Electrocardiographic recording method and means

• US 4,090,505 A
• Filed: 06/01/1976
• Issued: 05/23/1978
• Est. Priority Date: 06/01/1976
• Status: Expired due to Term

• Current Assignee: Marquette Electronics (General Electric Company)
• Original Assignee: Marquette Electronics (General Electric Company)
• Inventors: Mortara, David W.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/691,536
• Time in Patent Office: 721 Days
• Field of Search: 128/2.06 A, 128/2.06 B, 128/2.06 G, 128/2.05 Q, 346/33 ME
• US Class Current: 600/515
• CPC Class Codes: A61B 5/333 Recording apparatus specially adapted therefor
• CPC Class Codes: A61B 5/338 Recording by printing on paper
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period

Abstract

A method and means for graphically recording electrocardiographic data reduces the amount of redundant data displayed so as to reduce the size of the electrocardiogram. However, arrhythmias and other aberrant ekg signal complexes are reproduced in context for diagnostic purposes. Typical or normal signal complexes received from the patient are used to establish an ekg signal complex pattern. In the absence of aberrant signal complexes, this pattern is recorded in lieu of the patient data at a speed which is less than the normal recording speed to form the electrocardiogram. One such pattern may be recorded for every 25 complexes in the patient data, thereby achieving the reduction in the size of electrocardiogram. When an aberrant signal complex occurs, it is entered in the electrocardiogram at the normal higher recording speed. For repetitiously occurring aberrant signal complexes, only certain occurrences of such aberrancies are entered in the electrocardiogram. The proportionality of aberrant to normal signal complexes appearing in the electrocardiogram is thus maintained the same as that appearing in the electrocardiographic data from the patient.

Claims

1. A method of producing an electrocardiogram on a paper record movable at a slow speed and a fast speed, said electrocardiogram containing the typical and aberrant ekg signal complexes found in the electrocardiographic heart beat data from the patient, said method reducing the quantity of data so recorded by the elimination of redundancies and comprising:

identifying, in the electrocardiographic patient data, the ekg signal complexes associated with each heart beat;

establishing an ekg signal complex pattern from the complexes so identified exemplifying the typical ekg signal complexes in the patient data;

recording the ekg signal complex pattern on the movable record at the slow speed;

detecting ekg signal complexes in the patient data which are aberrant;

recording the aberrant ekg signal complex on the movable record at the fast speed.

2. The method of claim 1 further including the step of establishing a coordinating relationship between the pattern and the aberrant signal complex and the recording of the aberrant ekg signal complex is further defined as recording the aberrant ekg signal complex on the movable record responsive to the coordinating relationship at the fast speed.

3. The method of claim 2 wherein the step of establishing the coordinating relationship further comprises defining a predetermined relationship between the aberrant complex and the last typical complex in the patient data and establishing the same relationship between the ekg signal complex pattern and the aberrant signal complex.

4. The method of claim 3 wherein the step of establishing the coordinating relationship further comprises defining a predetermined point in the last typical complex in the patient data and establishing the corresponding point in the ekg signal complex pattern as a switchover point for recording the aberrant ekg signal complex.

5. The method of claim 4 wherein the step of recording the aberrant signal complex on the movable record is further defined as accelerating the record to the fast speed when the aberrant complex is detected;

completing the recording of the ekg signal complex pattern at the fast speed; and

switching over to the recording the aberrant ekg signal complex at the fast speed at the switch over point.

6. The method of claim 3 wherein the step of establishing the coordinating relationship further comprises establishing corresponding reference points in the aberrant signal complex, the last typical complex, and the ekg signal complex pattern, defining by means of the reference points in the aberrant signal complex and last typical complex a predetermined point and establishing the corresponding point in the ekg signal complex pattern by means of the reference point in the pattern.

7. The method according to claim 6 wherein the step of establishing the coordinating relationship further comprises defining the predetermined point and establishing the corresponding point to include a portion of the last typical beat of the ekg data.

8. The method according to claim 2 wherein the aberrant signal complexes occur repetitiously in the patient data and wherein said method further includes the step of ascertaining the proportion of aberrant signal complexes to typical signal complexes appearing in patient data and the recording steps are further defined as recording a corresponding number of ekg signal complex patterns and aberrant signal complexes in the electrocardiogram.

9. The method according to claim 8 wherein said method further comprises selecting an aberrant signal complex from said patient data suitable for recording and recording same in the electrocardiogram.

10. The method of claim 9 wherein said method further comprises determining, by means of said proportion, the number of aberrant signal complexes which will appear in the patient data during the recording of the ekg signal complex patterns;

sensing receipt of a corresponding number (N) of aberrant signal complexes; and

recording the Nth aberrant signal complex.

11. The method of claim 10 wherein the determining step is further defined as reducing the determined number of aberrant signal complexes by a number selected in accordance with the coordinating relationship of the ekg signal complex pattern and the aberrant signal complex and sufficient to maintain the correct proportion of ekg signal complex patterns and aberrant signal complexes in the electrocardiogram.

12. The method of claim 11 wherein the determining step is further defined as reducing the determined number of aberrant signal complexes by a number equal to the number of aberrant signal complexes corresponding to a preselected portion of an ekg signal complex pattern.

13. The method of claim 12 wherein the determining step is further defined as reducing the determined number of aberrant signal complexes by a number corresponding to half an ekg signal complex pattern.

14. The method of claim 8 further defined as including the step of recording the initial occurrence of an aberrant signal complex in the electrocardiogram.

15. The method of claim 8 further defined as including the step of recording the sequential occurrence of aberrant signal complexes in the electrocardiogram.

16. The method of claim 8 wherein said method further comprises selecting an aberrant signal complex of each type from said patient data suitable for recording and recording same in the electrocardiogram.

17. The method of claim 16 wherein said method further comprises ascertaining the proportion of the total number of aberrant signal complexes of all types to typical signal complexes appearing in the patient data;

determining by means of said proportion, the total number of aberrant signal complexes which will appear in the patient data during the recording of the ekg signal complex patterns;

sensing the receipt of a corresponding number (N) of aberrant signal complexes of each type; and

recording the Nth aberrant signal complex of each type.

18. The method of claim 17 wherein the determining step is further defined as reducing the determined number of aberrant signal complexes by a number selected in accordance with the coordinating relationship of the ekg signal complex pattern and the aberrant signal complex and sufficient to maintain the correct proportion of ekg signal complex patterns and aberrant signal complexes.

19. The method according to claim 18 wherein the determining step is further defined as reducing the determined number of aberrant signal complexes by a number equal to the number of aberrant signals corresponding to a preselected portion of an ekg signal complex.

20. The method according to claim 19 wherein the determining step is further defined as reducing the determined number of aberrant signal complexes by a number corresponding to half an ekg signal complex pattern.

21. The method of claim 2 wherein aberrant signal complexes of differing types occur repetitiously in the patient data and wherein said method further includes the step of classifying the aberrant signal complexes as to type;

ascertaining the proportion of differing types aberrant signal complexes to typical signal complexes appearing in patient data and the recording steps are further defined as recording a corresponding number of ekg signal complex patterns and aberrant signal complex of differing types in the electrocardiogram.

22. The method of claim 21 wherein the step of classifying the aberrant signal complexes is further defined as storing the initial occurrence of differing types of aberrant signal complexes and comparing subsequently received aberrant signal complexes with the stored data to classify and subsequently received aberrant signal complexes as to type.

23. The method of claim 22 wherein the comparison step is further defined as comparing subsequently received aberrant signal complexes on the basis of shape and timing for classifying the subsequently received aberrant signal complexes as to type.

24. The method of claim 23 wherein the comparison step is further defined as comparing the subsequently received aberrant signal complexes against the ekg signal complex pattern for classifying as to type with respect to timing.

25. The method according to claim 22 further defined as including the step of recording the initial occurrence of an aberrant signal complex of each type in the electrocardiogram.

26. The method according to claim 22 further defined as including the step of recording the sequential occurrence of aberrant signal complexes in the electrocardiogram.

27. The method according to claim 22 further defined as including the step of recording each occurrence of preselected types of aberrant signal complexes.

28. The method of claim 1 wherein the step of identifying the ekg signal complexes in the patient data includes sensing a preselected magnitudinal characteristic in each heart beat of the ekg data.

29. The method of claim 28 wherein the identifying step further includes selecting in the patient data a sufficient portion thereof adjacent said magnitudinal characteristic to comprise the complex associated with a heart beat.

30. The method of claim 29 wherein the identifying step is further defined as ascertaining the interval between heart beats in the patient data and selecting the portion of the patient data surrounding each magnitudinal characteristic corresponding to one such interval to comprise a signal complex.

31. The method of claim 1 wherein the incoming data is in analog form, said method including the preliminary step of converting the data to digital form and the recording steps are defined as converting the digital data to an analog recording.

32. The method of claim 1 wherein the step of establishing an ekg signal complex pattern is further defined as forming an ekg signal complex pattern, comparing the pattern so established with subsequent ekg signal complexes to ascertain any differences therebetween and altering the established ekg signal complex pattern responsive to differences within predetermined amounts to reform the ekg signal complex pattern.

33. The method according to claim 32 wherein the step of establishing the ekg signal complex pattern is further defined as altering the established ekg signal complex pattern by a predetermined portion of any differences to reform the ekg signal complex pattern.

34. The method of claim 1 wherein the step of detecting aberrant signal complexes is further defined as detecting ekg signal complexes in the patient data which are aberrant with respect to the ekg signal complex pattern.

35. The method according to claim 34 wherein the step of detecting aberrant ekg signal complexes is further defined as detecting complexes as aberrant which differ from the ekg signal complex pattern in excess of a predetermined amount.

36. The method of claim 34 wherein the step of detecting aberrant ekg signal complexes is further defined as ascertaining the heart beat rate reflected in the ekg signal complexes in the patient data;

comparing this heart beat rate with that reflected by the ekg signal complex pattern; and

identifying a complex as aberrant when the heart beat rate difference exceeds a predetermined amount.

37. The method of claim 34 wherein the step of detecting aberrant ekg signal complexes is further defined as ascertaining the amplitude of the ekg signal complexes in the patient data;

comparing the amplitude of the complexes with that of the ekg signal complex pattern; and

identifying a complex aberrant when the amplitudinal difference exceeds a predetermined amount.

38. The method of claim 37 wherein the step of detecting aberrant ekg signal complexes is further defined as ascertaining the amplitude of a predetermined sample of the ekg signal complexes in the patient data;

comparing the amplitude of the sampled data with a corresponding portion of the ekg signal complex pattern; and

identifying a complex as aberrant when the amplitudinal difference exceeds a predetermined amount.

39. The method of claim 38 wherein, in the comparative step, the amplitudinal difference is determined by squaring and summing the amplitudinal differences between the sampled data and the corresponding portion of the ekg signal complex pattern.

40. The method according to claim 37 wherein the step of detecting an aberrant ekg signal complex is further defined as ascertaining the heart beat rate reflected in the ekg signal complexes in the patient data;

comparing this heart beat rate with that reflected by the ekg signal complex pattern; and

identifying a complex as aberrant when the heart beat rate or amplitudinal difference exceeds a predetermined amount.

41. Apparatus for producing an electrocardiogram containing the typical and aberrant signal complexes found in the electrocardiographic heart beat signal from the patient, said apparatus comprising:

input means for receiving the electrocardiographic signals from the patient;

signal processing means coupled to said input means for identifying the ekg signal complex associated with each heart beat;

comparator means coupled to said signal processing means for ascertaining typical and aberrant signal complexes;

pattern register means coupled to said comparator for establishing a typical ekg signal complex pattern from said typical ekg signal complexes;

recording means operable at a slow speed and at a fast speed for making a graphic recording, said means being coupled to said pattern register for recording said pattern at the slow speed; and

aberrant signal complex signal processing means coupled to said comparator means for receiving the aberrant signal complexes, said signal processing means being coupled to said recording means for recording the aberrant signal complexes at the fast speed.

42. The apparatus of claim 41 including coordinating means coupled to said pattern register means and to said aberrant signal complex register means for coordinating the operation of said recording means and the slow speed recording of said pattern and fast speed recording of said aberrant signal complexes.

43. The apparatus of claim 41 including analog-to-digital conversion means couplable to said input means for converting the analog electrocardiographic signals from the patient to digital data and wherein the recording means includes digital-to-analog conversion means for making an analog graphic recording.

44. The apparatus of claim 41 wherein said signal processing means includes means for sensing a preselected characteristic in the electrocardiographic signals from the patient for identifying the ekg signal complexes.

45. The apparatus of claim 44 wherein said signal processing means includes means for defining the portion of electrocardiographic signals comprising the signal complex associated with each heart beat.

46. The apparatus of claim 41 wherein said pattern register means is further coupled to said comparator for providing said pattern to said comparator for comparison against the ekg signal complexes to ascertain typical or aberrant signal complexes.

47. The apparatus of claim 46 wherein said pattern register means includes updating means for altering said established signal complex pattern responsive to differences of a predetermined amount resulting from said comparison.

48. The apparatus of claim 47 wherein said updating means is further defined as means for altering the established signal complex pattern by a predetermined portion of the difference resulting from comparison.

49. The apparatus of claim 46 wherein said comparator includes means for comparing the heart beat rate of the signal complexes with that of the ekg signal complex pattern.

50. The apparatus of claim 46 wherein said comparator includes means for comparing the magnitude of the signal complexes with that of the ekg signal complex pattern.

51. The apparatus of claim 50 wherein said magnitude comparison means includes means for selecting a predetermined sample of each ekg signal complex and a corresponding sample of said pattern and comparing the magnitudinal differences of the samples.

52. The apparatus of claim 51 wherein said magnitude comparison means includes means for squaring and summing the magnitudinal differences and for comparing the sum to a predetermined level for ascertaining aberrancy.

53. The apparatus of claim 41 further defined as for use with electrocardiographic heart beat signals in which aberrant signal complexes occur repetitiously, said aberrant signal complex signal processing means including counting means coupled to said comparator for ascertaining the proportion of aberrant to typical signal complexes appearing in the heart beat signals, said counting means being coupled to said recording means for recording a corresponding number of ekg signal complex patterns and aberrant signal complexes in the electrocardiogram.

54. The apparatus of claim 53 wherein said counting means is further defined as means for selecting a given aberrant signal complex from the aberrant signal complexes in the electrocardiographic signals from the patient suitable for recording and recording same.

55. The apparatus of claim 54 wherein said counting means is further defined as establishing a number in accordance with the proportion of aberrant to typical signal complexes and counting said aberrant signal complexes for selecting the given aberrant signal complex in accordance with the established number.

56. The apparatus of claim 55 wherein said counting means is further defined as containing means for altering the number in the counter by an amount sufficient to secure proper entry of the aberrant signal complexes in the electrocardiogram.

57. The apparatus of claim 55 suitable for use with electrocardiographic heart beat signals in which aberrant signal complexes of differing types occur repetitiously and wherein said aberrant signal complex signal processing means includes classifier means coupled to said comparator and said counter for classifying the aberrant signal complexes as to type and wherein said counter counts said types of aberrant signal complexes for selecting aberrant signal complexes for recording in the electrocardiogram.

58. The apparatus of claim 57 wherein said classifier means includes aberrant signal complex storage means for storing aberrant signal complex data for comparative purposes.

59. The apparatus of claim 53 wherein said aberrant signal complex signal processing means includes means coupled to said comparator and to said recording means for recording the initial occurrences of an aberrant signal complex in the electrocardiogram.

60. The apparatus of claim 59 wherein said classifier means is coupled to said ekg signal complex pattern register means for receiving said pattern for comparative purposes.

61. The apparatus of claim 53 wherein said aberrant signal complex signal processing means includes means coupled to said comparator and to said recording means for recording sequential occurrences of aberrant signal complexes in the electrocardiogram.