Cardiac Arrhythmias Analysis of Electrophysiological Signals Based on Symbolic Dynamics

• US 20080281216A1
• Filed: 12/14/2007
• Published: 11/13/2008
• Est. Priority Date: 05/10/2007
• Status: Active Grant

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Inventors: Zhang, Hongxuan, Koertge, Detlef W.
• Granted Patent: US 8,086,303 B2
• Time in Patent Office: Days
• US Class Current: 600/515
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• 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

Abstract

The disclosed method analyzes cardiac electrophysiological signals, including ECG and internal cardiac electrograms, based on multi-level symbolic complexity calculation and multi-dimensional mapping. The results may be used to objectively identify cardiac disorders, differentiate cardiac arrhythmias, characterize pathological severities, and predict life-threatening events. Multi-level symbolization and calculation of the electrophysiological signal is used provide better reliability and analysis resolution for identifying and characterizing cardiac disorders. Adaptive analysis of the cardiac signal complexity enables calculation efficiency and reliability with high SNR, and with low calculation volume and power consumption. One dimension (time or frequency domain) and multi-dimension symbolic analysis is used to provide more information of cardiac pathology and high risk rhythm transition to doctors.

Claims

1. A method for predicting cardiac arrhythmia, comprising

monitoring patient data elements, the data elements comprising a data stream;

performing symbolization of the data stream;

performing a symbolic complexity calculation on the symbolized data;

comparing information obtained from the symbolic complexity calculation to a predetermined threshold; and

providing information to a user if the information obtained from the symbolic complexity calculation exceeds the predetermined threshold.

2. The method of claim 1, wherein the step of performing symbolization of the data stream comprises a multi-level complexity calculation.

3. The method of claim 2, wherein the step of performing symbolic complexity calculation on the symbolized data comprises a multi-level complexity calculation.

4. The method of claim 3, wherein the patient data elements comprise patient cardiac signals.

5. The method of claim 4, wherein the step of providing information to a user further comprises:

providing a graphical display of frequency domain complexity vs. time domain complexity, the graphical display comprising a predetermined visible normal region associated with normal cardiac signals and a predetermined visible severe region associated with cardiac signals indicative of arrhythmia; and

mapping the complexity calculation on the graphical display to provide a visual indication to a user that the cardiac signals are;

(a) within the normal region, (b) are approaching the severe region, or (c) are within the severe region.

6. The method of claim 5, wherein the complexity calculation is mapped on the graphical display over time to provide a visible trending of the cardiac signals, the method further comprising providing a risk threshold that identifies to a user when the cardiac signals are trending to the severe region.

7. The method of claim 4, wherein the step of providing information to a user comprises providing an audible or visual alarm to the user if the information obtained from the symbolic complexity calculation exceeds the predetermined threshold.

8. A system for predicting cardiac arrhythmia, comprising

means for monitoring patient data elements, the data elements comprising a data stream;

means for performing symbolization of the data stream;

means for performing a symbolic complexity calculation on the symbolized data;

means for comparing information obtained from the symbolic complexity calculation to a predetermined threshold; and

means for providing information to a user if the information obtained from the symbolic complexity calculation exceeds the predetermined threshold.

9. The system of claim 8, wherein the means for performing symbolization of the data stream is capable of performing a multi-level complexity calculation.

10. The system of claim 9, wherein the means for performing symbolic complexity calculation on the symbolized data comprises is capable of performing a multi-level complexity calculation.

11. The system of claim 10, wherein the patient data elements comprise patient cardiac signals.

12. The system of claim 11, wherein the means for providing information to a user further comprises:

means for providing a graphical display of frequency domain complexity vs. time domain complexity, the graphical display comprising a predetermined visible normal region associated with normal cardiac signals and a predetermined visible severe region associated with cardiac signals indicative of arrhythmia; and

means for mapping the complexity calculation on the graphical display to provide a visual indication to a user that the cardiac signals are;

(a) within the normal region, (b) are approaching the severe region, or (c) are within the severe region.

13. The system of claim 12, wherein the complexity calculation is mapped on the graphical display over time to provide a visible trending of the cardiac signals, the system further comprising means for providing a risk threshold that identifies to a user when the cardiac signals are trending to the severe region.

14. The system of claim 13, wherein the means for providing information to a user is capable of providing an audible or visual alarm to the user if the information obtained from the symbolic complexity calculation exceeds the predetermined threshold.

15. A machine readable storage device tangibly embodying a series of instructions executable by the machine to perform a series of steps, the steps comprising:

monitoring patient data elements, the data elements comprising a data stream;

performing symbolization of the data stream;

performing a symbolic complexity calculation on the symbolized data;

comparing information obtained from the symbolic complexity calculation to a predetermined threshold; and

providing information to a user if the information obtained from the symbolic complexity calculation exceeds the predetermined threshold.

16. The machine readable storage device of claim 15, wherein the step of performing symbolization of the data stream comprises a multi-level complexity calculation.

17. The machine readable storage device of claim 16, wherein the step of performing symbolic complexity calculation on the symbolized data comprises a multi-level complexity calculation.

18. The machine readable storage device of claim 17, wherein the patient data elements comprise patient cardiac signals.

19. The machine readable storage device of claim 18, wherein the step of providing information to a user further comprises:

providing a graphical display of frequency domain complexity vs. time domain complexity, the graphical display comprising a predetermined visible normal region associated with normal cardiac signals and a predetermined visible severe region associated with cardiac signals indicative of arrhythmia; and

mapping the complexity calculation on the graphical display to provide a visual indication to a user that the cardiac signals are;

(a) within the normal region, (b) are approaching the severe region, or (c) are within the severe region.

20. The machine readable storage device of claim 19, wherein the complexity calculation is mapped on the graphical display over time to provide a visible trending of the cardiac signals, the method further comprising providing a risk threshold that identifies to a user when the cardiac signals are trending to the severe region.