Therapy using perturbation and effect of physiological systems

1. A device for use in treatment of a patient comprising:

perturbation apparatus configured to perturb at least one physiological system of a patient, wherein the perturbation apparatus comprises at least one electrode to stimulate an efferent fiber of a vagus nerve;

monitoring apparatus configured to monitor physiological parameters of the patient, wherein the monitoring apparatus comprises at least one electrode to monitor an afferent fiber of the vagus nerve during delivery of electrical stimulation to the efferent fiber;

a sensing module coupled to the monitoring apparatus and configured to receive the monitored physiological parameters;

a therapy delivery module configured to deliver therapy to the patient; and

a control module coupled to the perturbation apparatus, to the sensing module, and to the therapy delivery module, and configured to:

perturb at least one physiological system of the patient using the perturbation apparatus by at least delivering electrical stimulation to the efferent fiber,

monitor electrical activity from the afferent nerve, wherein the electrical activity includes an indirect component of a compound action potential (CAP), wherein the afferent electrical activity is associated with a burst pattern during a predetermined phase of a cardiac cycle,

assess a status of the patient's heart based on the indirect component, and

determine whether to deliver therapy to the patient using the therapy delivery module based on the assessed status of the patient's heart.

2. The device of claim 1 , wherein the control module is configured to monitor one of a latency and a dispersion of the indirect component.

3. The device of claim 2 , wherein the monitored latency or monitored dispersion indicates an unhealthy cardiac condition.

4. The device of claim 2 , wherein the monitored dispersion is compared to an expected time constant of dispersion to assess the status of the patient's heart.

5. The device of claim 4 , wherein the expected time constant of dispersion correlates to a time constant of an initial change in a cardiac parameter.

6. The device of claim 2 , wherein the monitored latency is compared to a time constant of latency to assess the status of the patient's heart.

7. The device of claim 1 , wherein the indirect component has a high velocity.

8. The device of claim 1 , wherein the electrical stimulation is equal to or less than 5 milliamperes.

9. The device of claim 1 , wherein the electrical stimulation is about 3 milliamperes.

10. The device of claim 1 , wherein determining whether to deliver therapy is based upon comparing the monitored afferent electrical activity to a baseline level.

11. The device of claim 1 , wherein delivery of electrical stimulation is adjusted by adjusting a pacing parameter.

12. The device of claim 11 , wherein the pacing parameter is one of AV timing, VV timing, and rate.

13. A method for using an implantable medical device, the method comprising:

delivering electrical stimuli to an efferent nerve associated with a selected organ, wherein delivery of electrical stimuli is adjusted by adjusting a pacing parameter;

monitoring afferent electrical activity during delivery of electrical stimuli to the efferent nerve, the monitored afferent electrical activity includes an indirect component of a compound action potential (CAP);

assessing a status of the selected organ based upon the indirect component; and

determining whether to deliver therapy to the selected organ in response to assessing the status of the selected organ.

14. The method of claim 13 , wherein monitoring afferent electrical activity comprises monitoring at least one of a dispersion and a latency of the indirect component.

15. The method of claim 14 , wherein the monitored latency of the indirect component of the afferent electrical activity indicates an unhealthy cardiac condition.

16. The method of claim 14 , wherein the monitored dispersion of the indirect component of the afferent electrical activity indicates an unhealthy cardiac condition.

17. The method of claim 14 , wherein the monitored dispersion is compared to an expected time constant of dispersion to assessing the status of the selected organ.

18. The method of claim 17 , wherein the expected time constant of dispersion correlates to a time constant of an initial change in a cardiac parameter.

19. The method of claim 14 , wherein the monitored latency is compared to a time constant of latency to assessing the status of the selected organ.

20. The method of claim 13 , wherein determining whether to deliver therapy is based upon comparing the monitored afferent electrical activity to a baseline level.

21. The method of claim 13 , wherein the selected organ is one of a heart and a baroreceptor reflex.

22. The method of claim 13 , wherein the monitored afferent electrical activity is in response to a burst pattern of electrical stimuli during a predetermined phase of a cardiac cycle.

23. The method of claim 13 , wherein the pacing parameter is one of AV timing, VV timing, and rate.

24. The method of claim 13 , wherein delivery of electrical stimuli is further adjusted by adjusting at least one of amplitude of the electrical stimuli and frequency of the electrical stimuli.

25. The method of claim 13 , wherein assessing the status of the selected organ is based on a phase of a patient's heart.

26. A method for using an implantable medical device, the method comprising:

introducing a perturbation, wherein the perturbation includes electrical stimulation, and wherein the electrical stimulation is adjusted to change one of AV timing and VV timing;

monitoring afferent electrical activity;

assessing a status of the selected organ; and

determining whether to deliver therapy to the selected organ in response to assessing the status of the selected organ.

27. The method of claim 26 , wherein the perturbation further includes a drug.

28. The method of claim 26 , wherein the electrical stimulation is adjusted by adjusting at least one of a frequency of the electrical stimulation, an amplitude of the electrical stimulation, and rate of delivery of the electrical stimulation.

29. The method of claim 26 , wherein the perturbation further includes a change in a position of a body.

30. The method of claim 26 , wherein assessing the status of the selected organ is based on a phase of heart.

31. The method of claim 26 , wherein the status of the selected organ is determined based upon one of an amplitude and a frequency of the afferent electrical activity.

32. The method of claim 26 , wherein an indirect component of the afferent electrical activity is used to assess the status of the selected organ.

33. A device for use in treatment of a patient comprising:

perturbation apparatus configured to perturb at least one physiological system of a patient, wherein the perturbation apparatus comprises at least one electrode to stimulate an efferent fiber of a vagus nerve;

monitoring apparatus configured to monitor physiological parameters of the patient, wherein the monitoring apparatus comprises at least one electrode to monitor an afferent fiber of the vagus nerve during delivery of electrical stimulation to the efferent fiber;

a sensing module coupled to the monitoring apparatus and configured to receive the monitored physiological parameters;

a therapy delivery module configured to deliver therapy to the patient; and

a control module coupled to the perturbation apparatus, to the sensing module, and to the therapy delivery module, and configured to:

perturb at least one physiological system of the patient using the perturbation apparatus by at least delivering electrical stimulation to the efferent fiber, wherein the electrical stimulation is about 3 milliamperes,

monitor electrical activity from the afferent nerve, wherein the electrical activity includes an indirect component of a compound action potential (CAP),

assess a status of the patient's heart based on the indirect component, and

determine whether to deliver therapy to the patient using the therapy delivery module based on the assessed status of the patient's heart.

34. The device of claim 33 , wherein the control module is configured to monitor at least one of a latency and a dispersion of the indirect component.

35. The device of claim 34 , wherein at least one of the latency and the dispersion of the indirect component indicates an unhealthy cardiac condition.

36. The device of claim 33 , wherein assessing the status of the patient's heart comprises comparing the monitored afferent electrical activity to a baseline level.

37. A device for use in treatment of a patient comprising:

perturbation apparatus configured to perturb at least one physiological system of a patient, wherein the perturbation apparatus comprises at least one electrode to stimulate an efferent fiber of a vagus nerve;

monitoring apparatus configured to monitor physiological parameters of the patient, wherein the monitoring apparatus comprises at least one electrode to monitor an afferent fiber of the vagus nerve during delivery of electrical stimulation to the efferent fiber;

a sensing module coupled to the monitoring apparatus and configured to receive the monitored physiological parameters;

a therapy delivery module configured to deliver therapy to the patient; and

a control module coupled to the perturbation apparatus, to the sensing module, and to the therapy delivery module, and configured to:

perturb at least one physiological system of the patient using the perturbation apparatus by at least delivering electrical stimulation to the efferent fiber, wherein the delivery of electrical stimulation is adjusted by adjusting a pacing parameter,

monitor electrical activity from the afferent nerve, wherein the electrical activity includes an indirect component of a compound action potential (CAP),

assess a status of the patient's heart based on the indirect component, and

determine whether to deliver therapy to the patient using the therapy delivery module based on the assessed status of the patient's heart.

38. The device of claim 37 , wherein the control module is configured to monitor at least one of a latency and a dispersion of the indirect component.

39. The device of claim 38 , wherein at least one of the latency and the dispersion of the indirect component indicates an unhealthy cardiac condition.

40. The device of claim 38 , wherein assessing a status of the patient's heart comprises comparing the monitored afferent electrical activity to a baseline level.

41. The device of claim 37 , wherein the pacing parameter is one of AV timing, VV timing, and rate.

42. A method for using an implantable medical device, the method comprising:

delivering electrical stimuli to an efferent nerve associated with a selected organ, wherein the selected organ comprises one of a kidney, a stomach, and a gastrointestinal tract;

monitoring afferent electrical activity during delivery of electrical stimuli to the efferent nerve, the monitored afferent electrical activity includes an indirect component of a compound action potential (CAP);

assessing a status of the selected organ based upon the indirect component; and

determining whether to deliver therapy to the selected organ in response to assessing the status of the selected organ.

43. The method of claim 42 , wherein the monitored afferent electrical activity comprises at least one of a dispersion and a latency of the indirect component.

44. The method of claim 43 , wherein the latency of the indirect component indicates an unhealthy condition of the selected organ.

45. The method of claim 43 , wherein the dispersion of the indirect component indicates an unhealthy condition of the selected organ.

46. A method for using an implantable medical device, the method comprising:

delivering electrical stimuli to an efferent nerve associated with a selected organ;

monitoring afferent electrical activity during delivery of electrical stimuli to the efferent nerve, the monitored afferent electrical activity includes an indirect component of a compound action potential (CAP), wherein the afferent electrical activity is in response to a burst pattern of electrical stimuli during a predetermined phase of a cardiac cycle;

assessing a status of the selected organ based upon the indirect component; and

determining whether to deliver therapy to the selected organ in response to assessing the status of the selected organ.

47. The method of claim 46 , wherein the monitored afferent electrical activity comprises at least one of a dispersion and a latency of the indirect component.

48. The method of claim 47 , wherein the latency of the indirect component indicates an unhealthy cardiac condition.

49. The method of claim 47 , wherein the dispersion of the indirect component indicates an unhealthy cardiac condition.