Method And System For Cardiac Signal Decomposition

• US 20080097537A1
• Filed: 10/13/2005
• Published: 04/24/2008
• Est. Priority Date: 10/13/2004
• Status: Active Grant

• Current Assignee: Sigmed Incorporated
• Original Assignee: Sigmed Incorporated
• Inventors: Jung, Tzyy-Ping, Duann, Jeng-Ren
• Granted Patent: US 7,853,317 B2
• Time in Patent Office: Days
• US Class Current: 607/14
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle

Abstract

A method and system decomposes a cardiac signal, such as an electrocardiogram (ECG) signal, into components. The components are then usable to assist in the detection of an abnormal heart condition. More particularly, a single lead sensor is used to generate a single lead cardiac signal. The cardiac signal is segmented into a set of cycle segments according to detected heart waveforms. The cycle segments are aligned and used to generate a set of cross-sectional signals. The cross-sectional signals are aligned and presented as inputs to a signal separation process, which separates the cardiac signal into a set of components. The components may be grouped according to predefined criteria. The components or groups may be analyzed or displayed to assist in the detection of an abnormal cardiac signal, which may be indicative of an abnormal heart condition. In one example, the signal separation process is a non-orthogonal transformation method such as independent component analysis (ICA).

Claims

1. A method of decomposing an electrocardiogram (ECG) signal, the method comprising:

receiving an ECG signal;

segmenting the received ECG signal into a set of cycle segments;

aligning the set of cycle segments;

generating a set of cross-sectional signals from the cycle segments;

separating, using the signal separation process, the set of cross-sectional signals into a set of statistically substantially independent components; and

detecting, using the set of components, an abnormal cardiac signal.

2. The method of claim 1, further comprising the steps of:

selecting a plurality of the independent components that match a predefined criteria; and

arranging the selected independent components into a component group.

3. The method of claim 2, wherein the detecting step comprises detecting the abnormal cardiac signal in the component group.

4. The method of claim 2, wherein the selecting step has predefined criteria that comprises a frequency criteria, and one of the component groups is arranged to have independent components matching the frequency criteria.

5. The method of claim 2, further comprising displaying at least one of the arranged component groups and a name identifying the predefined criteria.

6. The method of claim 2, further comprising displaying the component group.

7. The method of claim 1, further comprising the steps of:

displaying at least some of the independent components to an operator;

receiving from the operator instructions to select a plurality of the independent components; and

arranging the selected independent components into a component group.

8. The method of claim 1, wherein segmenting the received ECG signal comprises isolating the received ECG signal into a set of QRS complex wave cycle segments.

9. The method of claim 1, wherein aligning the cycle segments comprises detecting an R-wave peak point of each of the cycle segments.

10. The method of claim 1, wherein aligning the cycle segments comprises detecting a P-wave peak point of each of the cycle segments.

11. The method of claim 1, wherein aligning the cycle segments comprises detecting a Q-wave peak point of each of the cycle segments.

12. The method of claim 1, wherein aligning the cycle segments comprises detecting a R-wave peak point of each of the cycle segments and calculating time intervals between adjacent R-wave peak points.

13. The method of claim 1, wherein segmenting the received ECG signal comprises arranging each cycle segment to have one and only one heart waveform cycle.

14. The method of claim 1, wherein segmenting the received ECG signal comprises arranging each cycle segment to have a plurality of heart waveform cycles.

15. The method of claim 1, wherein separating the set of cycle segments comprises using a non-orthogonal transformation.

16. The method of claim 1, wherein separating the set of cycle segments comprises using an independent component analysis process.

17. The method of claim 1, wherein the receiving step comprises receiving the ECG signal as a one channel ECG signal from a single lead sensor.

18. The method of claim 1, wherein the receiving step comprises receiving the ECG signal from one channel from a multi-lead sensor.

19. A system for decomposing a channel of ECG signals, the system comprising:

a signal port configured to receive an ECG signal from a single-lead ECG sensor;

a signal receiver connected to the signal port;

a cycle detection module connected to the signal receiver and configured to segment the ECG signal and generate a set of input signals;

a component separation module connected to the cycle detection module and adapted to separate the set of input signals into a set of independent components; and

an output device coupled to the component separation module and operated responsive to the set of independent components.

20. The system according to claim 19, further comprising an analysis module configured to detect an abnormal cardiac signal in the set of independent components.

21. The system according to claim 19, further comprising a component group module adapted to select and organize the independent components into component groups.

22. The system according to claim 21, further comprising an analysis module configured to detect an abnormal cardiac signal in at least one of the component groups.

23. The system according to claim 19, further comprising a memory holding predefined criteria, the predefined criteria being indicative of an abnormal cardiac signal.

24. The system according to claim 19, wherein the output device comprises a graphical display.

25. The system according to claim 19, wherein the output device comprises an alarm.

26. The system according to claim 19, wherein the output device comprises a pace-maker circuit to stimulate a heart muscle.

27. The system of claim 19, wherein the cycle detection module is adapted to detect R-waves in ECG signal and to segment the ECG signal into a set of QRS complex cycles based on the detected R-waves.

28. The system of claim 19, wherein the component separation module is adapted to separate the set of input signals using a non-orthogonal transformation.

29. The system of claim 19, wherein the component separation module is adapted to separate the set of input signals using an independent component analysis method.

30. A method of detecting an abnormal cardiac signal in an electrocardiogram (ECG) signal, the method comprising:

receiving a one channel continuous ECG signal;

detecting heartbeat cycles in the ECG signal;

arranging the heartbeat cycles into a set of cycle segments;

aligning the set of cycle segments;

generating a set of cross-sectional signals;

separating, using the signal separation process, the set of cross-sectional signals into a set of statistically substantially independent components;

grouping the independent components into component groups according to a predefined criteria; and

detecting, using the component groups, the abnormal cardiac signal.

31. The method according to claim 30, further including displaying one or more component groups on a display device.

32. The method according to claim 30, further including activating an alarm responsive to detecting the abnormal cardiac signal.

33. The method according to claim 30, further including activating pacemaker circuitry responsive to detecting the abnormal cardiac signal.

34. The method according to claim 30, wherein the separating step comprises using a non-orthogonal transformation.

35. The method according to claim 30, wherein the separating step comprises using an independent component analysis process.

36. The method according to claim 30, wherein the grouping step comprises generating a group having independent components matching predefined criteria for one of the abnormalities in the group consisting of atrial fibrillation, Wolff-Parkinson-White (WPW) syndrome, ventricular hypertrophy, ventricular tachycardia, sinus arrhythmia, wandering atrial pacemaker, multifocal atrial tachycardia, atrial flutter, agonal rhythm, torsades de pointes, first-degree AV block, wenchebach, type II second-degree AV block, ST segment augmentation, Q-wave abnormalities, and myocardial infarction.

37. The method of claim 30, wherein the receiving step comprises receiving the ECG signal as a one channel ECG signal from a single lead sensor.

38. The method of claim 30, wherein the receiving step comprises receiving the ECG signal from one channel from a multi-lead sensor.