Method and system for diagnosing and administering therapy of pulmonary congestion

• US 6,595,927 B2
• Filed: 07/23/2001
• Issued: 07/22/2003
• Est. Priority Date: 07/23/2001
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Van Oort, Geeske, Pitts-Crick, Jonathan
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US09/909,960
• Publication Number:
  US 20030023184A1
• Time in Patent Office: 729 Days
• Field of Search: 600/547, 600/529, 600/508, 600/513, 607/17-23
• US Class Current: 600/529
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/29 for permanent or long-term implantation
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters

Abstract

A method of diagnosing pulmonary congestion is provided. At least one decrease in a trans-thoracic impedance value from a baseline trans-thoracic impedance value is sensed. At least one increase in a heart rate value from a baseline heart rate value is also sensed. Pulmonary congestion is diagnosed if the decrease in the trans-thoracic impedance value corresponding to the increase in the heart rate does not increase after a predetermined interval. Systems and programs incorporating the method are also provided.

Claims

1. A method of diagnosing pulmonary congestion, comprising:

sensing at least one decrease in a trans-thoracic impedance value from a baseline trans-thoracic impedance value;

sensing at least one increase in a heart rate value from a baseline heart rate value; and

diagnosing pulmonary congestion if the decrease in the trans-thoracic impedance value corresponding to the increase in the heart rate does not increase after a predetermined interval.

2. The method of claim 1, further comprising:

determining the baseline trans-thoracic impedance value.

3. The method of claim 1, further comprising:

determining the baseline heart rate value.

4. The method of claim 1, further comprising:

determining the predetermined interval.

5. The method of claim 1, further comprising:

determining the trans-thoracic impedance value.

6. The method of claim 5, wherein determining the trans-thoracic impedance value comprises:

delivering an excitation current pulse between a first electrode and a second electrode; and

sensing the trans-thoracic impedance between the first electrode and the second electrode.

7. The method of claim 6, wherein at least one of the first electrode and the second electrode is disposed within an atrium.

8. The method of claim 6, wherein at least one of the first electrode and the second electrode is disposed within a ventricle.

9. The method of claim 1, wherein the trans-thoracic impedance value is an average determined from a plurality of trans-thoracic impedance values.

10. The method of claim 1, wherein sensing the increase in the heart rate value comprises:

sensing the heart rate value with an activity sensor.

11. The method of claim 1, wherein sensing the increase in the heart rate value comprises:

sensing the heart rate value with an QT sensor.

12. The method of claim 1, wherein sensing the increase in the heart rate value comprises:

sensing the heart rate value with a rate-responsive sensor.

13. The method of claim 1, further comprising:

determining a lowest trans-thoracic impedance value.

14. The method of claim 13 wherein the trans-thoracic impedance value tends toward the lowest-trans-thoracic impedance value, comprising:

diagnosing severe pulmonary congestion.

15. The method of claim 1, further comprising:

determining a maximum trans-thoracic impedance value.

16. The method of claim 1, further comprising:

determining at least one predetermined impedance value, the predetermined impedance value indicating a level of pulmonary congestion.

17. The method of claim 16, further comprising:

determining if the decrease in the trans-thoracic impedance value is greater than the predetermined impedance value;

determining a maximum trans-thoracic impedance value;

determining if the decrease in the trans-thoracic impedance value is greater than the maximum trans-thoracic impedance value; and

diagnosing mild pulmonary congestion if the decrease is greater than the predetermined impedance value but less than the maximum trans-thoracic impedance value.

18. The method of claim 1, further comprising:

determining a degree of pulmonary congestion based on the decrease in the trans-thoracic impedance value.

19. The method of claim 18, further comprising:

administering therapy based on the degree of pulmonary congestion.

20. The method of claim 19, wherein administering therapy further comprises:

transmitting an electrical stimulation to the cardiac tissue.

21. The method of claim 19, wherein administering therapy further comprises:

providing an alert indicating that therapy should be administered.

22. The method of claim 19, wherein administering therapy further comprises:

delivering at least one drug to the cardiac tissue.

23. The method of claim 22, wherein the drug is a nitrate.

24. An implantable medical device comprising:

a processor;

at least one impedance sensor operably connected to the processor, wherein

the sensor senses at least one decrease in a trans-thoracic impedance value from a baseline trans-thoracic impedance value, the trans-thoracic impedance value corresponding to an increase in heart rate and the processor diagnoses pulmonary congestion if the decrease in the trans-thoracic impedance value does not increase after a predetermined interval.

25. The device of claim 24 further comprising:

at least one pacing lead.

26. The device of claim 24 further comprising:

a first electrode; and

a second electrode wherein

the decrease in the trans-thoracic impedance is sensed by delivering an excitation current pulse between the first and the second electrode.

27. The device of claim 24 wherein the processor determines the trans-thoracic impedance as an average of impedance values over a predetermined interval.

28. The device of claim 24 further comprising:

a rate responsive sensor to determine heart rate.

29. The device of claim 24 further comprising:

a QT sensor to determine heart rate.

30. The device of claim 24 further comprising:

an activity sensor to determine heart rate.

31. The device of claim 24 further comprising:

an alert to indicate therapy should be administered.

32. The device of claim 24, further comprising:

drug delivery means.

33. The device of claim 24, further comprising:

at least one stimulating lead.

34. An implantable medical system, comprising:

means for sensing at least one decrease in a trans-thoracic impedance value from a baseline trans-thoracic impedance value;

means for sensing at least one increase in a heart rate value from a baseline heart rate value; and

means for diagnosing pulmonary congestion if the decrease in the trans-thoracic impedance value corresponding to the increase in the heart rate does not increase after a predetermined interval.

35. The system of claim 34, further comprising:

means for determining the baseline trans-thoracic impedance value.

36. The system of claim 34, further comprising:

means for determining the baseline heart rate value.

37. The system of claim 34, further comprising:

means for determining the predetermined interval.

38. The system of claim 34, further comprising:

means for determining the trans-thoracic impedance value.

39. The system of claim 34, further comprising:

means for delivering an excitation current pulse between a first electrode and a second electrode; and

means for sensing the trans-thoracic impedance between the first electrode and the second electrode.

40. The system of claim 34, further comprising:

means for determining an average trans-thoracic impedance value.

41. The system of claim 34, further comprising:

means for sensing the heart rate value with an activity sensor.

42. The system of claim 34, further comprising:

means for sensing the heart rate value with an QT sensor.

43. The system of claim 34, further comprising:

means for sensing the heart rate value with a rate-responsive sensor.

44. The system of claim 34, further comprising:

means for determining a lowest trans-thoracic impedance value.

45. The system of claim 34, further comprising:

means for diagnosing severe pulmonary congestion.

46. The system of claim 34, further comprising:

means for determining a maximum trans-thoracic impedance value.

47. The system of claim 34, further comprising:

means for determining at least one predetermined impedance value, the predetermined impedance value indicating a level of pulmonary congestion.

48. The system of claim 47, further comprising:

means for determining if the decrease in the trans-thoracic impedance value is greater than the predetermined impedance value;

means for determining a maximum trans-thoracic impedance value;

means for determining if the decrease in the trans-thoracic impedance value is greater than the maximum trans-thoracic impedance value; and

means for diagnosing mild pulmonary congestion if the decrease is greater than the predetermined impedance value but less than the maximum trans-thoracic impedance value.

49. The system of claim 34, further comprising:

means for determining a degree of pulmonary congestion based on the decrease in the trans-thoracic impedance value.

50. The system of claim 34, further comprising:

means for administering therapy based on the degree of pulmonary congestion.

51. The system of claim 34, further comprising:

means for transmitting an electrical stimulation to the cardiac tissue.

52. The system of claim 34, further comprising:

means for providing an alert indicating that therapy should be administered.

53. The system of claim 34, further comprising:

means for delivering at least one drug to the cardiac tissue.

68. The program of claim 47, further comprising:

computer program code that determines if the decrease in the trans-thoracic impedance value is greater than the predetermined impedance value;

computer program code that determines a maximum trans-thoracic impedance value;

computer program code that determines if the decrease in the trans-thoracic impedance value is greater than the maximum trans-thoracic impedance value; and

computer program code that diagnoses mild pulmonary congestion if the decrease is greater than the predetermined impedance value but less than the maximum trans-thoracic impedance value.

54. A computer usable medium including a program for diagnosing pulmonary congestion, comprising:

computer program code that senses at least one decrease in a trans-thoracic impedance value from a baseline trans-thoracic impedance value;

computer program code that senses at least one increase in a heart rate value from a baseline heart rate value; and

computer program code that diagnoses pulmonary congestion if the decrease in the trans-thoracic impedance value corresponding to the increase in the heart rate does not increase after a predetermined interval.

55. The program of claim 54, further comprising:

computer program code that determines the baseline trans-thoracic impedance value.

56. The program of claim 54, further comprising:

computer program code that determines the baseline heart rate value.

57. The program of claim 54, further comprising:

computer program code that determines the predetermined interval.

58. The program of claim 54, further comprising:

computer program code that determines the trans-thoracic impedance value.

59. The program of claim 54, further comprising:

computer program code that delivers an excitation current pulse between a first electrode and a second electrode; and

computer program code that senses the trans-thoracic impedance between the first electrode and the second electrode.

60. The program of claim 54, further comprising:

computer program code that determines an average trans-thoracic impedance value.

61. The program of claim 54, further comprising:

computer program code that senses the heart rate value with an activity sensor.

62. The program of claim 54, further comprising:

computer program code that senses the heart rate value with an QT sensor.

63. The program of claim 54, further comprising:

computer program code that senses the heart rate value with a rate-responsive sensor.

64. The program of claim 54, further comprising:

computer program code that determines a lowest trans-thoracic impedance value.

65. The program of claim 54, further comprising:

computer program code that diagnoses severe pulmonary congestion.

66. The program of claim 54, further comprising:

computer program code that determines a maximum trans-thoracic impedance value.

67. The program of claim 54, further comprising:

computer program code that determines at least one predetermined impedance value, the predetermined impedance value indicating a level of pulmonary congestion.

69. The program of claim 54, further comprising:

computer program code that determines a degree of pulmonary congestion based on the decrease in the trans-thoracic impedance value.

70. The program of claim 54, further comprising:

computer program code that administers therapy based on the degree of pulmonary congestion.

71. The program of claim 54, further comprising:

computer program code that transmits an electrical stimulation to the cardiac tissue.

72. The program of claim 54, further comprising:

computer program code that provides an alert indicating that therapy should be administered.

73. The program of claim 54, further comprising:

computer program code that delivers at least one drug to the cardiac tissue.