Signal Analysis of Cardiac and Other Patient Medical Signals

• US 20090112106A1
• Filed: 10/20/2008
• Published: 04/30/2009
• Est. Priority Date: 10/24/2007
• Status: Active Grant

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens Medical Solutions USA Incorporated (Siemens AG)
• Inventors: Zhang, Hongxuan
• Granted Patent: US 8,396,541 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle

Abstract

A system and method provide detecting and monitoring cardiac electrophysiological changes by determining differences between a reference signal representing a heartbeat signal and an analysis signal representing another heartbeat signal. A set of signal data consisting of a number of heartbeat signals is acquired as a function of time. Individual heartbeat signals within the set of acquired signals are identified, an individual signal comprising data values representing a plurality of sample points during a single heartbeat. One of the identified individual signals or a derived signal representing an average of a subset of the identified individual signals is selected as an analysis signal. A reference signal is identified. The sample points of the reference signal are aligned with the sample points of the analysis signal. A single value representative of mutual correspondence between the sample points of the reference signal and the corresponding sample points of the analysis signal is calculated. Data indicating a calculated value is communicated to a destination for viewing by a user

Claims

1. A method of analyzing cardiac electrophysiological signals, the method comprising the activities of:

acquiring a set of signal data representing a plurality of cardiac electrophysiological signals as a function of time;

identifying individual signals within the set of acquired signal data, an individual signal comprising data values representing a plurality of sample points from a single heartbeat;

selecting one of the identified individual signals or a derived signal representing an average of a subset of the identified individual signals as an analysis signal;

identifying data representing a reference signal, the reference signal comprising data values representing a plurality of sample points;

aligning the sample points of the reference signal with the sample points of the analysis signal;

calculating a single value representative of differences between the sample points of the reference signal and the corresponding sample points of the analysis signal; and

communicating data indicating a calculated value to a destination for viewing by a user.

2. The method of claim 1, wherein the activity of calculating the value representative of differences between the reference signal and the analysis signal is a calculation of mutual correspondence, performed according to:

3. The method of claim 1, wherein the activity of calculating the value representative of differences between the reference signal and the analysis signal is a calculation of mutual correspondence, performed according to:

4. The method of claim 1, wherein the activity of calculating the value representative of differences between the reference signal and the analysis signal further includes the activities of:

transforming the signal data of the reference signal from data as a function of time to data as a function of frequency;

transforming the signal data of the analysis signal from data as a function of time to data as a function of frequency;

calculating the mutual correspondence between the reference signal and the analysis signal using the data as a function of frequency; and

calculating a time-frequency mutual correspondence value between the reference signal and the analysis signal, performed according to;

5. The method of claim 1, wherein the activity of calculating the value representative of the mutual correspondence of the reference signal and the analysis signal further includes the activities of:

transforming the signal data of the reference signal from data as a function of time to signal data as a function of other variables;

transforming the signal data of the analysis signals from data as a function of time to signal data as a function of other variables;

calculating the mutual correspondence between the reference signal and the analysis signal for each set of transformed signal data; and

calculating a value representative of a multi-dimensional mutual correspondence of the reference signal and the analysis signal, performed according to;

6. The method of claim 5, wherein the set of signal data acquired represents electrocardiogram signals for a patient and the value representative of the mutual correspondence of the reference signal and the analysis signal is provided to assist in the monitoring or diagnosis of cardiac electrophysiological changes.

7. The method of claim 5, wherein the activity of calculating the value representative of the mutual correspondence of the reference signal and the analysis signal is performed only over a selected portion of an electrocardiogram signal.

8. The method of claim 1, wherein the reference signal is one of:

(a) acquired from or (b) derived by an averaging calculation from one of (c) a set of signals from a patient or (d) a repository of cardiac electrophysiological signal data.

9. The method of claim 8, wherein the reference signal is derived from one of:

(a) current electrocardiogram signals for a patient, (b) previous electrocardiogram signals for the patient, (c) previous electrocardiogram signals for patients whose physical characteristics match the patient.

11. A system for analyzing cardiac electrophysiological signals, the system comprising:

an acquisition processor for acquiring a set of signal data representing a plurality of cardiac electrophysiological signals as a function of time;

a signal processor coupled to said acquisition processor for

identifying individual signals within the set of acquired signals, each individual signal comprising data values on a plurality of sample points from a single heartbeat;

selecting one of said identified individual signals or an average of a subset of said identified individual signals to obtain an analysis signal,

identifying data representing a reference signal, the reference signal comprising data values on a plurality of sample points, and

aligning the sample points of the reference signal with the sample points of the analysis signal;

a calculation processor coupled to said signal processor for calculating a value representative of differences between the sample points of the reference signal and the corresponding sample points of the analysis signal; and

an output processor coupled to said calculation processor for outputting said calculated value to a user.

12. The system of claim 11, wherein said signal data acquired by said acquisition processor is electrocardiogram signals.

13. The system of claim 12, wherein said signal processor averages a plurality of electrocardiogram signals to remove noise and artifacts from the acquired signals.

14. The system of claim 11, wherein said calculation processor operates to calculate said value representative of differences between the reference signal and the analysis signal by calculating mutual correspondence, according to:

15. The system of claim 11, wherein said calculation processor operates to calculate said value representative of differences between the reference signal and the analysis signal by calculating mutual correspondence, according to:

16. The system of claim 11, further comprising

a memory coupled to said acquisition processor and said signal processor for storing said acquired signal data and, wherein

said signal processor transforms a stored set of signal data as a function of time into a set of signal data as a function of frequency and stores said set of transformed signal data in said memory.

17. The system of claim 15, wherein said calculation processor

calculates the mutual correspondence between the reference signal and the analysis signal using the signal data as a function of frequency;

and

calculates a time-frequency mutual correspondence between the reference signal and the analysis signal, performed according to;

18. The system of claim 11, further comprising

a memory coupled to said acquisition processor and said signal processor for storing said acquired signal data and, wherein

said signal processor transforms a stored set of signal data as a function of time into sets of signal data as functions of other variables and transforms the signal data of the analysis signals as a function of time into sets of signal data as functions of other variables;

and

said calculation processor calculates the mutual correspondence A_i between the reference signal and the analysis signal for each set of signal data and transformed signal data, to produce a value representing a multi-dimensional mutual correspondence between the reference signal and the analysis signal, according to;