Wearable cardioverter defibrillator components discarding ecg signals prior to making shock/no shock determination

Abstract

Components of wearable cardiac defibrillator (WCD) systems, software, and methods are provided. A WCD system includes a support structure that a patient can wear and electrodes that can capture at least two of the patient's ECG signals. A component includes an energy storage module that can store an electrical charge, a discharge circuit, and a processor that can make a shock/no shock determination, and cause the discharge circuit to discharge the stored charge, if the determination is to shock. In some embodiments, the processor discards at least one of the ECG signals prior to making the shock/no shock determination. The determination can be made from the remaining one or more ECG signals. In some embodiments, the processor makes an aggregate shock/no shock determination from two or more of the ECG signals.

1 . A component of a wearable cardiac defibrillation system, the system including a support structure configured to be worn by a patient and electrodes configured to capture at least three ECG signals of the patient and transport electrical charge, the component comprising:
 an energy storage module configured to be coupled to the support structure and to store an electrical charge;   a discharge circuit coupled to the energy storage module; and   a processor configured to:
 decide whether at least one of the at least three ECG signals meets a reliability criterion and, if not, to discard it, 
 make a shock/no shock determination from one of the ECG signals that is not the discarded ECG signal, and 
 cause, if the determination is to shock, the discharge circuit to discharge the electrical charge through at least two of the electrodes so as to defibrillate the patient. 
   
     
     
         2 . The component of  claim 1 , in which
 the reliability criterion is that the ECG signal has a reliability value that is higher than a threshold.   
     
     
         3 . The component of  claim 1 , in which
 the reliability criterion is that the ECG signal has a reliability value that is higher than the reliability value of another of the ECG signals.   
     
     
         4 . The component of  claim 1 , in which
 all the ECG signals are discarded except one.   
     
     
         5 . The component of  claim 4 , in which
 the reliability criterion is that the ECG signal that is not discarded is the one that has a higher reliability value than the other ECG signals.   
     
     
         6 . The component of  claim 4 , in which
 the shock/no shock determination is not made if the non-discarded ECG signal has a reliability value that is less than a threshold.   
     
     
         7 . The component of  claim 1 , in which
 the component or the wearable cardiac defibrillation system further includes an implement configured to detect an ECG common voltage signal, and   the reliability criterion for a certain ECG signal is derived from a mathematical correlation between the ECG common voltage signal and the certain ECG signal.   
     
     
         8 . The component of  claim 7 , in which
 the mathematical correlation includes a cross-correlation, and   the ECG common voltage signal and the certain ECG signal are simplified before the cross-correlation.   
     
     
         9 . The component of  claim 1 , in which
 an impedance signal of the patient is also captured, and   the reliability criterion for a certain ECG signal is derived from a mathematical correlation between the impedance signal and the certain ECG signal.   
     
     
         10 . The component of  claim 9 , in which
 the mathematical correlation includes a cross-correlation, and   the impedance signal and the certain ECG signal are simplified before the cross-correlation.   
     
     
         11 . The component of  claim 9 , in which
 the component or the wearable cardiac defibrillation system further includes an accelerometer configured to generate an acceleration signal, and   the reliability criterion for a certain ECG signal is derived from a mathematical correlation between the acceleration signal and the certain ECG signal.   
     
     
         12 . The component of  claim 11 , in which
 the mathematical correlation includes a cross-correlation, and   the acceleration signal and the certain ECG signal are simplified before the cross-correlation.   
     
     
         13 . The component of  claim 1 , in which
 the decision is made from a patient heart rate detected in the ECG signal.   
     
     
         14 . The component of  claim 1 , in which
 a mathematical correlation is taken between two of the ECG signals.   
     
     
         15 . The component of  claim 1 , in which
 the reliability criterion is not met if two others of the ECG signals have an aspect similar to each other.   
     
     
         16 . A component of a wearable cardiac defibrillation system, the system including a support structure configured to be worn by a patient and electrodes configured to capture at least two ECG signals of the patient and transport electrical charge, the component comprising:
 an energy storage module configured to be coupled to the support structure and to store an electrical charge;   a discharge circuit coupled to the energy storage module; and   a processor configured to:
 decide whether at least one of the ECG signals meets a reliability criterion from a measured amplitude of at least one of the ECG signals and, if not, to discard it, 
 make a shock/no shock determination from one of the ECG signals that is not the discarded ECG signal, and 
 cause, if the determination is to shock, the discharge circuit to discharge the electrical charge through at least two of the electrodes so as to defibrillate the patient. 
   
     
     
         17 . The component of  claim 16 , in which
 the reliability criterion is met depending on how well the measured amplitude matches a reference amplitude.   
     
     
         18 . The component of  claim 17 , in which
 the reference amplitude has been measured in advance for the patient.   
     
     
         19 . The component of  claim 16 , in which
 the reliability criterion is met depending on how large is a ratio of a peak value to a median value of the ECG signal.   
     
     
         20 . A non-transitory computer-readable storage medium storing one or more programs which, when executed by at least one processor of a wearable cardiac defibrillation system, the system including a support structure configured to be worn by a patient, electrodes configured to capture at least three ECG signals of the patient and transport electrical charge, an energy storage module configured to be coupled to the support structure and to store an electrical charge, and a discharge circuit coupled to the energy storage module, they result in:
 deciding whether at least one of the at least three ECG signals meets a reliability criterion and, if not, discarding it;   making a shock/no shock determination from one of the ECG signals that is not the discarded ECG signal, and   causing, if the determination is to shock, the discharge circuit to discharge the electrical charge through at least two of the electrodes so as to defibrillate the patient.   
     
     
         21 - 34 . (canceled) 
     
     
         35 . A non-transitory computer-readable storage medium storing one or more programs which, when executed by at least one processor of a wearable cardiac defibrillation system, the system including a support structure configured to be worn by a patient, electrodes configured to capture at least two ECG signals of the patient and transport electrical charge, an energy storage module configured to be coupled to the support structure and to store an electrical charge, and a discharge circuit coupled to the energy storage module, they result in:
 deciding whether at least one of the ECG signals meets a reliability criterion from a measured amplitude of the at least one of the ECG signals and, if not, discarding it;   making a shock/no shock determination from one of the ECG signals that is not the discarded ECG signal, and   causing, if the determination is to shock, the discharge circuit to discharge the electrical charge through at least two of the electrodes so as to defibrillate the patient.   
     
     
         36 - 38 . (canceled) 
     
     
         39 . A method for a component of a wearable cardiac defibrillation system, the system including a support structure configured to be worn by a patient, electrodes configured to capture at least three ECG signals of the patient and transport electrical charge, an energy storage module configured to be coupled to the support structure and to store an electrical charge, and a discharge circuit coupled to the energy storage module, the method comprising:
 deciding whether at least one of the at least three ECG signals meets a reliability criterion and, if not, discarding it;   making a shock/no shock determination from one of the ECG signals that is not the discarded ECG signal, and   causing, if the determination is to shock, the discharge circuit to discharge the electrical charge through at least two of the electrodes so as to defibrillate the patient.   
     
     
         40 - 53 . (canceled) 
     
     
         54 . A method for a component of a wearable cardiac defibrillation system, the system including a support structure configured to be worn by a patient, electrodes configured to capture at least two ECG signals of the patient and transport electrical charge, an energy storage module configured to be coupled to the support structure and to store an electrical charge, and a discharge circuit coupled to the energy storage module, the method comprising:
 deciding whether at least one of the ECG signals meets a reliability criterion from a measured amplitude of the at least one of the ECG signals and, if not, discarding it;   making a shock/no shock determination from one of the ECG signals that is not the discarded ECG signal, and   causing, if the determination is to shock, the discharge circuit to discharge the electrical charge through at least two of the electrodes so as to defibrillate the patient.   
     
     
         55 - 93 . (canceled)