Method and apparatus for improving ventricular status using the force interval relationship

• US 20040220639A1
• Filed: 04/30/2003
• Published: 11/04/2004
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Hill, Michael R.S., Mulligan, Lawrence J., Burnes, John E.
• Granted Patent: US 7,130,684 B2
• Time in Patent Office: Days
• US Class Current: 607/28
• 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 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585

Abstract

Methods and devices for improving ventricular contractile status of a patient suitably exploit changes in ventricular pressure and/or dP/dt_max to provide and/or optimize a response to a patient. The ventricular pressure may be appropriately correlated to intracellular calcium regulation, which is indicative of contractile status. To assess ventricular contractile status, the device suitably observes a cardiac perturbation of the patient and measures force interval potentiation following the perturbation. The contractile potentiation can then be stored and/or quantified in the implantable medical device to determine the ventricular contractile status of the patient, and an appropriate response may be provided to the patient as a function of the ventricular contractile status. Examples of responses may include administration of drug or neuro therapies, modification of a pacing rate, or the like. Force interval potentiation may also be used to optimize or improve a parameter for a response provided by the implantable medical device.

Claims

1. A method of improving a ventricular contractile status of a patient with an implantable medical device, the method comprising the steps of:

observing a cardiac perturbation of the patient at the implantable medical device;

measuring heart beat potentiation following the perturbation at the implantable medical device;

quantifying the heart beat potentiation to determine the ventricular contractile status of the patient at the implantable medical device; and

providing a response from the implantable medical device to the patient as a function of the ventricular contractile status.

2. The method of claim 1 wherein the identifying step comprises inducing the perturbation in the patient from the implantable medical device.

3. The method of claim 2 wherein the cardiac perturbation is a premature ventricular contraction.

4. The method of claim 2 wherein the cardiac perturbation is an extra-systolic beat.

5. The method of claim 2 wherein the cardiac perturbation comprises a change in heart rate.

6. The method of claim 2 wherein the cardiac perturbation comprises a change in hemodynamic pressure.

7. The method of claim 1 wherein the quantifying step comprises calculating a recirculation fraction as a function of the heart beat potentiation.

8. The method of claim 1 wherein the quantifying step comprises calculating a potentiation ratio as a function of the heart beat potentiation.

9. The method of claim 1 wherein the quantifying step comprises calculating a potentiation ratio and a recirculation fraction as a function of the heart beat potentiation.

10. The method of claim 1 wherein the response comprises providing a medication.

11. The method of claim 1 wherein the response comprises providing an electrical signal to the heart.

12. The method of claim 1 wherein the response comprises neurological stimulation.

13. The method of claim 1 wherein the response comprises adjusting a timing parameter.

14. The method of claim 1 wherein the response comprises storing data about the hemodynamic status in the implantable medical device.

15. The method of claim 1 further comprising the steps of gathering feedback data about the heart as the response is provided, and adjusting the response as a function of the feedback data.

16. The method of claim 15 wherein the response comprises providing a medication.

17. The method of claim 15 wherein the response comprises adjusting a timing parameter.

18. A method of improving a ventricular contractile status of a patient with an implantable medical device, the method comprising the steps of:

producing an extra-systolic beat from the implantable medical device;

measuring potentiation in a ventricular force interval following the extra-systolic beat at the implantable medical device;

quantifying the potentiation to determine the ventricular contractile status of the patient at the implantable medical device; and

adjusting a parameter of a stimulus provided by the implantable medical device to the patient as a function of the ventricular contractile status.

19. A medical device configured to be implanted in a patient, the device comprising:

a data collection module configured to identify contractile potentiation in the patient following a cardiac perturbation;

a data processing module in communication with the data collection module, wherein the data processing module is configured to correlate the potentiation to a hemodynamic status of the patient; and

a response module in communication with the data processing module, wherein the response module is configured to provide a response based upon the hemodynamic status.

20. The device of claim 19 further comprising a digital memory in communication with the data processing module, and wherein the response comprises storing historical data about the hemodynamic status in the memory.

21. The device of claim 19 wherein the response module comprises an interface to at least one pacing electrode.

22. The device of claim 21 wherein the data processing module is further configured to induce the perturbation in the patient using the at least one pacing electrode.

23. The device of claim 19 wherein the data processing module is further configured to adjust the response as a function of the reaction.

24. The device of claim 23 wherein the response comprises administering a drug therapy.

25. The device of claim 23 wherein the response comprises adjusting a pacing parameter.

26. A medical device implanted in a patient, the method comprising the steps of:

means for observing a cardiac perturbation of the patient;

means for measuring potentiation in ventricular force resulting from the cardiac perturbation;

means for quantifying the potentiation to determine a hemodynamic status of the patient; and

means for providing a response to the patient as a function of the hemodynamic status.

27. The medical device of claim 26 further comprising means for inducing the cardiac perturbation in the patient from the implantable medical device.

28. A method of calibrating a parameter using an implantable medical device, the method comprising the steps of:

providing a cardiac perturbation to a patient from the implantable medical device using an initial value of the parameter;

observing potentiation in the patient as a result of the cardiac perturbation;

adjusting a value of the parameter in response to the potentiation observed; and

repeating the adjusting and observing steps until a maximum amount of potentiation is observed in the patient.

29. The method of claim 28 further comprising the step of setting an optimal value for the parameter, wherein the optimal value corresponds to the value used to generate the maximum amount of potentiation.

30. The method of claim 28 wherein the parameter is a pacing interval.

31. The method of claim 30 wherein the pacing interval is an AV pacing interval.

32. The method of claim 30 wherein the pacing interval is a VV pacing interval.

33. The method of claim 29 wherein the parameter is a drug therapy.

34. The method of claim 29 wherein the parameter is a neurotherapy.

35. The method of claim 28 wherein the cardiac perturbation comprises a premature ventricular contraction.

36. The method of claim 28 wherein the cardiac perturbation comprises a change in hemodynamic pressure.

37. The method of claim 28 wherein the cardiac perturbation comprises an extra-systolic beat.