System and a method for analyzing ECG curvature

• US 7,477,936 B2
• Filed: 12/20/2004
• Issued: 01/13/2009
• Est. Priority Date: 12/19/2003
• Status: Active Grant

• Current Assignee: Aalborg Universitet
• Original Assignee: Aalborg Universitet
• Inventors: Toft, Egon, Struijk, Johannes Jan, Kanters, Jørgen Kim, Andersen, Mads Peter, Graff, Claus, Hardahl, Thomas Bork
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Wu; Eugene T
• Application Number:
  US11/014,915
• Publication Number:
  US 20050177049A1
• Time in Patent Office: 1,485 Days
• Field of Search: None
• US Class Current: 600/509
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle

Abstract

A system or a method for analysing ECG curvature wherein at least one among a number of different parameters is isolated, for indicating symptoms of diseases having influence on the ECG curvature. The system and method provides for objective, fast and effective indication of a number of symptoms derivable from an ECG curve which may be indicative of one or more diseases. This can be achieved when a first number of selected parameters are combined in at least a first mathematical analysis, where the result of the analysis can be represented as a point in a coordinate system comprising at least two axes where the system can compare the actual placement in the coordinate system with a number of reference parameters stored in the system for indicating diseases having influence on the ECG curvature.

Claims

1. Method for analysing ECG curvature, which curvature contains a number of parameters, wherein the method for analysing the ECG curvature incorporates the steps of:

a) receiving ECG curvature from a source,

b) indicating a number of different parameters contained in the received ECG curvature,

c) storing the parameters in storage means,

d) select disease specific parameters in the storage means

e) combine selected parameters in mathematical analysing means

f) represent the result of the mathematical analysis as a point in a coordinate system, comprising at least two axes,

g) compare the actual placement in the coordinate system with a number of reference parameters stored in a memory,

h) indicating diseases having influence on the ECG curvature.

2. Method according to claim 1, wherein the method repeats the analysing process for further selected parameters for indicating further diseases.

3. Method according to claim 2, wherein the method divides parameters into at least three groups, which groups contains parameters selected from the group consisting of symmetry, flatness, duration, and combinations thereof.

4. A system for analyzing ECG curvatures and isolating at least one among a number of different parameters, each of which relates to a section of ECG curvature, comprising an ECG source, an input device connected to the ECG source, indicator reflecting different parameters of a received ECG curvature and indicating potential symptoms relative to diseases responsive to the different parameters and based on the diseases influencing the ECG curvature, a computer readable medium encoded with a program for carrying out a first mathematical analysis for combining a first number of selected parameters, outputting a result of the first mathematical analysis as a representative point in a coordinate system, the coordinate system comprising at least two axes, comparing actual placement in the coordinate system with a number of reference parameters stored in the system, and indicating symptoms of diseases having influence on the ECG curvature.

5. System of claim 4, further comprising repeating the analyzing process in the system for further selected parameters and indicating further possible diseases or symptoms.

6. System of claim 5, wherein the parameters are divided into at least two main groups in the system.

7. System of claim 6, wherein the parameters are selected from the group consisting of symmetry, flatness, duration, and combinations thereof.

8. System of claim 7, wherein the group of symmetry comprises parameters selected from the group consisting of the following parameters and combinations thereof:

S1 Skewness evaluated from Tstart to Tend,

S2 Skewness evaluated from Tstart to Tend with Ttop as mean,

S3 Skewness evaluated in a symmetric interval, 10% of the Tstart-Tend interval surrounding Ttop with Ttop as mean

S4 Skewness evaluated i a symmetric interval, 20% of the Tstart-Tend interval surrounding Ttop wit Ttop as mean,

S5 Ratio of the time interval from Tstart to Ttop and the time interval from Ttop to Tend,

S6 Ratio of the average slope from Tstart to Ttop and from Ttop to Tend, wherein the group of flatness is selected form the group consisting of the following parameters and combinations thereof;

F1 Kurtosis evaluated from Tstart to Tend,

F2 F1 normalized by the absolute Rtop-Qnadir value,

F3 Kurtosis evaluated from Tstart to Tend with Ttop as mean,

F4 F3 normalized by absolute Rtop-Qnadir value,

F5 Kurtosis evaluated in a symmetric interval, 10% of the Tstart-Tend interval surrounding Ttop with Ttop as mean,

F6 F5 normalized by absolute Rtop-Qnadir value,

F7 Kurtosis evaluated in a symmetric interval, 20% of the Tstart-Tend interval surrounding Ttop with Ttop as mean,

F8 Kurtosis normalized by the value of Rtop with Ttop as mean,

F9 Ratio of the total area under the T-wave from Tstart to Ttop and the corresponding time interval,

F10 F9 normalized by absolute Rtop-Qnadir value,

F11 Ratio of the total area under the T-wave from Ttop to Tend and the corresponding time interval,

F12 F11 normalized by absolute Rtop-Qnadir value

F13 Ratio of the total area under the T-wave from Tstart to Tend and the corresponding time interval,

F14 F13 normalized by absolute Rtop-Qnadir value,

F15 Ratio of the height of Rtop and the width of the Tstart-Tend interval, wherein the group of duration is selected from the group consisting of the following parameters and combinations thereof;

QTc The Q-T interval normalized by the square root of the R-R interval according to Bazett'"'"'s formula,

D2 Time interval from Tstart to Tend,

D3 Time interval from Tstart to Ttop,

D4 Time interval from Ttop to Tend.

9. System according to claim 6, further comprising combining parameters from different groups.

10. System according to claim 7, further comprising a computer readable medium encoded with a program for carrying out system analysis of the QT interval of the ECG curvature for indicating Long QT syndrome.

11. A system for analysing ECG curvature wherein at least one among a number of different parameters is isolated, which system has input means connected to an ECG source and a processor configured to indicate and/or isolate parameters, combine them in a mathematical analysis, and compare the results of the mathematical analysis with reference parameters, where the different parameters of a received ECG curvature are indicated and/or isolated for indicating possible symptoms which relates to or are indications of certain diseases, where said diseases are known to influence the ECG curvature, and that a first number of selected parameters, are combined in at least a first mathematical analysis, where the result of the analysis is represented as a point in a coordinate system, comprising at least two axes, where the system compares the actual placement in the coordinate system with a number of reference parameters stored in the system, for indicating symptoms of diseases having influence on the ECG curvature, wherein the mathematical analysis is repeated in the system for further selected parameters for indicating further possible diseases or symptoms, wherein the parameters are divided into at least two main groups in the system, which groups contains parameters of symmetry, flatness and duration.

12. System according to claim 11, wherein the group of symmetry contains at least following parameters:

S1 Skewness evaluated from Tstart to Tend,

S2 Skewness evaluated from Tstart to Tend with Ttop as mean,

S3 Skewness evaluated in a symmetric interval, 10% of the Tstart-Tend interval surrounding Ttop with Ttop as mean

S4 Skewness evaluated i a symmetric interval, 20% of the Tstart-Tend interval surrounding Ttop wit Ttop as mean,

S5 Ratio of the time interval from Tstart to Ttop and the time interval from Ttop to Tend,

S6 Ratio of the average slope from Tstart to Ttop and from Ttop to Tend, where the group of flatness contains at least the following parameters;

F1 Kurtosis evaluated from Tstart to Tend,

F2 F1 normalized by the absolute Rtop-Qnadir value,

F3 Kurtosis evaluated from Tstart to Tend with Ttop as mean,

F4 F3 normalized by absolute Rtop-Qnadir value,

F5 Kurtosis evaluated in a symmetric interval, 10% of the Tstart-Tend interval surrounding Ttop with Ttop as mean,

F6 F5 normalized by absolute Rtop-Qnadir value,

F7 Kurtosis evaluated in a symmetric interval, 20% of the Tstart-Tend interval surrounding Ttop with Ttop as mean,

F8 Kurtosis normalized by the value of Rtop with Ttop as mean,

F9 Ratio of the total area under the T-wave from Tstart to Ttop and the corresponding time interval,

F10 F9 normalized by absolute Rtop-Qnadir value,

F11 Ratio of the total area under the T-wave from Ttop to Tend and the corresponding time interval,

F12 F11 normalized by absolute Rtop-Qnadir value

F13 Ratio of the total area under the T-wave from Tstart to Tend and the corresponding time interval,

F14 F13 normalized by absolute Rtop-Qnadir value,

F15 Ratio of the height of Rtop and the width of the Tstart-Tend interval, where the group of duration contains at least the following parameters;

QTc The Q-T interval normalized by the square root of the R-R interval according to Bazett'"'"'s formula,

D2 Time interval from Tstart to Tend,

D3 Time interval from Tstart to Ttop,

D4 Time interval from Ttop to Tend.

13. System according to claim 11, wherein the system is combining parameters from different groups.

14. System according to claim 12, wherein the system analyses the QT interval of the ECG curvature for indicating Long QT syndrome.

15. A system for analysing ECG curvature wherein at least one among a number of different parameters, each of which relates to a section of ECG curvature, is isolated, which system has input means connected to an ECG source and a processor configured to indicate and/or isolate parameters, combine them in a mathematical analysis, and compare the results of the mathematical analysis with reference parameters, where the different parameters of a received ECG curvature are indicated and/or isolated for indicating possible symptoms which relates to or are indications of certain diseases, where said diseases are known to influence the ECG curvature, and that a first number of selected parameters, are combined in at least a first mathematical analysis, where the result of the analysis is represented as a point in a coordinate system, comprising at least two axes, where the system compares the actual placement in the coordinate system with a number of reference parameters stored in the system, for indicating symptoms of diseases having influence on the ECG curvature.

16. System according to claim 15, wherein the mathematical analysis is repeated in the system for further selected parameters for indicating further possible diseases or symptoms.