SYSTEM, SOFTWARE, AND METHOD FOR DETECTION OF SLEEP-DISORDERED BREATHING USING AN ELTROCARDIOGRAM

• US 20080319326A1
• Filed: 02/13/2008
• Published: 12/25/2008
• Est. Priority Date: 08/23/2004
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: University of Texas At Arlington (University of Texas System)
• Inventors: Behbehani, Khosrow, Burk, John R., Vijendra, Sridhar, Lucas, Edgar A.
• Granted Patent: US 7,801,593 B2
• Time in Patent Office: Days
• US Class Current: 600/484
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/7257 using Fourier transforms

Abstract

A system to form and store an electrocardiogram (ECG) signal derived from a cardiac electrical signal that includes an apparatus having a pair of the electrodes to connect to a patient to detect the cardiac electrical signal. A signal sampler samples the cardiac electrical signal to form the ECG signal. A data storage device stores the ECG signal. A computer communicates with the data storage device to retrieve the ECG signal for analysis by software stored in the memory of the computer. The software analyzes a morphology of the amplitude of a plurality of R-wave peaks contained within the ECG signal and/or analyzes a morphology of the area of a plurality of QRS complex pulses contained within the ECG signal.

Claims

1. A method for detecting sleep-disordered breathing, the method comprising:

detecting a plurality of QRS complex pulses within an electrocardiogram signal;

determining a plurality of QRS complex pulse area values for a preselected time band, variations in the area of each of the plurality of QRS complex pulse areas defining QRS complex pulse area morphology for the plurality of QRS complex pulses;

analyzing the QRS complex pulse area morphology for the plurality of QRS complex pulses; and

detecting sleep disordered breathing, when existing, responsive to the analysis responsive to the analysis of the change in value between the area of each of the plurality of QRS complex pulse areas.

2. A method as defined in claim 1, further comprising the step of:

forming a QRS complex pulse area value sampled series by interpolating between QRS complex pulse area values of an electrocardiogram signal to form a QRS complex pulse area value trend and by sampling the formed QRS complex pulse area value trend; and

wherein

the step of analyzing the QRS complex pulse area morphology of the plurality of QRS complex pulses includes the steps of;

determining a power spectral density of the QRS complex pulse area value sampled series, and

determining a power level in a preselected frequency band of the power spectral density.

3. A method as defined in claim 2, further comprising the step of comparing the determined power level to a predetermined threshold level to determine if the predetermined threshold level is exceeded.

4. A method as defined in claim 2, wherein the preselected frequency band is a first frequency band having a first power level, the method further comprising performing at least one of the following steps:

comparing the first power level to a first predetermined threshold level to determine if the first predetermined threshold level is exceeded, the preselected frequency band approximately between 0.0 to 0.1 Hz; and

comparing a second power level of a second frequency band to a second predetermined threshold level to determine if the second power level fails to exceed the second predetermined threshold level, the second preselected frequency band approximately between 0.2 to 0.3 Hz.

5. A method as defined in claim 1, further comprising the steps of:

dividing the electrocardiogram signal into a first plurality of epochs;

forming an QRS complex pulse area value sampled series for each epoch in a subset of the first plurality of epochs defining a second plurality of epochs by interpolating between QRS complex pulse area values of each epoch in the second plurality of epochs to form an QRS complex pulse area value trend for each epoch in the second plurality of epochs and by sampling the formed QRS complex pulse area value trend for each of the second plurality of epochs; and

determining a power spectral density of the QRS complex pulse area value sampled series for each of the second plurality of epochs.

6. A method as defined in claim 5, further comprising the steps of:

determining a power level in a preselected frequency band of the power spectral density for each of the second plurality of epochs;

comparing the determined power level for each of the second plurality of epochs to a predetermined threshold level to determine if the predetermined threshold level is exceeded; and

determining the existence of sleep-disordered breathing when a preselected percentage of second plurality of epochs exceed the predetermined threshold level.

7. A method as defined in claim 2, wherein the preselected time band is less than 100 milliseconds wide.

8. A method as defined in claim 1, further comprising the steps of:

determining a power level in a preselected frequency band of the power spectral density for each of a plurality of epochs;

comparing the determined power level for each of the plurality of epochs to a predetermined threshold level to determine if the predetermined threshold level is exceeded; and

determining the existence of sleep-disordered breathing when a preselected percentage of the plurality of epochs fails to exceed the predetermined threshold level.

9. A system to detect sleep-disordered breathing, the system comprising:

an apparatus to form and store an electrocardiogram signal from a cardiac electrical signal, the apparatus including;

at least one electrocardiogram lead having a pair of the electrodes adapted to connect to a selected portion of a patient to detect the cardiac electrical signal, the signal having a plurality of QRS complex pulses,

a data sampler electrically connected to the at least one electrocardiogram lead to form the electrocardiogram signal by sampling the detected cardiac electrical signal,

a data storage device for storing the electrocardiogram signal;

a computer having a processor and a memory associated therewith, the processor positioned to communicate with the data storage device and the memory; and

QRS complex pulse area morphology analyzing software stored in the memory of the computer for analyzing a morphology of an area value for a plurality of QRS complex pulses in an electrocardiogram signal, the QRS complex pulse area morphology analyzing software including instructions that when executed by the computer, cause the computer to perform the operations of;

analyzing variations in an area of each of the plurality of QRS complex pulse areas defining QRS complex pulse area morphology for the plurality of QRS complex pulses, and

detecting sleep disordered breathing, when existing, responsive to the analysis of the change in value between the area of each of the plurality of QRS complex pulse areas.

10. A system as defined in claim 9, wherein the QRS complex pulse area morphology analyzing software includes:

a QRS complex pulse area value determiner to determine the QRS complex pulse area values of the plurality of QRS complex pulses for a plurality of electrocardiogram signal epochs, each QRS complex pulse area value determined for a preselected time band less than 100 milliseconds wide and coincident with a position of corresponding R-wave peaks in the electrocardiogram signal; and

a QRS complex pulse area value morphology analyzer, responsive to the QRS complex pulse area value determiner, to detect sleep-disordered breathing from morphology of the area value for the plurality of QRS complex pulses in the electrocardiogram signal.

11. A system as defined in claim 10, wherein the QRS complex pulse area value morphology analyzer includes:

a QRS complex pulse area value time series generator, responsive to the QRS complex pulse area value determiner, to interpolate between QRS complex pulse area values of each of the plurality of epochs to form an QRS complex pulse area value trend and to uniformly sample the QRS complex pulse area value trend to form an evenly sampled series defining a QRS complex pulse area value series for each of the plurality of epochs; and

a power spectral density determiner, responsive to the QRS complex pulse area value time series generator, to determine a power spectral density for the QRS complex pulse area value series for each of the plurality of epochs.

12. A computer readable medium that is readable by a computer facilitating detecting sleep disordered breathing in a patient, the computer readable medium comprising a set of instructions that, when executed by the computer, cause the computer to perform the following operations:

detecting a plurality of QRS complex pulses within an electrocardiogram signal;

determining a plurality of QRS complex pulse area values for a corresponding plurality of QRS complex pulses within an electrocardiogram signal, variations in the area of each of the plurality of QRS complex pulse areas defining QRS complex pulse area morphology for the plurality of QRS complex pulses;

analyzing the change in value between the area of each of the plurality of QRS complex pulse areas; and

detecting sleep disordered breathing, when existing, responsive to the analysis responsive to the analysis of the change in value between the area of each of the plurality of QRS complex pulse areas.

13. A computer readable medium as defined in claim 12,

wherein the operations further comprise forming a QRS complex pulse area value sampled series by interpolating between QRS complex pulse area values of an electrocardiogram signal to form a QRS complex pulse area value trend and by sampling the formed QRS complex pulse area value trend;

and

wherein the operation of analyzing the change in value between the area of each of the plurality of QRS complex pulse areas includes the operations of;

determining a power spectral density of the QRS complex pulse area value sampled series, and

determining a power level in a preselected frequency band of the power spectral density.

14. A computer readable medium as defined in claim 13, wherein the operations further comprise comparing the determined power level to a predetermined threshold level to determine if the predetermined threshold level is exceeded.

15. A computer readable medium as defined in claim 13, wherein the operations further comprise comparing a power level the preselected frequency band to a predetermined threshold level to determine if the predetermined threshold level is exceeded, the preselected frequency band approximately between 0.0 to 0.1 Hz.

16. A computer readable medium as defined in claim 13, wherein the operations further comprise comparing a power level of the preselected band to a predetermined threshold level to determine if the power level fails to exceed the predetermined threshold level, the preselected frequency band approximately between 0.2 to 0.3 Hz.

17. A computer readable medium as defined in claim 12, wherein the operations further comprise:

dividing the electrocardiogram signal into a first plurality of epochs;

forming an QRS complex pulse area value sampled series for each epoch in a subset of the first plurality of epochs defining a second plurality of epochs by interpolating between QRS complex pulse area values of each epoch in the second plurality of epochs to form an QRS complex pulse area value trend for each epoch in the second plurality of epochs and by sampling the formed QRS complex pulse area value trend for each of the second plurality of epochs; and

determining a power spectral density of the QRS complex pulse area value sampled series for each of the second plurality of epochs.

18. A computer readable medium as defined in claim 17, wherein the operations further comprise:

determining a power level in a preselected frequency band of the power spectral density for each of the second plurality of epochs;

comparing the determined power level for each of the second plurality of epochs to a predetermined threshold level to determine if the predetermined threshold level is exceeded; and

determining the existence of sleep-disordered breathing when a preselected percentage of second plurality of epochs exceed the predetermined threshold level.

19. A computer readable medium as defined in claim 13, wherein the preselected time band is less than 100 milliseconds wide.

20. A computer readable medium as defined in claim 13, wherein the operation of determining a power level in a preselected frequency band of the power spectral density comprises determining a power level in a preselected frequency band of the power spectral density for each of a plurality of epochs, and where in the operations further comprise:

comparing the determined power level for each of the plurality of epochs to a predetermined threshold level to determine if the predetermined threshold level is exceeded; and

determining the existence of sleep-disordered breathing when a preselected percentage of the plurality of epochs fails to exceed the predetermined threshold level.