VCG vector loop bifurcation

• US 10,143,392 B2
• Filed: 12/12/2016
• Issued: 12/04/2018
• Est. Priority Date: 02/27/2014
• Status: Active Grant

• Current Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Original Assignee: Zoll Medical Corporation (Asahi Kasei Corporation)
• Inventors: Weng, Binwei, Herken, Ulrich, Freeman, Gary A.
• Primary Examiner(s): MALAMUD, DEBORAH LESLIE
• Application Number:
  US15/375,861
• Publication Number:
  US 20170112400A1
• Time in Patent Office: 722 Days
• CPC Class Codes: A61B 2505/01 Emergency care
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/339 Displays specially adapted therefor
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61N 1/3904 External heart defibrillators [EHD]
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

A system for determining T wave bifurcation that includes three or more ECG leads configured to receive an ECG signal and a first computing device including a processor coupled to a memory, the processor and the memory configured to perform operations including: generating at least two orthogonal ECG vectors based on the ECG signal of a patient, processing the at least two orthogonal ECG vectors to determine a loop trajectory of at least a portion of the ECG signal, identifying a trajectory bifurcation by comparing the loop trajectory to a control loop trajectory for a plurality of cardiac cycles, and determining an indicator of a cardiac event based on the trajectory bifurcation.

Claims

1. An apparatus comprising a non-volatile computer readable medium storing instructions for causing a computing system to perform operations comprising:

receiving, from two or more ECG leads, an ECG signal of a patient;

generating at least two orthogonal ECG vectors based on the ECG signal;

processing the at least two orthogonal ECG vectors to determine a vectorcardiogram loop trajectory of at least a portion of the ECG signal;

identifying a trajectory bifurcation by comparing the vectorcardiogram loop trajectory to a control vectorcardiogram loop trajectory for at least three consecutive cardiac cycles of a plurality of cardiac cycles;

determining a variation of the trajectory bifurcation over time, the determination based on an analysis of the trajectory bifurcation of the at least three consecutive cardiac cycles;

determining an indicator of a cardiac event based on the variation of the trajectory bifurcation; and

delivering a treatment to the patient based on the determined indicator of the cardiac event.

2. The apparatus of claim 1, wherein the cardiac event comprises an impending acute degeneration of a patient'"'"'s medical condition.

3. The apparatus of claim 2, wherein the impending acute degeneration is one of a cardiac arrest and a traumatic arrest.

4. The apparatus of claim 1, wherein the apparatus is a defibrillator.

5. The apparatus of claim 4, the operations comprising delivering the treatment by the defibrillator to the patient based on the indicator of the cardiac event.

6. The apparatus of claim 1, wherein the two or more ECG leads are included within a wearable defibrillator worn by the patient, and the apparatus is configured to be in communication with the wearable defibrillator.

7. The apparatus of claim 6, wherein the vectorcardiogram loop trajectory is a test vectorcardiogram loop trajectory that comprises a first plurality vectorcardiogram loop trajectories obtained during a first time period and the control vectorcardiogram loop trajectory comprises a second plurality of vectorcardiogram loop trajectories obtained during a second time period that is prior to the first time period.

8. The apparatus of claim 7, wherein the first time period comprises a time period in present or recent past and the second time period comprises a time period in a more distant past.

9. The apparatus of claim 7, wherein the first time period comprises a time period within 60 minutes of a present time and the second time period comprises a time period within 72 hours of the present time.

10. The apparatus of claim 7, wherein the first time period and the second time period are separated by at least 5 minutes.

11. The apparatus of claim 7, wherein generating the at least two orthogonal ECG vectors based on the ECG signal comprises generating the at least two orthogonal ECG vectors during a second period of time, the second period of time occurring subsequent to the first time period.

12. The apparatus of claim 6, wherein identifying the trajectory bifurcation further comprises measuring a degree of trajectory bifurcation between the vectorcardiogram loop trajectory and the control vectorcardiogram loop trajectory.

13. The apparatus of claim 6, wherein identifying the trajectory bifurcation further comprises identifying landmarks in the vectorcardiogram loop trajectory and in the control vectorcardiogram loop trajectory.

14. The apparatus of claim 6, wherein identifying the trajectory bifurcation further comprises determining a measure of a shape uncertainty of the vectorcardiogram loop trajectory and the control vectorcardiogram loop trajectory.

15. The apparatus of claim 14, wherein determining the measure of the shape uncertainty is based on a statistical analysis of an uncertainty boundary of the vectorcardiogram loop trajectory and the control vectorcardiogram loop trajectory.

16. The apparatus of claim 6, wherein the cardiac event comprises an impending acute degeneration of a patient'"'"'s medical condition.

17. The apparatus of claim 16, wherein the impending acute degeneration is one of a cardiac arrest and a traumatic arrest.

18. The apparatus of claim 6, wherein the instructions further comprise providing an alert regarding the cardiac event.

19. The apparatus of claim 6, wherein the instructions further comprise delivering the treatment to the patient based on the indicator of the cardiac event.

20. The apparatus of claim 1, wherein the indicator is determined at different time periods.

21. The apparatus of claim 20, wherein the different time periods vary between minutes and days.

22. The apparatus of claim 21, wherein the different time periods comprise at least one of 10 minutes, 1 hour, 2 hours, 4 hours, 8 hours, 12 hours, 24 hours, 48 hours, and 72 hours.

23. The apparatus of claim 1, wherein the portion of the ECG signal comprises at least one of a T wave, a P wave and a S wave.

24. The apparatus of claim 1, the operations comprising displaying the indicator of the cardiac event.

25. The apparatus of claim 1, wherein the vectorcardiogram loop trajectory is a test vectorcardiogram loop trajectory that comprises a first plurality vectorcardiogram loop trajectories obtained during a first time period and the control vectorcardiogram loop trajectory comprises a second plurality of vectorcardiogram loop trajectories obtained during a second time period that is prior to the first time period.

26. The apparatus of claim 25, wherein the first time period comprises a time period in present or recent past and the second time period comprises a time period in a more distant past.

27. The apparatus of claim 25, wherein the first time period comprises a time period within 60 minutes of a present time and the second time period comprises a time period within 72 hours of the present time.

28. The apparatus of claim 25, wherein the first time period and the second time period are separated by at least 5 minutes.

29. The apparatus of claim 1, wherein identifying the trajectory bifurcation further comprises measuring a degree of the trajectory bifurcation between the vectorcardiogram loop trajectory and the control vectorcardiogram loop trajectory.

30. The apparatus of claim 29, wherein measuring the degree of the trajectory bifurcation is based on a statistical analysis.

31. The apparatus of claim 30, wherein the statistical analysis is a non-Gaussian statistical analysis.

32. The apparatus of claim 1, wherein identifying the trajectory bifurcation further comprises identifying landmarks in the vectorcardiogram loop trajectory and in the control vectorcardiogram loop trajectory.

33. The apparatus of claim 1, wherein identifying the trajectory bifurcation further comprises determining a measure of a shape uncertainty of the vectorcardiogram loop trajectory and the control vectorcardiogram loop trajectory.

34. The apparatus of claim 33, wherein determining the measure of the shape uncertainty is based on a statistical analysis of an uncertainty boundary of the vectorcardiogram loop trajectory and the control vectorcardiogram loop trajectory.

35. The apparatus of claim 1, wherein the computing system comprises a mobile computing device.

36. The apparatus of claim 1, wherein the control vectorcardiogram loop trajectory is generated based on a plurality of predetermined vectorcardiogram loop trajectories derived from one or more of a P, T, and QRS segments of the ECG signal of the patient during a first period of time.

37. A computer-implemented method executed by one or more processors, the method comprising:

receiving, from two or more ECG leads, an ECG signal of a patient;

generating at least two orthogonal ECG vectors based on the ECG signal;

processing the at least two orthogonal ECG vectors to determine a vectorcardiogram loop trajectory of at least a portion of the ECG signal;

identifying a trajectory bifurcation by comparing the vectorcardiogram loop trajectory to a control vectorcardiogram loop trajectory for at least three consecutive cardiac cycles of a plurality of cardiac cycles;

determining a variation of the trajectory bifurcation over time, the determination based on an analysis of the trajectory bifurcation of the at least three consecutive cardiac cycles;

determining an indicator of a cardiac event based on the variation of the trajectory bifurcation; and

delivering a treatment to the patient based on the determined indicator of the cardiac event.

38. The computer-implemented method of claim 37, wherein processing the at least two orthogonal ECG vectors to determine the vectorcardiogram loop trajectory comprises:

detecting an onset of the portion of the ECG signal and an end of the portion of the ECG signal;

isolating the portion of the ECG signal based on detecting the onset of the portion of the ECG signal and the end of the portion of the ECG signal; and

generating a vector vectorcardiogram loop based of the portion of the ECG signal.

39. The computer-implemented method of claim 37, wherein identifying the trajectory bifurcation comprises:

calculating an area of the vectorcardiogram loop trajectory; and

subtracting the area of the vectorcardiogram loop trajectory from an area of the control vectorcardiogram loop trajectory.

40. The computer-implemented method of claim 39, wherein identifying the trajectory bifurcation further comprises:

comparing the trajectory bifurcation of the at least three consecutive cardiac cycles of the plurality of cardiac cycles;

determining a trend of the trajectory bifurcation; and

based on the trend, defining an episodic trajectory bifurcation.

41. The computer-implemented method of claim 37, further comprising displaying the indicator of the cardiac event.

42. The computer-implemented method of claim 37, wherein the two or more ECG leads are included within a wearable defibrillator worn by the patient.