System for heart rate variability analysis

• US 5,291,400 A
• Filed: 04/09/1992
• Issued: 03/01/1994
• Est. Priority Date: 04/09/1992
• Status: Expired due to Fees

• Current Assignee: Spacelabs, Inc. (OSI Systems Incorporated)
• Original Assignee: Spacelabs Medical Incorporated (OSI Systems Incorporated)
• Inventors: Gilham, Jeffrey J.
• Primary Examiner(s): McElheny, Jr., Donald E.
• Application Number:
  US07/866,806
• Time in Patent Office: 691 Days
• Field of Search: 364/413.05, 364/413.06, 128/702, 128/703, 128/704, 128/705
• US Class Current: 600/509
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/335 using integrated circuit memory devices
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

A method and system for heart variability analysis is provided. A computer system generates various statistical and spectral measurements of heart rate variability based on user-specified qualifications and displays the results. The computer system includes a statistical and spectral data component. The spectral component includes a data storage device for storing electrocardiographic data, an interval detector for determining the length of heart beat intervals in the electrocardiographic data, an instantaneous interval function data generator for generating instantaneous interval function data based on the interval data and user-specified qualifications, a filter and resampler for generating resampled data by filtering and resampling the instantaneous interval function data, a power spectral density data generator for generating spectral density data based on the resampled data and user-specified qualifications, a period spectral data generator for accumulating period and region spectral data measurements based on the generated power spectral density data, a time period, and user-specified qualifications, and a display controller for displaying period data and region data. The invention allows a user to specify minimum and maximum beat interval times, whether intervals near atrial and ventricular ectopic beats should be disregarded, the time period over which data is to be accumulated, the difference margins for beat triplets, the region of time over which data is accumulated, and whether data is to be displayed in graphical or tabular format.

Claims

1. A computer system for heart rate variability analysis of electrocardiographic data, the system comprising:

a storage device having means for storing electrocardiographic data;

an interval detector f or determining the length of heart beat intervals in the electrocardiographic data;

a minute data generator for accumulating statistical measurements based on the heart beat intervals and user-specified qualifications;

a period data generator for accumulating statistical data measurements based on the generated minute data, a time period, and user-specified qualifications;

a region data generator for accumulating statistical measurements based on the generated minute data and a region of time; and

a display controller for displaying the period data and region data on a computer display device.

2. The computer system of claim 1 wherein the user-specified qualifications include a minimum and a maximum interval time, wherein intervals with interval times less than the minimum and greater than the maximum are not used to generate the minute data.

3. The computer system of claim 1 wherein the user-specified qualifications include a number of intervals before an atrial ectopic beat, wherein the number of intervals before an atrial ectopic beat are not used to generate the minute data.

4. The computer system of claim 1 wherein the user-specified qualifications include a number of intervals after an atrial ectopic beat, wherein the number of intervals after an atrial ectopic beat are not used to generate the minute data.

5. The computer system of claim 1 wherein the user-specified qualifications include a number of intervals before a ventricular ectopic beat, wherein the number of intervals before a ventricular ectopic beat are not used to generate the minute data.

6. The computer system of claim 1 wherein the user-specified qualifications include a number of intervals after a ventricular ectopic beat, wherein the number of intervals after a ventricular ectopic beat are not used to generate the minute data.

7. The computer system of claim 1 wherein the user-specified qualifications include a minimum number of intervals per minute, wherein when the period data generator determines that a minute of electrocardiographic data has less than the minimum number of intervals, then minute data from that minute is not used to generate interval period data.

8. The computer system of claim 1 wherein the user-specified qualifications include a minimum number of triplets per minute, wherein when the period data generator determines that a minute of electrocardiographic data has less than the minimum number of triplets, then minute data from that minute is not used to generate difference period data.

9. The computer system of claim 1 wherein the user-specified qualifications include a difference margin for the difference in time of intervals that comprise a triplet, wherein when the difference exceeds the difference margin, the triplet will be used to compute %RRxx.

10. The computer system of claim 1 wherein the period data is displayed in tabular format on the computer display device in response to a user selection of tabular format and the period data is displayed in graphic format on the computer display device in response to the user selection of graphical format.

11. The computer system of claim 1 wherein the user-specified qualifications include the number of minutes of minute data to be accumulated into one time period of period data.

12. The computer system of claim 1 wherein the display controller includes means for simultaneously displaying on the computer display device generated region data and generated period data.

13. The computer system of claim 12 including:

means for receiving a user-specified region of time; and

means for updating displayed region data in response to receiving a user-specified region of time.

14. The computer system of claim 1 wherein when period data corresponds to a period within a user-specified region of time, then the period data is displayed with an indicator that the period is within the user-specified region.

15. The computer system of claim 14 wherein when period data corresponds to periods not within the user-specified region of time, then the period data is displayed with an indicator that the period is not within the user-specified region.

16. The computer system of claim 1 wherein period data that corresponds to periods not within a user-specified region of time is not displayed.

17. A computer system for heart rate variability analysis of electrocardiographic data, the system comprising:

a storage device having means for storing electrocardiographic data;

an interval detector f or determining the length of heart beat intervals in electrocardiographic data;

an instantaneous interval function generator for generating instantaneous interval f unction data based on the interval data and user-specified qualifications;

a filter and resampler for generating resampled data by filtering and resampling the instantaneous interval function data;

a power spectral density data generator for generating spectral density data based on the resampled data, a time base specifying the period over which the data is generated, and user-specified qualifications;

a period spectral data generator for accumulating period spectral data measurements and region spectral data measurements based on the generated power spectral density, a time period, and user-specified qualifications; and

a display controller for displaying the period data and region data on a computer display device.

18. The computer system of claim 17 wherein the user-specified qualifications include a minimum and a maximum interval time, wherein a first interval with an interval time that is between the minimum and maximum interval times has its interval time increased by the interval time of a second interval when the interval time of the second interval is less than the minimum or greater than the maximum interval time.

19. The computer system of claim 17 wherein the user-specified qualifications include a number of intervals before an atrial ectopic beat, wherein the number of intervals before an atrial ectopic beat are not used to generate the instantaneous interval function data.

20. The computer system of claim 17 wherein the user-specified qualifications include a number of intervals after an atrial ectopic beat, wherein the number of intervals after an atrial ectopic beat are not used to generate the instantaneous interval function data.

21. The computer system of claim 17 wherein the user-specified qualifications include a number of intervals before a ventricular ectopic beat, wherein the number of intervals before a ventricular ectopic beat are not used to generate the instantaneous interval function data.

22. The computer system of claim 17 wherein the user-specified qualifications include a number of intervals after a ventricular ectopic beat, wherein the number of intervals after a ventricular ectopic beat are not used to generate the instantaneous interval function data.

23. The computer system of claim 17 wherein the time base is a user-specified time base.

24. The computer system of claim 17 wherein the user-specified qualifications include a percent of valid data, and wherein when a time base of data has less than the percent of valid data, then the period spectral data generator excludes the power spectral density data f or that time base from the accumulation of power spectral density data for the period.

25. The computer system of claim 17 wherein the user-specified qualifications include frequency ranges, wherein the computer system accumulates total power within each frequency range.

26. The computer system of claim 17 wherein the display controller displays a graph of the period data on the computer display device.

27. The computer system of claim 17 wherein when period data corresponds to a period within a user-specified region, then the period data is displayed with an indicator that the period is within the user-specified region.

28. The computer system of claim 17 wherein the user-specified qualifications indicate that the period data is to include an accumulation of the power spectral density data for all of the electrocardiographic data.

29. The computer system of claim 17 wherein graphs of the power spectral density data for successive time periods are automatically displayed at a user-specified rate.

30. The computer system of claim 17 wherein the display controller displays total power spectral density data for a user-specified frequency range in graphical format.

31. The computer system of claim 17 wherein the display controller displays the ratio of the total power of two frequency ranges in graphical format.

32. The computer system of claim 17 wherein the display controller including means for simultaneously displaying on the computer display device generated region data and generated period data.

33. The computer system of claim 32 including:

means for receiving a user-specified region of time; and

means for updating displayed region data in response to receiving a user-specified region of time.