Techniques for applying, configuring, and coordinating nerve fiber stimulation

• US 20050267542A1
• Filed: 02/22/2005
• Published: 12/01/2005
• Est. Priority Date: 08/31/2001
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: BioControl Medical (B.C.M) Ltd.
• Inventors: Cohen, Ehud, Ayal, Shai, David, Tamir B., Ezra, Omry B.
• Granted Patent: US 7,974,693 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/4029 for evaluating the peripheral nervous systems A61B5/24 takes precedence
• CPC Class Codes: A61B 5/4041 Evaluating nerves condition
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/0556 Cuff electrodes
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy

Abstract

Apparatus is provided including an implantable sensor, adapted to sense an electrical parameter of a heart of a subject, and a first control unit, adapted to apply pulses to the heart responsively to the sensed parameter, the pulses selected from the list consisting of: pacing pulses and anti-arrhythmic energy. The apparatus further includes an electrode device, adapted to be coupled to a site of the subject selected from the list consisting of: a vagus nerve of the subject, an epicardial fat pad of the subject, a pulmonary vein of the subject, a carotid artery of the subject, a carotid sinus of the subject, a coronary sinus of the subject, a vena cava vein of the subject, a right ventricle of the subject, and a jugular vein of the subject; and a second control unit, adapted to drive the electrode device to apply to the site a current that increases parasympathetic tone of the subject and affects a heart rate of the subject. The first and second control units are not under common control. At least one of the control units is adapted to coordinate an aspect of its operation with an aspect of operation of the other control unit. Other embodiments are also described.

Claims

1. Apparatus comprising:

an implantable sensor, adapted to sense an electrical parameter of a heart of a subject;

a first control unit, adapted to apply pulses to the heart responsively to the sensed parameter, the pulses selected from the list consisting of;

pacing pulses and anti-arrhythmic energy;

an electrode device, adapted to be coupled to a site of the subject selected from the list consisting of;

a vagus nerve of the subject, an epicardial fat pad of the subject, a pulmonary vein of the subject, a carotid artery of the subject, a carotid sinus of the subject, a coronary sinus of the subject, a vena cava vein of the subject, a right ventricle of the subject, and a jugular vein of the subject; and

a second control unit, adapted to drive the electrode device to apply to the site a current that increases parasympathetic tone of the subject and affects a heart rate of the subject,

wherein the first and second control units are not under common control, and

wherein at least one of the control units is adapted to coordinate an aspect of its operation with an aspect of operation of the other control unit.

2. The apparatus according to claim 1, wherein the second control unit is adapted to generate a communication signal indicative of driving the electrode device to apply the current, and wherein the first control unit is adapted to receive the communication signal, and to regulate an aspect of its own operation responsively to receiving the communication signal.

4. The apparatus according to claim 1, wherein the implantable sensor, the first control unit, the electrode device, and the second control unit are packaged in a single integrated unit.

5. The apparatus according to claim 1, wherein the second control unit is adapted to drive the electrode device responsively to the sensed parameter.

6. The apparatus according to claim 1,

wherein the aspect of the operation of the first control unit includes an aspect of timing of the operation of the first control unit,

wherein the aspect of the operation of the second control unit includes an aspect of timing of the operation of the second control unit, and

wherein the at least one of the control units is adapted to coordinate the aspect of the timing of the operation of the first control unit with the aspect of the timing of the operation of the second control unit.

7. The apparatus according to claim 1, wherein the implantable sensor and the first control unit together comprise an implantable cardioverter defibrillator (ICD).

8. The apparatus according to claim 1, wherein the implantable sensor and the first control unit together comprise a pacemaker.

9. The apparatus according to claim 1, wherein the implantable sensor and the first control unit together comprise a pulse generator.

10. The apparatus according to claim 1, wherein the second control unit is configured to reduce a likelihood that the current causes the first control unit to falsely detect arrhythmia of the subject.

11. The apparatus according to claim 1, wherein the at least one of the control units is configured to reduce a likelihood of an occurrence of a “

tug-of-war”

between the first and second control units.

12. The apparatus according to claim 1, wherein the first control unit is programmed with a flag indicative of the presence of the second control unit, and wherein the first control unit is adapted to withhold coordinating the aspect of the operation responsively to a value of the flag that indicates that the second control unit is not present.

13. The apparatus according to claim 1, wherein the second control unit is programmed with a flag indicative of the presence of the first control unit, and wherein the at least one of the control units is adapted to withhold coordinating the aspect of the operation responsively to a value of the flag that indicates that the first control unit is not present.

14. The apparatus according to claim 1, wherein the second control unit is adapted to generate a communication signal when driving the electrode device to apply the current, and wherein the first control unit is adapted to receive the signal, and, responsively thereto, to withhold applying the pulses.

15. The apparatus according to claim 1, wherein the first control unit is adapted to withhold attempting to detect a next heart beat during an extended blanking period following detection of a previous heart beat.

17. The apparatus according to claim 15, wherein the second control unit is adapted to drive the electrode device to apply the current only during the extended blanking period.

18. The apparatus according to claim 1, wherein the site includes the vagus nerve, and wherein the electrode device is adapted to be coupled to the vagus nerve.

19. The apparatus according to claim 18, wherein the second control unit is adapted to configure the current to include a stimulating current, which is capable of inducing action potentials in a first set and a second set of nerve fibers of the vagus nerve, and an inhibiting current, which is capable of inhibiting the induced action potentials traveling in the second set of nerve fibers, the nerve fibers in the second set having generally larger diameters than the nerve fibers in the first set.

20. The apparatus according to claim 18, wherein the second control unit is adapted to configure the current to include a stimulating current, which is capable of inducing action potentials in the vagus nerve, and an inhibiting current, which is capable of inhibiting action potentials induced by the stimulating current and traveling in the vagus nerve in an afferent direction toward a brain of the subject.

21. The apparatus according to claim 1, wherein the first control unit is adapted to generate a communication signal at each detection of a feature of a cardiac cycle of the subject, and wherein the second control unit is adapted to receive the signal, and to time an aspect of the application of the current responsively to the signal.

23. The apparatus according to claim 1, wherein the second control unit is adapted to, upon detection of suspected arrhythmia, drive the electrode device to apply the current, and to configure the current to reduce a ventricular rate.

24. The apparatus according to claim 23, wherein the implantable sensor and the first control unit together comprise an implantable cardioverter defibrillator (ICD), and wherein the ICD is adapted to apply defibrillation to the heart if the applied current does not sufficiently reduce the ventricular rate.

25. The apparatus according to claim 1,

wherein the first control unit is adapted to detect ventricular fibrillation (VF), to generate a communication signal responsive to the detection, and to withhold generating the signal after the detection ceases, and

wherein the second control unit is adapted to receive the signal, and, responsively thereto, to withhold driving the electrode device to apply the current until cessation of the signal.

26. The apparatus according to claim 1, wherein the second control unit is adapted to detect ventricular fibrillation (VF), and, responsively thereto, to withhold driving the electrode device to apply the current until cessation of the VF.

27. The apparatus according to claim 1,

wherein the first control unit is adapted to detect ventricular tachycardia (VT), to generate a communication signal responsive to the detection, and to withhold generating the signal after the detection ceases, and

wherein the second control unit is adapted to receive the signal, and, responsively thereto, to withhold driving the electrode device to apply the current until cessation of the signal.

28. The apparatus according to claim 1, wherein the second control unit is adapted to detect ventricular tachycardia (VT), and, responsively thereto, to withhold driving the electrode device to apply the current until cessation of the VT.

29. The apparatus according to claim 1,

wherein the first control unit is adapted to generate a communication signal when applying pulses to the heart, and to withhold generating the signal when not applying the pulses, and

wherein the second control unit is adapted to receive the signal, and, responsively thereto, to withhold driving the electrode device to apply the current until a certain amount of time after cessation of the signal.

30. The apparatus according to claim 1, wherein the second control unit is adapted to drive the electrode device to apply the current during at least one period selected from the list consisting of:

a refractory period of the heart, and a blanking period of the first control unit.

32. The apparatus according to claim 1, wherein the first control unit is adapted to apply the pulses only when the heart rate is within a first set of values, and wherein the second control unit is adapted to drive the electrode device to apply the current only when the heart rate is within a second set of values.

33. The apparatus according to claim 32, wherein the first and second sets of values are non-overlapping.

34. The apparatus according to claim 33, wherein the first set of values includes values greater than 190 beats per minute and less than 60 beats per minute, and the second set of values includes values between 70 and 180 beats per minute.

3. (canceled)

16. (canceled)

22. (canceled)

31. (canceled)

35-43. -43. (canceled)

44. Apparatus comprising:

an electrode device, adapted to be coupled to a site of a subject selected from the list consisting of;

a vagus nerve of the subject, an epicardial fat pad of the subject, a pulmonary vein of the subject, a carotid artery of the subject, a carotid sinus of the subject, a coronary sinus of the subject, a vena cava vein of the subject, a right ventricle of the subject, and a jugular vein of the subject;

a sensing element, adapted to sense a physiological parameter of a heart of the subject;

an implantable device adapted to apply pulses to the heart, the pulses selected from the list consisting of;

pacing pulses and anti-arrhythmic energy; and

a control unit, adapted to;

detect a life-threatening arrhythmia (LTA) responsively to the sensed physiological parameter,

responsively to the detection of the LTA, drive the electrode device to apply to the site a current that increases parasympathetic tone of the subject,

determine whether the LTA has been resolved,

responsively to a determination that the LTA has not been resolved, determine whether to drive the implantable device to apply the pulses to the heart,

responsively to an affirmative determination to drive the implantable device, drive the implantable device to apply the pulses to the heart, and

responsively to a determination not to drive the implantable device, drive the electrode device to apply the current to the site.

45. The apparatus according to claim 44, wherein the control unit is adapted to change a parameter of the current applied to the site, after the determination not to drive the implantable device.

46. The apparatus according to claim 44, wherein the implantable device comprises an implantable cardioverter defibrillator (ICD).

47. The apparatus according to claim 44, wherein the implantable device comprises a pacemaker.

48. The apparatus according to claim 44, wherein the parameter includes a feature of an electrocardiogram (ECG) signal, and wherein the sensing element is adapted to sense the feature.

49. The apparatus according to claim 44, wherein the control unit is adapted to determine to drive the implantable device to apply the pulses only if the control unit determines that only driving the electrode device to apply the current is unlikely to resolve the LTA.

50. Apparatus comprising:

an electrode device, adapted to be coupled to a site of a subject selected from the list consisting of;

a vagus nerve of the subject, an epicardial fat pad of the subject, a pulmonary vein of the subject, a carotid artery of the subject, a carotid sinus of the subject, a coronary sinus of the subject, a vena cava vein of the subject, a right ventricle of the subject, and a jugular vein of the subject;

a sensing element, adapted to sense a physiological parameter of a heart of the subject;

an implantable device adapted to apply pulses to the heart, the pulses selected from the list consisting of;

pacing pulses and anti-arrhythmic energy; and

a control unit, adapted to;

drive the electrode device to apply to the site a current that increases parasympathetic tone of the subject,

detect a life-threatening arrhythmia (LTA) responsively to the sensed physiological parameter,

responsively to the detection of the LTA, modify at least one current parameter of the applied current,

determine whether the LTA has been resolved,

responsively to a determination that the LTA has not been resolved, determine whether to drive the implantable device to apply the pulses to the heart,

responsively to an affirmative determination to drive the implantable device, drive the implantable device to apply the pulses to the heart, and

responsively to a determination not to drive the implantable device, modify one or more current parameters of the applied current.

51. The apparatus according to claim 50, wherein the implantable device comprises an implantable cardioverter defibrillator (ICD).

52. The apparatus according to claim 50, wherein the implantable device comprises a pacemaker.

53. The apparatus according to claim 50, wherein the parameter includes a feature of an electrocardiogram (ECG) signal, and wherein the sensing element is adapted to sense the feature.

54. The apparatus according to claim 50, wherein the control unit is adapted to determine to drive the implantable device to apply the pulses only if the control unit determines that only driving the electrode device to apply the current is unlikely to resolve the LTA.

55. A method comprising:

sensing, from within a body of a subject, an electrical parameter of a heart of the subject;

applying, from a first implantation site within the body, pulses to the heart responsive to the parameter, the pulses selected from the list consisting of;

pacing pulses and anti-arrhythmic energy;

applying, at a second implantation site within the body, a current that increases parasympathetic tone of the subject and affects a heart rate of the subject, the second implantation site selected from the list consisting of;

a vagus nerve of the subject, an epicardial fat pad of the subject, a pulmonary vein of the subject, a carotid artery of the subject, a carotid sinus of the subject, a coronary sinus of the subject, a vena cava vein of the subject, a right ventricle of the subject, and a jugular vein of the subject; and

coordinating an aspect of applying the pulses with an aspect of applying the current, without providing a controller that regulates both the applying of the pulses and the applying of the current.

56. The method according to claim 55, wherein applying the current at the second implantation site comprises applying the current responsively to the sensed electrical parameter.

57. The method according to claim 55, wherein applying the current comprises generating a communication signal indicative of applying the current, and wherein applying the pulses comprises receiving the communication signal, and regulating an aspect of the applying of the pulses responsively to receiving the communication signal.

58. The method according to claim 55, wherein sensing the electrical parameter comprises implanting, in the subject, a device for sensing the electrical parameter, and wherein applying the pulses comprises applying the pulses from the device.

60. The method according to claim 58,

wherein the aspect of applying the pulses includes an aspect of timing of applying the pulses,

wherein the aspect of applying the current includes an aspect of timing of applying the current, and

wherein coordinating comprises coordinating the aspect of timing of applying the pulses with the aspect of timing of applying the current.

61. The method according to claim 58, wherein sensing the parameter comprises analyzing the parameter to detect arrhythmia of the subject, and wherein coordinating comprises coordinating so as to reduce a likelihood that applying the current causes false detection of the arrhythmia.

62. The method according to claim 58, wherein sensing the parameter comprises identifying a stimulus artifact of the current application as being a stimulus artifact of the current application.

63. The method according to claim 58, wherein applying the current comprises generating a communication signal when applying the current, and wherein applying the pulses comprises receiving the signal, and, responsively thereto, withholding applying the pulses.

64. The method according to claim 58, wherein sensing the parameter comprises withholding attempting to detect a next heart beat during an extended blanking period following detection of a previous heart beat.

65. The method according to claim 58, wherein the second implantation site includes the vagus nerve, and wherein applying the current comprises applying the current to the vagus nerve.

66. The method according to claim 58, wherein applying the current comprises applying the current during at least one period selected from the list consisting of:

a refractory period of the heart, and a blanking period of the device.

67. The method according to claim 58, wherein applying the pulses comprises applying the pulses only when the heart rate is within a first set of values, and applying the current comprises applying the current only when the heart rate is within a second set of values.

68. The method according to claim 67, wherein the first and second sets of values are non-overlapping.

59. (canceled)

69-74. -74. (canceled)

75. A method for surgically implanting an electrode device in a vicinity of a nerve, comprising:

placing the electrode device around the nerve;

introducing conductive solution into the electrode device such that the solution is in contact with both the electrode device and the nerve;

during implantation of the electrode device, measuring an impedance between one or more electrodes of the electrode device and an electrical contact point in electrical communication with the electrode device; and

responsively to the impedance measurement, determining whether the electrodes are positioned appropriately, and whether sufficient conductive solution is in the electrode device.

76. The method according to claim 75, wherein the conductive solution includes saline solution, and wherein introducing the conductive solution comprises introducing the saline solution.

77. The method according to claim 75, wherein the nerve includes a vagus nerve, and wherein placing the electrode device around the nerve comprises placing the electrode device around the vagus nerve.

78. The method according to claim 75, comprising, responsively to the impedance measurement, determining whether the electrodes are correctly sized for the nerve.

79. The method according to claim 75, wherein determining whether the electrodes are positioned appropriately comprises determining whether the electrodes are in good electrical contact with the nerve.

80. The method according to claim 75, wherein determining whether the electrodes are positioned appropriately comprises interpreting a value of the impedance measurement between 100 and 300 ohms as an indication that the electrodes are not positioned appropriately.

81. The method according to claim 75, wherein determining whether the electrodes are positioned appropriately comprises interpreting a value of the impedance measurement between 300 and 1000 ohms as an indication that the electrodes are positioned appropriately.

82. The method according to claim 75, wherein determining whether sufficient conductive solution is in the electrode device comprises interpreting a value of the impedance measurement greater than 1000 ohms as an indication that insufficient conductive solution is in the electrode device.

83. The method according to claim 75, wherein the one or more electrodes of the electrode device include at least first and second electrodes, wherein the electrical contact point includes the first one of the electrodes, and wherein measuring the impedance comprises measuring the impedance between the first and second electrodes.

84. The method according to claim 75, wherein the electrical contact point is located outside of the electrode device, and wherein measuring the impedance comprises measuring the impedance between the one or more electrodes and the electrical contact point located outside of the electrode device.

85. A method comprising:

sensing, from within a body of a subject, a physiological parameter of a heart of the subject;

detecting a life-threatening arrhythmia (LTA) responsively to the sensed physiological parameter;

responsively to the detection of the LTA, applying to a site of the subject a current that increases parasympathetic tone of the subject, the site selected from the list consisting of;

a vagus nerve of the subject, an epicardial fat pad of the subject, a pulmonary vein of the subject, a carotid artery of the subject, a carotid sinus of the subject, a coronary sinus of the subject, a vena cava vein of the subject, a right ventricle of the subject, and a jugular vein of the subject;

determining whether the LTA has been resolved;

responsively to a determination that the LTA has not been resolved, determining whether to apply, from within the body, pulses to the heart selected from the list consisting of;

pacing pulses and anti-arrhythmic energy;

responsively to an affirmative determination to apply the pulses, applying the pulses to the heart; and

responsively to a determination not to apply the pulses, applying the current to the site.

86. The method according to claim 85, comprising changing a parameter of the current applied to the site, after the determination not to apply the pulses.

87. The method according to claim 85, wherein the pulses include anti-arrhythmic energy.

88. The method according to claim 85, wherein the pulses include pacing pulses.

89. The method according to claim 85, wherein the parameter includes a feature of an electrocardiogram (ECG) signal, and wherein sensing comprises sensing the feature.

90. The method according to claim 85, wherein determining comprises determining to apply the pulses only if applying the current is determined to be unlikely to resolve the LTA.

91. A method comprising:

applying to a site of a subject a current that increases parasympathetic tone of the subject, the site selected from the list consisting of;

a vagus nerve of the subject, an epicardial fat pad of the subject, a pulmonary vein of the subject, a carotid artery of the subject, a carotid sinus of the subject, a coronary sinus of the subject, a vena cava vein of the subject, a right ventricle of the subject, and a jugular vein of the subject;

sensing, from within a body of the subject, a physiological parameter of a heart of the subject;

detecting a life-threatening arrhythmia (LTA) responsively to the sensed physiological parameter;

responsively to the detection of the LTA, modifying at least one current parameter of the applied current;

determining whether the LTA has been resolved;

responsively to a determination that the LTA has not been resolved, determining whether to apply, from within the body, pulses to the heart selected from the list consisting of;

pacing pulses and anti-arrhythmic energy;

responsively to an affirmative determination to apply the pulses, applying the pulses to the heart; and

responsively to a determination not to apply the pulses, modifying one or more current parameters of the applied current.

92. The method according to claim 91, wherein the pulses include anti-arrhythmic energy.

93. The method according to claim 91, wherein the pulses include pacing pulses.

94. The method according to claim 91, wherein the parameter includes a feature of an electrocardiogram (ECG) signal, and wherein sensing comprises sensing the feature.

95. The method according to claim 91, wherein determining comprises determining to apply the pulses only if applying the current is determined to be unlikely to resolve the LTA.