Rate Adaptive Cardiac Pacing Systems and Methods

• US 20080154139A1
• Filed: 12/20/2006
• Published: 06/26/2008
• Est. Priority Date: 12/20/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Shuros, Allan C., Hopper, Donald L., Kane, Michael J.
• Granted Patent: US 8,406,879 B2
• Time in Patent Office: Days
• US Class Current: 600/481
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: G16H 20/40 relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
• CPC Class Codes: G16H 40/67 for remote operation

Abstract

The invention relates to cardiac rhythm management systems, and more particularly, to rate adaptive cardiac pacing systems and methods. In an embodiment, the invention includes a method for providing rate-adaptive cardiac pacing therapy from an implantable medical device, the method including sensing a pulmonary function of a patient; determining a rate of change in the pulmonary function; sensing a cardiac function of the patient; determining a rate of change in the cardiac function; and calculating a target pacing rate based on an existing pacing rate, the rate of change in the pulmonary function, and the rate of change in the cardiac function. In an embodiment, the invention includes a method of controlling a cardiac rhythm management device in response to exertion of a patient, the method including sensing the patient'"'"'s pulmonary function at a first time t₁ and at a second time t₂; calculating a rate of change of the pulmonary function between time t₁ and time t₂; sensing the patient'"'"'s cardiac function at time t₃ and t₄; calculating a rate of change of the cardiac function between time t₃ and time t₄; and setting a desired pacing rate. Embodiments of the invention also include cardiac rhythm management devices.

Claims

1. A method for providing rate-adaptive cardiac pacing therapy from an implantable medical device, the method comprising:

sensing a pulmonary function of a patient;

determining a rate of change in the pulmonary function;

sensing a cardiac function of the patient;

determining a rate of change in the cardiac function; and

calculating a target pacing rate based on an existing pacing rate, the rate of change in the pulmonary function, and the rate of change in the cardiac function.

2. The method of claim 1, wherein sensing the pulmonary function comprises sensing a parameter that correlates to pulmonary function, the parameter selected from the group consisting of respiratory frequency, tidal volume, and minute ventilation.

3. The method of claim 1, wherein sensing the cardiac function comprises sensing a parameter that correlates to cardiac function.

4. The method of claim 3, the parameter that correlates to cardiac function comprising a hemodynamic parameter.

5. The method of claim 4, the hemodynamic parameter selected from the group consisting of stroke volume, cardiac output, heart sounds, and cardiac contractility.

6. The method of claim 1, further comprising delivering cardiac pacing therapy at the target pacing rate.

7. The method of claim 1, wherein calculating the target pacing rate comprises making the target pacing rate faster than the existing pacing rate when the pulmonary function is increasing with time and the cardiac function is increasing with time.

8. The method of claim 1, wherein calculating the target pacing rate comprises making the target pacing rate equal to the existing pacing rate when the pulmonary function is increasing with time and the cardiac function is not increasing with time.

9. The method of claim 1, wherein calculating the target pacing rate comprises making the adapted pacing rate less than the existing pacing rate when the pulmonary function is decreasing with time.

10. The method of claim 1, wherein sensing the pulmonary function and sensing the cardiac function are both performed by a single sensor.

11. The method of claim 1, wherein the steps of sensing the pulmonary function and sensing the cardiac function are performed by separate sensors.

12. The method of claim 1, wherein sensing pulmonary function and/or sensing cardiac function comprise sensing a change in the curvature of an optical conductor.

13. The method of claim 1, wherein sensing pulmonary function and/or sensing cardiac function comprise sensing a change in pressure.

14. The method of claim 1, wherein sensing pulmonary function and/or sensing cardiac function comprise sensing a flow rate of a fluid.

15. The method of claim 1, wherein sensing pulmonary function and/or sensing cardiac function comprise sensing impedance across a tissue of the patient.

16. A method of controlling a cardiac rhythm management device in response to exertion of a patient, the method comprising:

sensing the patient'"'"'s pulmonary function at a first time t₁ and at a second time t₂;

calculating a rate of change of the pulmonary function between time t₁ and time t₂;

sensing the patient'"'"'s cardiac function at a third time t₃ and a fourth time t₄;

calculating a rate of change of the cardiac function between time t₃ and time t₄; and

setting a desired pacing rate by increasing an existing pacing rate proportionately to the rate of change of the pulmonary function when the rate of change of the pulmonary function is positive and the rate of change of cardiac function is not negative.

17. The method of claim 16, wherein the difference between time t₁ and time t₂, and the difference between time t₃ and time t₄, is greater than about one second and less than about one minute.

18. The method of claim 16, wherein sensing the patient'"'"'s pulmonary function comprises sensing minute ventilation.

19. The method of claim 16, wherein sensing the patient'"'"'s cardiac function comprises sensing stroke volume.

20. The method of claim 16, wherein time t₁ and time t₃ occur at the same point in time, and time t₂ and time t₄ occur at the same point in time.

21. A cardiac rhythm management device comprising:

a pulse generator for generating electrical pulses to be delivered to a heart at a pacing rate;

a processor in communication with the pulse generator;

one or more sensors for sensing pulmonary function and cardiac function, the one or more sensors in communication with the processor; and

the processor configured to increase the pacing rate if the pulmonary function is increasing with time and the cardiac function is not decreasing with time;

maintain the pacing rate if the pulmonary function is increasing with time and the cardiac function is decreasing with time; and

decrease the pacing rate if the respiratory function is decreasing with time.

22. The cardiac rhythm management device of claim 21, the one or more sensors comprising a single sensor sensing both pulmonary function and cardiac function.

23. The cardiac rhythm management device of claim 21, the one or more sensors comprising a first sensor for sensing pulmonary function and a second sensor for sensing cardiac function.

24. The cardiac rhythm management device of claim 21, pulmonary function comprising minute ventilation.

25. The cardiac rhythm management device of claim 21, cardiac function comprising stroke volume.