Detection of orthostatic hypotension using positional data and cross-check data

• US 6,738,666 B1
• Filed: 11/01/2001
• Issued: 05/18/2004
• Est. Priority Date: 11/01/2001
• Status: Expired due to Fees

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Bradley, Kerry, Park, Euljoon
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US10/002,615
• Time in Patent Office: 929 Days
• Field of Search: 607/17, 607/18, 607/19, 607/20, 607/21, 607/22, 607/23, 607/24, 607/9, 607/2, 607/14, 607/27
• US Class Current: 607/18
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration

Abstract

An implantable cardiac stimulation device is programmed to administer pacing therapy in response to a postural change in a patient'"'"'s position and a confirmation of that postural change using a cross-check parameter. The stimulation device is equipped with a position sensor to sense a position parameter indicative of when a patient changes from a horizontal position to an upright position. The stimulation device further monitors a cross-check parameter that is affected or modulated by position changes. When the position sensor indicates a postural change and the cross-check parameter confirms this change as being sufficient to induce orthostatic hypotension, the device administers cardiac pacing therapy to the patient.

Claims

1. A method comprising:

determining a position parameter indicative of a change in a patient'"'"'s position;

determining a cross-check parameter affected at least in part by the change in the patient'"'"'s position; and

selectively administering pacing therapy to the patient based on the position parameter and the cross-check parameter.

2. The method of claim 1, wherein the determining a position parameter comprises:

monitoring position data generated by a position sensor; and

detecting, from the position data, a change in the patient'"'"'s position from a horizontal position to an upright position.

3. The method of claim 2, wherein the detecting comprises detecting the change in the patient'"'"'s position for a specified period of time.

4. The method of claim 1, wherein the determining a cross-check parameter comprises detecting changes in an evoked response amplitude.

5. The method of claim 1, wherein the determining a cross-check parameter is selected from a group of parameters comprising stroke volume, a cardiac impedance parameter, evoked response integral, ventricular wall thickness, ventricular pressure, atrial evoked response amplitude, and atrial evoked response integral.

6. The method of claim 1, wherein the determining a cross-check parameter comprises:

monitoring an evoked response parameter (ERP) functionally related to an evoked response amplitude (ERA);

computing a delta ERP (Δ

ERP) as a function of the ERP and a moving average of the ERP; and

evaluating the Δ

ERP computed at approximately a time when the position parameter indicates the change in the patient'"'"'s position.

7. The method of claim 6, wherein the determining a cross-check parameter further comprises confirming the change in patient'"'"'s position in response to significant change in the Δ

ERP.

8. The method of claim 1, wherein the administering comprises increasing a cardiac pacing rate from a first pacing rate to a higher second pacing rate.

9. The method of claim 1, wherein the administering comprises administering a pacing therapy effective to counteract effects of orthostatic hypotension.

10. The method of claim 1, further comprising systematically removing the pacing therapy after a predetermined amount of time.

11. The method of claim 1, wherein the cross-check parameter comprises a first cross-check parameter and further comprising:

determining a second cross-check parameter affected at least in part by the change in the patient'"'"'s position; and

selectively administering pacing therapy to the patient based on the position parameter, the first cross-check parameter, and a second cross-check parameter.

12. One or more computer-readable media having computer-readable instructions thereon which, when executed by a programmable stimulation device, cause the stimulation device to execute the method of claim 1.

13. A method of administering pacing therapy for orthostatic hypotension, comprising:

detecting a postural change in a patient from a horizontal position to an upright position;

confirming the postural change using a cross-check parameter; and

adjusting a cardiac pacing rate from a first pacing rate to a second pacing rate effective to counteract effects of orthostatic hypotension in response to detection of the postural change in the patient'"'"'s position and confirmation of the postural change via the cross-check parameter.

14. The method of claim 13, wherein the detecting comprises:

monitoring positional data generated by a 3D accelerometer; and

detecting, from the positional data, the change from the horizontal position to the upright position.

15. The method of claim 13, wherein the detecting comprises detecting the change for a specified period of time.

16. The method of claim 13, wherein the confirming comprises detecting changes in an evoked response amplitude.

17. The method of claim 13, wherein the determining a cross-check parameter is selected from a group of parameters comprising stroke volume, a cardiac impedance parameter, evoked response integral, ventricular wall thickness, ventricular pressure, atrial evoked response amplitude, and atrial evoked response integral.

18. The method of claim 13, wherein the confirming comprises:

monitoring an evoked response parameter (ERP) functionally related to an evoked response amplitude (ERA);

computing a delta ERP (Δ

ERP) as a function of the ERP and a moving average of the ERP; and

evaluating the Δ

ERP computed at approximately a time when the position parameter indicates the change in the patient'"'"'s position.

19. The method of claim 13, further comprising adjusting the cardiac pacing rate back toward the first pacing rate.

20. The method of claim 13, further comprising adjusting the cardiac pacing rate back toward the first pacing rate after a predetermined amount of time.

21. One or more computer-readable media having computer-readable instructions thereon which, when executed by a programmable stimulation device, cause the stimulation device to execute the method of claim 13.

22. A method comprising:

detecting a postural change in a patient;

evaluating an evoked response parameter functionally related to an evoked response amplitude for an indication of the postural change; and

applying cardiac pacing therapy in response to detection of the postural change that is additionally confirmed by the evoked response parameter.

23. The method of claim 22, wherein the evaluating comprises:

monitoring the evoked response parameter (ERP);

computing a delta ERP (Δ

ERP) as a function of the ERP and a moving average of the ERP;

examining the Δ

ERP computed at approximately at time when the postural change is detected; and

in an event that the Δ

ERP changes by a predetermined amount, confirming that the postural change did occur.

24. One or more computer-readable media having computer-readable instructions thereon which, when executed by a programmable stimulation device, cause the stimulation device to execute the method of claim 22.

25. A method comprising:

increasing a pacing rate in a cardiac stimulation device from a first rate to a higher second rate upon (1) detection of a change in patient'"'"'s position and (2) confirmation of the change using a non-position parameter; and

subsequently decreasing the pacing rate back toward the first rate.

26. The method of claim 25, wherein the non-position parameter is selected from a group of parameters comprising stroke volume, a cardiac impedance parameter, evoked response integral, ventricular wall thickness, ventricular pressure, atrial evoked response amplitude, and atrial evoked response integral.

27. The method of claim 25, further comprising decreasing the pacing rate after a predetermined period of time.

28. One or more computer-readable media having computer-readable instructions thereon which, when executed by a programmable stimulation device, cause the stimulation device to execute the method of claim 25.

29. A cardiac stimulation device comprising:

a position sensor to sense a position parameter indicative of changes in a patient'"'"'s position;

a processor operably coupled to the position sensor, the processor being configured to determine when to administer cardiac pacing therapy to the patient based on the position parameter and a second cross-check parameter that is affected by the change in the patient'"'"'s position and is used to confirm a position change sensed by the position sensor; and

a pacing generator configured to administer the cardiac pacing therapy as directed by the processor.

30. The cardiac stimulation device of claim 29, wherein the position sensor comprises a 3D accelerometer.

31. The cardiac stimulation device of claim 29, wherein the position sensor is configured to sense a change from a horizontal position to an upright position.

32. The cardiac stimulation device of claim 29, wherein the cross-check parameter comprises a ventricular evoked response amplitude.

33. The cardiac stimulation device of claim 29, wherein the cross-check parameter comprises a cross-check parameter is selected from a group of parameters comprising stroke volume, a cardiac impedance parameter, evoked response integral, ventricular wall thickness, ventricular pressure, atrial evoked response amplitude, and atrial evoked response integral.

34. The cardiac stimulation device of claim 29, wherein the processor determines to administer cardiac pacing therapy when the position sensor detects a postural change from a horizontal position to an upright position and the cross-check parameter confirms the postural change.

35. The cardiac stimulation device of claim 34, wherein the pacing generator increases a pacing rate from a first rate to a higher second rate.

36. The cardiac stimulation device of claim 34, wherein the pacing generator generates a pacing rate effective to counteract effects of orthostatic hypotension.

37. The cardiac stimulation device of claim 34, wherein the pacing generator administers the cardiac pacing therapy for a predetermined period of time.

38. An implantable cardiac rhythm management device, comprising:

position sensing means for sensing a change in a patient'"'"'s position from a horizontal position to an upright position;

evaluation means for evaluating a cross-check parameter affected by the change in the patient'"'"'s position; and

therapy delivery means, responsive to the position sensing means and the evaluation means, for generating cardiac stimulating pulses at an increased rate effective to treat orthostatic hypotension when the position sensing means senses a postural change from a horizontal position to an upright position and the evaluation means confirms the postural change.

39. The implantable cardiac rhythm management device of claim 38, wherein the evaluation means comprises detecting means for detecting changes in an evoked response amplitude.

40. The implantable cardiac rhythm management device of claim 38, wherein the therapy delivery means systematically reduces the pulse rate following treatment of the orthostatic hypotension.

41. A programmable cardiac stimulation device having a memory and a processor, the cardiac stimulation device being programmed to perform tasks comprising:

administering pacing therapy to a patient when the device (1) detects a postural change from a horizontal position to an upright position and (2) confirms the postural change using a cross-check parameter; and

subsequently removing the pacing therapy in a systematic manner.

42. The programmable cardiac stimulation device of claim 41, wherein the cross-check parameter comprises an evoked response amplitude.

43. The programmable cardiac stimulation device of claim 41, wherein the cross-check parameter comprises a cross-check parameter is selected from a group of parameters comprising stroke volume, a cardiac impedance parameter, evoked response integral, ventricular wall thickness, ventricular pressure, atrial evoked response amplitude, and atrial evoked response integral.

44. The programmable cardiac stimulation device of claim 41, wherein the cardiac stimulation device is programmed to perform additional tasks comprising:

monitoring an evoked response parameter (ERP) functionally related to an evoked response amplitude (ERA);

computing a delta ERP (Δ

ERP) as a function of the ERP and a moving average of the ERP;

examining the Δ

ERP computed at approximately at time when the postural change is detected; and

in an event that the Δ

ERP changes by a predetermined amount, confirming that the postural change did occur.