Wearable cardioverter defibrillator having reduced noise prompts

Patent metadata

Field	Value
Publication number	US-2018184933-A1
Application number	US-201815861463-A
Country	US
Kind code	A1
Filing date	Jan 3, 2018
Priority date	Jan 5, 2017
Publication date	Jul 5, 2018
Grant date	—

Abstract

A wearable cardioverter defibrillator (WCD) including a support structure configured to be worn by an ambulatory patient, an energy storage module configured to store an electrical charge, a discharge circuit coupled to the energy storage module, electrodes configured to render an electrocardiogram (ECG) signal of the patient while the patient is wearing the support structure, a user interface configured to output an alarm in response to a noise alarm signal, and a processor. The processor is configured to receive the ECG signal, determine whether noise is present on the ECG signal, determine from the ECG signal whether a shock criterion is met, and cause the user interface to generate the noise alarm signal when the noise is present on the ECG signal and the shock criterion is met and not generate the noise alarm signal when noise is present on the ECG signal and the shock criterion is not met.

First claim

We claim:

1 . A wearable cardioverter defibrillator (WCD), comprising:
a support structure configured to be worn by an ambulatory patient; an energy storage module configured to store an electrical charge; a discharge circuit coupled to the energy storage module; electrodes configured to render an electrocardiogram (ECG) signal of the patient while the patient is wearing the support structure; a user interface configured to output an alarm in response to a noise alarm signal; and a processor configured to:
receive the ECG signal,
determine whether noise is present on the ECG signal,
determine from the ECG signal whether a shock criterion is met, and
cause the user interface to generate the noise alarm signal when the noise is present on the ECG signal and the shock criterion is met and not generate the noise alarm signal when noise is present on the ECG signal and the shock criterion is not met.

2 . The WCD of claim 1 , wherein the processor is further configured to:
receive an additional ECG signal for a predetermined time after the shock criterion is met; determine whether noise is present on the additional ECG signal; and when the noise is determined to be present on the additional ECG signal, generate the noise alarm signal.

3 . The WCD of claim 2 , wherein the predetermined amount of time is between five seconds and fifteen minutes.

4 . The WCD of claim 1 , wherein the user interface is further configured to receive an input from a user, and wherein the processor is further configured to control the discharge circuit to discharge a stored charge if the input from the user input is not received within a predetermined amount of time after the noise alarm signal is generated.

5 . The WCD of claim 1 , wherein the processor is further configured to detect QRS complexes in the ECG signal and determine noise is present on the ECG signal when a detected QRS complex is greater than a threshold.

6 . The WCD of claim 5 , wherein the threshold is between 2-20 mV.

7 . The WCD of claim 1 , wherein the processor is further configured to detect QRS complexes in the ECG signal and determine noise is present on the ECG signal when an amplitude of an unfiltered baseline shift in the vicinity of a detected QRS complex is larger than a threshold.

8 . The WCD of claim 7 , wherein the threshold is between 2-20 mV.

9 . The WCD of claim 1 , wherein the processor is further configured to detect QRS complexes in the ECG signal and determine noise is present on the ECG signal when a number of baseline crossings near a detected QRS complex is greater than a threshold.

10 . The WCD of claim 1 , wherein the processor is further configured to detect QRS complexes in the ECG signal and determine noise is present on the ECG signal when a pulse width of a detected QRS complex is less than a threshold.

11 . The WCD of claim 1 , further comprising a physical sensor configured to output a signal and wherein the processor is further configured to determine noise is present on the ECG signal when the signal from the physical sensor and the ECG signal are correlated.

12 . The WCD of claim 1 , further comprising a physical sensor configured to output a signal and wherein the processor is further configured to:
detect a high rate of change on the signal; detect a QRS complex in the ECG signal; determine whether the high rate of change is coincident with the QRS complex; and determine noise is present on the ECG signal when the high rate of change is coincident with the QRS complex.

13 . The WCD of claim 1 , wherein the alarm is an audible alarm.

14 . A wearable cardioverter defibrillator (WCD), comprising:
a support structure configured to be worn by an ambulatory patient; an energy storage module configured to store an electrical charge; a discharge circuit coupled to the energy storage module; electrodes configured to render an electrocardiogram (ECG) signal of the patient while the patient is wearing the support structure; a user interface configured to output an alarm in response to a noise alarm signal; and a processor configured to:
receive the ECG signal,
determine whether high frequency noise or high amplitude noise is present on the ECG signal,
when the noise is high frequency noise, determine from the ECG signal whether a shock criterion is met, cause the user interface to generate the noise alarm signal when the high frequency noise is present on the ECG signal and the shock criterion is met, and cause the user interface to not generate the noise alarm signal when the high frequency noise is present on the ECG signal and the shock criterion is not met, and
when the noise is high amplitude noise, cause the user interface to generate the noise alarm signal when the high amplitude noise is present for a predetermined amount of time.

15 . The WCD of claim 14 , wherein the processor is further configured to suspend analysis of the ECG signal to determine whether a shock criterion is met when the noise is high amplitude noise.

16 . The WCD of claim 15 , wherein the processor is further configured to parse the ECG signal into a plurality of segments and suspend analysis of the ECG signal when at least at least a predetermined ratio of received segments of the ECG signal have high amplitude noise.

17 . The WCD of claim 16 , wherein the processor is further configured to suspend analysis of the ECG signal until a predetermined ratio of ECG segments are determined to not have high amplitude noise or the predetermined time has elapsed and the noise alarm signal is generated.

18 . The WCD of claim 14 , wherein the predetermined amount of time is between one and fifteen minutes.

19 . The WCD of claim 14 , wherein the processor is further configured to:
receive an additional ECG signal for a predetermined time after the shock criterion is met; determine whether high frequency noise is present on the additional ECG signal; and when high frequency noise is determined to be present on the additional ECG signal, generate the noise alarm signal.

20 . The WCD of claim 19 , wherein the predetermined amount of time is between five seconds and fifteen minutes.

21 . The WCD of claim 14 , further comprising a user input configured to receive an input from a user, and wherein the processor is further configured to control the discharge circuit to discharge a stored electrical charge if the input from the user input is not received within a predetermined amount of time after the noise alarm signal is generated.

22 . The WCD of claim 14 , wherein the processor is further configured to detect QRS complexes in the ECG signal and determine high amplitude noise is present on the ECG signal when a detected QRS complex is greater than a threshold.

23 . The WCD of claim 22 , wherein the threshold is between 2-20 mV.

24 . The WCD of claim 14 , wherein the processor is further configured to detect QRS complexes in the ECG signal and determine high amplitude noise is present on the ECG signal when an amplitude of an unfiltered baseline shift in the vicinity of a detected QRS complex is larger than a threshold.

25 . The WCD of claim 24 , wherein the threshold is between 2-20 mV.

26 . The WCD of claim 14 , wherein the processor is further configured to detect QRS complexes in the ECG signal and determine high frequency noise is present on the ECG signal when a number of

Assignees

• West Affum Holdings Corp

Inventors

• Sullivan Joseph L
• Kim Jaeho

Classifications

• A61B5/346

  Analysis of electrocardiograms · CPC title

• A61B5/7217 Primary

  of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker · CPC title

• A61B5/04018 Primary

  Human Necessities · mapped topic

• A61B5/6805

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

• A61N1/3904

  External heart defibrillators [EHD] · CPC title