrillation shock is about to be applied; and applying the defibrillation shock to the patient unless a stop shock signal is caused by the patient within a predetermined period of time after signaling the patient; wherein the processor is to determine when a shock criterion is met based on the ECG data from the preamplifier, and to provide the defibrillation shock in the event the shock criterion is met and the stop shock signal is not received with a predetermined time period of the shock criterion being met; wherein the predetermined time period comprises a confirmation period when the shock criterion is met and the shock criterion is for ventricular fibrillation (VF); and wherein the predetermined time period comprises an extended confirmation period different from the confirmation period when the ECG data indicates the shock criterion is met and the shock criterion is for ventricular tachycardia (VT), the shock criterion for VT being different than the shock criterion for VF.

14 . The method of claim 13 , further comprising identifying one or more QRS pulses in the ECG data using a matched filter in the processor.

15 . The method of claim 13 , further comprising processing the ECG data with the processor in segments of ECG data, wherein the shock criterion is met when a string of a predetermined number of segments indicate a shock decision should be made.

16 . The method of claim 13 , further comprising incurring less than one false alarm indicating the shock criterion has been met every ten patient-days.

17 . A wearable cardioverter defibrillator (WCD), comprising:
a plurality of electrocardiography (ECG) electrodes and a plurality of therapy electrodes, the plurality of ECG electrodes and the plurality of therapy electrodes arranged to operatively contact a patient's skin when the WCD is operably attached to the patient; an amplifier coupled to the plurality of ECG electrodes to obtain multi-vector ECG data from the patient; an energy storage device configured to store an electrical charge; a high voltage subsystem coupled to the energy storage device and the plurality of therapy electrodes; and a processor coupled to the amplifier, the high voltage subsystem, and a user interface, wherein the processor is configured to:
issue an alarm if a shock criterion is met, wherein the alarm is issued with a false alarm rate of less than one false alarm in ten patient days, and
cause the high voltage subsystem to discharge the stored electrical charge from the energy storage device to the patient in response to the patient failing to respond to the alarm via the user interface within a predetermined time.

18 . The WCD of claim 17 , further comprising a right-leg drive (RLD) electrode coupled to the amplifier to provide a common mode reference for the multi-vector ECG data.

19 . The WCD of claim 17 , further comprising an isolation barrier to isolate the amplifier from the processor, wherein the amplifier is configured to transmit a digitized version of the multi-vector ECG data across the isolation barrier to the processor.

20 . The WCD of claim 17 , wherein the processor is configured to determine QRS width, heart rate, or QRS organization, or a combination thereof, from the multi-vector ECG data.

21 . A wearable cardioverter defibrillator (WCD), comprising:
a plurality of data electrodes and a plurality of defibrillator electrodes to contact a patient's skin when the WCD is delivering therapy to the patient; a user interface; a preamplifier coupled to the plurality of data electrodes to obtain patient data from the patient as one or more vectors; a processor to receive the patient data from the preamplifier and an abort signal from the user interface; and a high voltage subsystem to provide a defibrillation voltage to the patient through the plurality of defibrillator electrodes in response to a shock signal received from the processor; wherein the processor is to determine when a shock criterion is met based on the patient data from the preamplifier, and to provide the shock signal in the event the shock criterion is met and the abort signal is not received within a predetermined time period of the shock criterion being met; wherein the predetermined time period comprises a confirmation period when the shock criterion is met and the shock criterion is for ventricular fibrillation (VF), and wherein the predetermined time period comprises an extended confirmation period different from the confirmation period when the patient data indicates the shock criterion is met and the shock criterion is for ventricular tachycardia (VT), the shock criterion for VT being different than the shock criterion for VF.

22 . The WCD of claim 21 , wherein the processor is to determine QRS width data and heart rate data from the ECG data, and to determine when the shock criterion is met based on the QRS width data and the heart rate data.

23 . The WCD of claim 21 , wherein the one or more vectors comprises four vectors.

24 . The WCD of claim 21 , wherein the processor is to monitor the one or more vectors, and is configured to determine when the shock criterion is met when one or more of the vectors is noisy or when one or more of the plurality of data electrodes is in a lead-off condition.

25 . The WCD of claim 21 , wherein the preamplifier is configured to receive the patient data as differential signals using a voltage of one of the plurality of data electrodes as a common mode signal or a common mode potential.

26 . The WCD of claim 21 , wherein the preamplifier has a dynamic range at an input that is an order of magnitude or greater than a magnitude of the patient data.

27 . The WCD of claim 21 , wherein the patient data received by the processor from the preamplifier is processed using one or more digital filters including a matched filter to determine QRS width data and/or heart rate data.

28 . The WCD of claim 21 , wherein one or more of the plurality of data electrodes comprises a dry electrode to directly contact the patient's skin without using a gel or an adhesive.

29 . The WCD of claim 21 , wherein one or more of the plurality of data electrodes comprises a silver disk, a silver plated copper disk, or a resistive electrode, or a combination thereof.

30 . The WCD of claim 21 , wherein the processor is to process the patient data received from the preamplifier in segments of patient data, wherein the shock criterion is met when a string of a predetermined number of segments indicate a shock decision should be made.

31 . The WCD of claim 21 , wherein the WCD incurs less than one false alarm every ten patient-days indicating the shock criterion has been met every ten patient-days, wherein a false alarm is due to an issue with contact quality of one or more of the plurality of data electrodes with the patient's ski

Assignees

• West Affum Holdings Corp

Inventors

• Sullivan Joseph L
• Finch David P
• Medema Douglas K
• Buchanan Robert R
• Kotlarchik Garrett M
• Kim Jaeho
• Cowan Kenneth F

Classifications

• A61B5/6805

  Vests, e.g. shirts or gowns · CPC title

• A61B5/363

  Detecting tachycardia or bradycardia · CPC title

• A61B5/282

  Holders for multiple electrodes (for introduction into the body A61B5/287) · CPC title

• A61N1/3993

  User interfaces for automatic external defibrillators · CPC title

• A61B5/7203

  for noise prevention, reduction or removal · CPC title