Asystole and complete heart block detection
In one example, an apparatus of a wearable cardioverter defibrillator (WCD) system comprises a support structure wearable by a patient, a plurality of electrocardiogram (ECG) electrodes to obtain an ECG signal, a processor to receive and analyze the ECG signal of the patient, wherein the processor is configured to monitor four or more channels of the ECG signal, a high voltage subsystem coupled with defibrillation electrodes configured to be coupled with patient, wherein the processor is configured to cause the high voltage subsystem to apply a therapeutic shock to the patient through the defibrillation electrodes in response to a shockable event detected by the processor from the ECG signal. The processor measures a peak-to-peak amplitude of QRS complexes of the ECG signal, and detects asystole in the patient when the peak-to-peak amplitude of one or more QRS complexes is less than an asystole threshold. Other examples and related methods are disclosed herein.
1. An apparatus of a wearable cardioverter defibrillator (WCD) system, comprising:
a support structure wearable by a patient;
a plurality of electrocardiogram (ECG) electrodes capable of being applied to the skin of the patient to obtain an ECG signal;
a processor to receive and analyze the ECG signal of the patient, wherein the processor is configured to monitor four or more channels of the ECG signal; and
a high voltage subsystem coupled with defibrillation electrodes configured to be coupled with patient, wherein the processor is configured to cause the high voltage subsystem to apply a therapeutic shock to the patient through the defibrillation electrodes in response to a shockable event detected by the processor from the ECG signal;
wherein the processor is further configured to:
measure a peak-to-peak amplitude of QRS complexes of the ECG signal; and
detecting asystole in the patient when the peak-to-peak amplitude of one or more QRS complexes is less than an asystole threshold; and
wherein a unique asystole threshold is set for each of the four or more channels.
2. The apparatus of claim 1 , wherein the unique asystole threshold of at least one of the four or more channels is set to a fixed value.
3. The apparatus of claim 2 , wherein the fixed value ranges from about 100 microvolts to about 200 microvolts.
4. The apparatus of claim 1 , wherein the unique asystole threshold of at least one of the four or more channels is set to a percentage of a peak-to-peak amplitude of a normal QRS complex of the patient.
5. The apparatus of claim 1 , wherein the processor is further configured to:
detect respiration of the patient; and
determine that the patient is in asystole when the peak-to-peak amplitude of one or more of the QRS complexes is lower than a unique conditional threshold and higher than an absolute threshold for at least one of the four or more channels, and when no patient respiration is detected.
6. The apparatus of claim 1 , wherein asystole is detected only when the peak-to-peak amplitudes of QRS complexes in all four channels falls below the unique asystole threshold for each of the four or more channels.
7. An apparatus of a wearable cardioverter defibrillator (WCD) system, comprising:
a support structure wearable by a patient;
a plurality of electrocardiogram (ECG) electrodes capable of being applied to the skin of the patient to obtain an ECG signal;
a processor to receive and analyze the ECG signal of the patient, wherein the processor is configured to monitor four or more channels of the ECG signal; and
a high voltage subsystem coupled with defibrillation electrodes configured to be coupled with patient, wherein the processor is configured to cause the high voltage subsystem to apply a therapeutic shock to the patient through the defibrillation electrodes in response to a shockable event detected by the processor from the ECG signal;
wherein the processor is further configured to:
measure a peak-to-peak amplitude of QRS complexes of the ECG signal;
detect respiration of the patient; and
detect asystole in the patient when the peak-to-peak amplitude of one or more of the QRS complexes is lower than a conditional asystole threshold and higher than an absolute asystole threshold, and when no patient respiration is detected.
8. The apparatus of claim 7 , wherein the conditional asystole threshold is set to a fixed value.
9. The apparatus of claim 8 , wherein the fixed value ranges from about 100 microvolts to about 200 microvolts.
10. The apparatus of claim 7 , wherein the conditional asystole threshold is set to a percentage of a peak-to-peak amplitude of a normal QRS complex of the patient.
11. The apparatus of claim 7 , wherein a unique conditional asystole threshold is set for each of the four or more channels.
12. The apparatus of claim 7 , wherein asystole is detected only when the peak-to-peak amplitudes of QRS complexes in each of the four or more of the channels falls below the conditional asystole threshold.
13. An apparatus of a wearable cardioverter defibrillator (WCD) system, comprising:
a support structure wearable by a patient;
a plurality of electrocardiogram (ECG) electrodes capable of being applied to the skin of the patient to obtain an ECG signal;
a processor to receive and analyze the ECG signal of the patient, wherein the processor is configured to monitor four or more channels of the ECG signal; and
a high voltage subsystem coupled with defibrillation electrodes configured to be coupled with patient, wherein the processor is configured to cause the high voltage subsystem to apply a therapeutic shock to the patient through the defibrillation electrodes in response to a shockable event detected by the processor from the ECG signal;
wherein the processor is further configured to:
measure a peak-to-peak amplitude of QRS complexes of the ECG signal; and
detecting asystole in the patient when the peak-to-peak amplitude of one or more QRS complexes is less than an asystole threshold; and
wherein asystole is detected only when the peak-to-peak amplitudes of QRS complexes in each of the four or more channels falls below the asystole threshold.
14. The apparatus of claim 13 , wherein the asystole threshold is set to a fixed value.
15. The apparatus of claim 14 , wherein the fixed value ranges from about 100 microvolts to about 200 microvolts.
16. The apparatus of claim 13 , wherein the asystole threshold is set to a percentage of a peak-to-peak amplitude of a normal QRS complex of the patient.
17. The apparatus of claim 13 , wherein a unique asystole threshold is set for each of the four or more channels.
18. The apparatus of claim 13 , wherein the processor is further configured to:
detect respiration of the patient; and
determine that the patient is in asystole when the peak-to-peak amplitude of one or more of the QRS complexes is lower than a conditional systole threshold and higher than an absolute asystole threshold, and when no patient respiration is detected.