Detection of abnormal and induction of normal heart rate variability

• US 5,718,235 A
• Filed: 07/30/1996
• Issued: 02/17/1998
• Est. Priority Date: 10/06/1992
• Status: Expired due to Term

• Current Assignee: GW Scientific Incorporated
• Original Assignee: GW Scientific Incorporated
• Inventors: Golosarsky, Boris, Wood, Nicholas
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US08/689,144
• Time in Patent Office: 567 Days
• Field of Search: 128/696, 128/697, 128/702, 128/704, 128/705, 128/708, 128/903, 128/904, 607/14, 607/17, 607/27
• US Class Current: 600/515
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/36592 controlled by the heart rate variability
• CPC Class Codes: A61N 1/3904 External heart defibrillators [EHD]

Abstract

The duration of Time Intervals, preferably 101, in an electrocardiogram, or pulses are recorded. The Mode, Mo!, or the duration most often recorded, the Median, M!, of all durations recorded, the Amplitude of the Mode, AMo!, expressed as a percentage of the most frequently recorded Modes, and the difference in duration between the longest and the shortest duration recorded, Delta X, DX!, are determined and consolidated into one or more Cluster Modes, CMo!, comprised of three Modes each, establishes a user'"'"'s baseline. If any of the 9 formulas derived from these functions differs by a predetermined percentage and time duration from the user'"'"'s baseline, then the user'"'"'s stress has reached an ALARM level. The apparatus make take the form of a chest strap on which are mounted electrocardiogram electrodes, which transmits Time Intervals to a wrist watch like device where the calculations are performed and the results displayed. If an ALARM is detected, the cellular telephone component is activated to transmit the user'"'"'s distressed state to a care provider. The apparatus may also take the form of a wrist mounted pulse transducer in lieu of the chest mounted electrodes. The apparatus may also take the form of a cardioverter defibrillator or pacemaker. If an over stressed state is detected, activate natural pacing of the user'"'"'s heart by using either the user'"'"'s own prerecorded natural heart rhythm variability or the natural heart rhythm variability of an individual matched to the user as to age, sex and physical condition.

Claims

1. A method of detecting abnormal heart rate variability comprising:

A) first recording a first subject'"'"'s RR or SOS intervals over substantially no less than 50 to substantially no more than 300 heart beat segments occurring with normal heart rate variability;

B) characterizing the sharpness of histograms of said segments comprising the numbers of each of the RR intervals recorded versus each particular RR interval as a function of the Mode of each of said segments;

C) second recording a second subject'"'"'s RR or SOS intervals over substantially no less than 50 to substantially no more than 300 heart beat segments;

D) characterizing the sharpness of the histograms of said second subject'"'"'s RR interval variations as a function of the Mode of each of said segments; and

E) indicating when the sharpness of the histograms of said second subject deviates from predetermined limits derived from the histograms of said first subject.

2. The method defined in claim 1 wherein said sharpness is characterized by the Amplitude of the Mode (AMo) occurring in said segments.

3. The method defined in claim 2 wherein said sharpness is also characterized by a number proportional to the ratio of the Amplitude of the mode (AMo) expressed as a percentage to the difference between substantially the largest and substantially the smallest RR interval in a segment (Δ

X).

4. The method defined in claim 3 wherein said number (UV) is defined by an equation as follows:

##EQU2## wherein AMo is defined as Amplitude of the mode and the segment is stated as DX.

5. The method defined in claim 3 wherein said number (UV) is defined by an equation as follows:

##EQU3## wherein AM is defined as Amplitude of the mean and the segment is stated as DX.

6. The method defined in claim 1 wherein said sharpness is characterized by a number proportional to the ratio of the Amplitude of the mode (AMo) to the difference between substantially the largest and substantially the smallest RR interval in a segment (Δ

X).

7. The method defined in claim 4 wherein said sharpness is characterized by a number proportional to the ratio of the Amplitude of the mode (AMo) expressed as a percentage to the difference between substantially the largest and substantially the smallest RR interval in a segment (Δ

X).

8. The method defined in claim 1 wherein said first recording is made when said first subject is in normal autonomic balance.

9. The method defined in claim 8 wherein said first and second recordings are made when said first and second subjects are performing a function chosen from the group consisting of sleep, awake resting, awake exercising, and awake recovering from exercising.

10. The method defined in claim 1 and further comprising the step of:

F) applying pacemaker stimulus to the heart of said second subject upon the occurrence of said indication.

11. The method defined in claim 1 and further comprising the step of:

F) applying electrocardioverting defibrillating stimulus to the heart of said second subject upon the occurrence of said indication.

12. Apparatus adapted to perform the method defined in claim 1, comprising

A) means for first recording a first subject'"'"'s RR or SOS intervals over substantially no less than 50 to substantially no more than 300 heart beat segments occurring with normal heart rate variability;

B) means for characterizing the sharpness of histograms of said segments comprising the numbers of each of the RR or SOS intervals recorded versus each particular RR interval as a function of the Mode of each of said segments;

C) means for second recording a second subject'"'"'s RR or SOS intervals over substantially no less than 50 to substantially no more than 300 heart beat segments;

D) means for characterizing the sharpness of the histograms of said second subject'"'"'s RR or SOS interval variations as a function of the Mode of each of said segments; and

E) means for indicating the sharpness of the histograms of said second subject deviates from predetermined limits derived from the histograms of said first subject.

13. Apparatus as defined in claim 12 further defined as comprising:

A) a module adapted to be strapped to the wrist comprising,

a) a passive RR interval detector, and

b) radio means for conveying said indication to a telephonic communications device.

14. Apparatus as defined in claim 13 wherein said telephonic communications device is a cellular telephone.

15. Apparatus as defined in claim 14 wherein said passive RR interval detector detects the second subject'"'"'s pulse.

16. Apparatus as defined in claim 13 wherein said module further comprises:

c) a motion detector, and

d) means responsive to said motion detector to distinguish between the states of wakefulness, sleep, and coma.

17. The apparatus of claim 12, wherein the means for recording the second subject'"'"'s RR intervals records the intervals as non-invasive ECG RR signals or pulse signals.

18. The method defined in claim 1 wherein said sharpness is characterized by the Amplitude of the Mean (AM) occurring in said segments.

19. The method defined in claim 18 wherein said sharpness is also characterized by a number proportional to the ratio of the Amplitude of the Mean (AM) expressed as a percentage to the difference between substantially the largest and substantially the smallest RR interval in a segment (Δ

X).

20. An apparatus for performing the method defined in claim 18 for detecting abnormal heart rate variability comprising:

A) means for first recording a first subject'"'"'s RR intervals over substantially no less than 50 to substantially no more than 300 heart beat segments occurring with normal heart rate variability;

B) means for characterizing the sharpness of histograms of said segments comprising the numbers of each of the RR intervals recorded versus each particular RR interval as a function of the Mode of each of said segments;

C) means for second recording a second subject'"'"'s RR intervals over substantially no less than 50 to substantially no more than 300 heart beat segments;

D) means for characterizing the sharpness of the histograms of said second subject'"'"'s RR interval variations as a function of the Mode of each of said segments; and

E) means for indicating when the sharpness of the histograms of said second subject deviates from predetermined limits derived from the histograms of said first subject, wherein said sharpness is characterized by the Amplitude of the Mean (AM) occurring in said segments.

21. The method defined in claim 1 wherein said sharpness is characterized by a number proportional to the ratio of the Amplitude of the Mean (AM) to the difference between substantially the largest and substantially the smallest RR interval in a segment (X).

22. The method defined in claim 1 wherein said sharpness is characterized by a number proportional to the ratio of the Amplitude of the Mean (AM) expressed as a percentage to the difference between substantially the largest and substantially the smallest RR interval in a segment (Δ

X).

23. The method defined in claim 1, wherein said sharpness is characterized by a number proportional to the ratio of the Amplitude of the mode (AMo) to the difference between substantially the largest and substantially the smallest RR interval in a segment of width at half maximum of said histogram.

24. The method defined in claim 1, wherein said sharpness is characterized by a number proportional to the ratio of the Amplitude of the mode (AMo) expressed as a percentage to the difference between substantially the largest and substantially the smallest instantaneous heart rate or RR interval in a segment of standard deviation of said histogram.

25. The method defined in claim 1, wherein said sharpness is characterized by the Amplitude of the Median occurring in said segments.

26. The method of claim 1, wherein the second subject'"'"'s intervals are recorded as non-invasive ECG RR signals or pulse signals.

54. The apparatus of claim 14, wherein the means for recording the subject'"'"'s heart beat intervals records the intervals as non-invasive ECG RR signals or pulse signals.

27. The method of operating a heart rate pacemaker regulating a patient subject'"'"'s heart comprising varying the rate of said pacemaker to induce heart rate variability to the patient subject at a desired heart rate mode.

28. The method defined in claim 27 wherein said method comprises the steps of:

A) recording a heart rate for a predetermined interval when said rate is occurring normally; and

B) using said recording to generate pacemaker signals applied to the patient subject to pace the patient subject'"'"'s heart rate in accordance with said recording.

29. The method defined in claim 28 wherein said recording is of the patient subject'"'"'s own heart rate.

30. The method of claim 27 wherein said recording is of substantially at least fifty heart beats.

31. The method of claim 27 wherein said recording is of substantially at least 100 heart beats.

32. The method of claim 27 wherein said recording is of substantially no more than 1,000 heart beats.

33. The method of claim 27 wherein said recording is of substantially no more than 300 heart beats.

34. The method defined in claim 28 wherein several said recordings are made corresponding to differing heart rate modes and each is used when the corresponding differing heart rate mode is desired.

35. The method defined in claim 27 comprising applying a series of pacemaker signals to the patient subject to provide a histographic profile of RR interval occurrences corresponding to said normal random heart rate variability of said patient subject.

36. The method defined in claim 35 wherein said histographic profile varies with the required heart rate mode.

37. The method defined in claim 27 wherein said normal random heart rate variability varies in character at differing heart rate modes.

38. The method defined in claim 27 and measuring the patient subject'"'"'s breathing state and further varying the rate of said pacemaker to correspond to the variability of the patient subject'"'"'s heart rate when in said breathing state.

39. The method defined in claim 38 and measuring one or more other of the patient subject'"'"'s stress state indicators and further varying the state of said pacemaker to correspond to the variability of the patient subject'"'"'s heart rate when said measured stress state.

40. The method defined in claim 27 wherein said varying rate is a random distribution producing a normal histogram.

41. An apparatus for performing the method defined in claim 27 comprising means for operating a heart rate pacemaker regulating a patient subject'"'"'s heart comprising, means for varying the rate of said pacemaker to correspond to random heart rate variability of the patient subject at a desired heart rate mode.

42. The method of claim 27, further comprising detecting onset of an arrythmia before the arrythmia occurs, wherein the pacemaker rate is varied in response to said detecting.

43. A method for detecting abnormal heart rate variability comprising:

A) first recording a subject'"'"'s heart beat intervals instantaneous heart rates over substantially no less than 50 to substantially no more than 300 heart beat intervals;

B) characterizing the histogram of said recorded intervals rates comprising the number of occurrences of each of the intervals or rates recorded versus each particular interval or rate to determine at least one characteristic of heart rate variability selected from the group consisting of a characteristic of sympathetic activity and a characteristic of parasympathetic activity;

C) measuring for onset of an arrythmia before the arrhythmia occurs by comparing said at least one characteristic of said histogram with at least one predetermined limit to determine if said at least one characteristic exceeds said at least one predetermined limit.

44. The method of claim 43, wherein said characteristic may be any member of the group consisting of UV, AMo, and DX.

45. The method defined in claim 44 wherein at least one of said limits is time dependent.

46. The method defined in claim 45 wherein at least one of said limits is exceeded by three or more successive recordings of substantially no less than 50 to substantially no more than 300 heart beats.

47. The method defined in claim 46 wherein said indicating step occurs when a current AMo limit is exceeded by approximately +70% or -70% of a baseline value for AMo in each recorded heart rate Mode thus indicating imbalance of the subject'"'"'s autonomic system.

48. The method defined in claim 46 wherein said indicating step occurs when a current DX limit is exceeded by approximately +70% or -70% of a baseline value for DX in each recorded heart rate Mode thus indicating imbalance of the subject'"'"'s autonomic system.

49. The method defined in claim 46 wherein said indicating step occurs when a current UV limit is exceeded by approximately +70% or -70% of a baseline value for UV in each recorded heart rate Mode thus indicating imbalance of the subject'"'"'s autonomic system.

50. An apparatus for performing the method defined in claim 43 for detecting abnormal heart rate variability comprising:

A) means for recording a subject'"'"'s heart beat intervals over substantially no less than 50 to substantially no more than 300 heart beat intervals;

B) means for characterizing the histogram of said recorded intervals comprising the number of occurrences of each of the intervals recorded versus each particular interval to determine at least one characteristic of heart rate variability selected from the group consisting of a characteristic of sympathetic activity and a characteristic of parasympathetic activity;

C) means for measuring for onset of an arrhythmia before the arrhythmia occurs by comparing said at least one characteristic of said histogram with at least one predetermined limit to determine if said at least one characteristic exceeds said at least one predetermined limit.

51. The apparatus defined in claim 50, wherein said characteristic comprises a member of the group of UV, AMo, or DX.

52. The apparatus defined in claim 50, wherein the means for characterizing determines said characteristic of sympathetic activity.

53. The apparatus defined in claim 50, wherein the means for characterizing determines said characteristic of parasympathetic activity.

55. An apparatus for performing the method defined in claim 44 further comprising a module strapped to the user'"'"'s wrist comprising,

a) a passive SOS Time Interval sensor, and

b) radio means for conveying time intervals recorded by the SOS Time Interval sensor and the characteristics of the histogram to a member selected from the group consisting of a telephonic communications device, a passive ECG heart rate sensor and an RR Time Interval sensor.

56. The apparatus as defined in claim 55, wherein said telephonic communications device is a cellular telephone comprising,

a) a strobe light, and

b) a voice microprocessor with CPR instructions, the capability of flashing the user'"'"'s front door light, and the capability of unlocking the user'"'"'s front door.

57. The apparatus as defined in claim 55, wherein said passive SOS sensor detects the time intervals of the pulse, or ECG heart rate or RR Time Interval sensor.

58. The apparatus as defined in claim 55, wherein said module further comprises:

a) a motion sensor,

b) means responsive to said motion sensor to distinguish between the states of coma, sleep, wakefulness, and physical activity,

c) a galvanic skin sensor, and

d) means responsive to said galvanic skin sensor to distinguish between the states of connectivity, or lack of connectivity to the wrist module to the user'"'"'s wrist.

59. The apparatus defined in claim 55, wherein said module further comprises:

a) a motion sensor, and

b) means responsive to said motion sensor to distinguish between the states of coma, sleep, wakefulness, and physical activity.

60. The apparatus defined in claim 55, wherein said module further comprises:

a) a galvanic skin sensor, and

b) means responsive to said galvanic skin sensor to distinguish between the states of connectivity, or lack of connectivity to the wrist module to the user'"'"'s wrist.

61. The method defined in claim 43, further comprising indicating occurrences of said at least one characteristic exceeding said predetermined limits.

62. The method defined in claim 43, further comprising sensing motion of the subject and distinguishing between the states of the subject of coma, sleep, wakefulness and physical activity.

63. The method defined in claim 43, further comprising employing a galvanic skin sensor to sense galvanic skin data, and distinguishing between states of connectivity, or lack of connectivity of the subject'"'"'s wrist to the galvanic skin sensor.

64. The method of claim 43, wherein at least one said characteristic of sympathetic activity is determined.

65. The method of claim 43, wherein at least one said characteristic of parasympathetic activity is determined.

66. The method of claim 43, wherein the subject'"'"'s heart beat intervals or instantaneous heart rates are recorded as non-invasive ECG RR signals or pulse signals.