Method and apparatus for rate responsive adjustments in an implantable medical device

• US 20030204211A1
• Filed: 04/29/2002
• Published: 10/30/2003
• Est. Priority Date: 04/29/2002
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Condie, Catherine R., Wahlstrand, John D., Mongeon, Luc R., Cho, Yong Kyun, Brandstetter, John S., Portzline, Gerald A.
• Granted Patent: US 7,031,772 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• 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 40/63 for local operation
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

A method and an apparatus for performing rate responsive control in an implantable medical device using a scaling factor. Sensor data is acquired using a sensor operatively coupled with the implantable medical device. At least one setpoint for controlling a rate of therapy is generated, the setpoint being based upon the sensor data. A scaling factor adjustment process is performed for scaling the internal sensor data to correlate the sensor data to the setpoint. The rate of therapy is adjusted based upon the scaling factor adjustment.

Claims

1. A method for performing rate responsive control in an implantable medical device, comprising:

acquiring an internal sensor data using an internal sensor operatively coupled with said implantable medical device;

generating at least one setpoint for controlling a rate of therapy, said setpoint based upon said internal sensor data;

performing a scaling factor adjustment process for scaling said internal sensor data to correlate said internal sensor data to said setpoint; and

adjusting said rate of therapy based upon said scaling factor adjustment.

2. The method described in claim 1, wherein acquiring said internal sensor data using said internal sensor further comprises acquiring minute ventilation (MV) data.

3. The method described in claim 1, wherein generating said setpoint for controlling said rate of therapy further comprises generating an activities of daily living (ADL) setpoint based upon an average daily rate.

4. The method described in claim 3, wherein generating said setpoint based upon an activities of daily living setpoint further comprises :

blending said internal data with an external data;

calculating a target pacing rate for a delivery of therapy based at least partially upon at least one of said blending of said internal and external data and an initial setpoint therapy target pacing rate;

modifying a therapy delivery rate based upon said target pacing rate; and

calculating a new setpoint therapy target pacing rate as feedback for calculating a subsequent target pacing rate.

5. The method described in claim 4, wherein blending said internal data with an external data further comprises blending said internal data with activity data.

6. The method described in claim 1, wherein performing said scaling factor adjustment process for scaling said internal sensor input to correlate said internal sensor data to said setpoint further comprises performing a scaling factor adjustment upon a minute ventilation (MV) data.

7. The method described in claim 1, wherein performing said scaling factor adjustment process further comprises:

performing a rate profile optimization (RPO) process to determine a rate profile;

generating an activities of daily living (ADL) setpoint based upon said RPO;

increasing said ADL setpoint based upon a determination that said ADL setpoint is below a lower boundary of an acceptable therapy rate;

setting an activity scaling factor to one in response to at least one of increasing said ADL setpoint and a determination that said ADL setpoint is within said lower boundary and an upper boundary of an acceptable therapy rate;

calculating a multiple of said ADL setpoint, in response to a determination that said ADL setpoint is above said upper boundary, said multiple being equal to a factor by which said ADL setpoint is above said upper boundary; and

adjusting said scaling factor to match said multiple.

8. The method described in claim 7, wherein performing said rate profile optimization process to determine a rate profile further comprises determining a rate for therapy delivery based upon at least one physiological profile of a patient.

9. The method described in claim 7, wherein generating an activities of daily living (ADL) setpoint based upon said RPO further comprises calculating an average therapy rate appropriate for a patient based upon at least one physiological profile of said patient.

10. The method described in claim 7, further comprising performing a time constant adjustment to said scaling factor, said time constant adjustment comprising calculating a time constant relating to interpolating an ADL setpoint value by tracking an average heart excursion.

11. A method for performing rate responsive control in an implantable medical device, comprising:

acquiring minute ventilation data using an internal sensor operatively coupled with said implantable medical device;

generating at least one activities of daily living (ADL) setpoint for controlling a rate of therapy, said ADL setpoint based upon said minute ventilation;

performing a scaling factor adjustment process for scaling said minute ventilation data to correlate said internal sensor data to said setpoint; and

adjusting said rate of therapy based upon said scaling factor adjustment.

12. The method described in claim 11, wherein performing said scaling factor adjustment process further comprises:

performing a rate profile optimization (RPO) process to determine a rate profile;

generating an activities of daily living (ADL) setpoint based upon said RPO;

increasing said ADL setpoint based upon a determination that said ADL setpoint is below a lower boundary of an acceptable therapy rate;

setting an activity scaling factor to one in response to at least one of increasing said ADL setpoint and a determination that said ADL setpoint is within said lower boundary and an upper boundary of an acceptable therapy rate;

calculating a multiple of said ADL setpoint, in response to a determination that said ADL setpoint is above said upper boundary, said multiple being equal to a factor by which said ADL setpoint is above said upper boundary; and

adjusting said scaling factor to match said multiple.

13. An apparatus for performing rate responsive control in an implantable medical device, comprising:

means for acquiring an internal sensor data using an internal sensor operatively coupled with said implantable medical device;

means for generating at least one setpoint for controlling a rate of therapy, said setpoint based upon said internal sensor data;

means for performing a scaling factor adjustment process for scaling said internal sensor data to correlate said internal sensor data to said setpoint; and

means for adjusting said rate of therapy based upon said scaling factor adjustment.

14. An implantable medical device, comprising:

a processor;

a control logic unit operatively coupled to said processor, said control logic generating at least one control signal in response to a command from said processor;

a data acquisition controller operatively coupled with said control logic unit, said data acquisition controller acquiring internal data in response to an assertion of at least one control signal from said control logic unit;

a memory unit operatively coupled with said data acquisition controller, said memory unit storing said acquired internal data; and

a firmware unit operatively coupled with at least one of said processor, said control unit, and said memory unit, said firmware unit calculating an activities of daily living (ADL) setpoint and performing a scaling factor adjustment process for scaling said internal data to correlate said internal sensor data to said ADL setpoint.

15. The apparatus of claim 14, wherein said firmware unit is a descriptive-language circuitry that can be programmed.

16. The apparatus of claim 14, wherein said firmware unit performing a scaling factor adjustment for scaling a minute ventilation signal to allow for a therapy rate to exceed said ADL setpoint.

17. The apparatus of claim 14, wherein said firmware unit further comprises:

means for acquiring an internal sensor data using an internal sensor operatively coupled with said implantable medical device;

means for generating at least one setpoint for controlling a rate of therapy, said setpoint based upon said internal sensor data;

means for performing a scaling factor adjustment process for scaling said internal sensor data to correlate said internal sensor data to said setpoint; and

means for adjusting said rate of therapy based upon said scaling factor adjustment.

18. A computer readable program storage device encoded with instructions that, when executed by a computer, performs a method, comprising:

acquiring an internal sensor data using an internal sensor operatively coupled with said implantable medical device;

generating at least one setpoint for controlling a rate of therapy, said setpoint based upon said internal sensor data;

performing a scaling factor adjustment process for scaling said internal sensor data to correlate said internal sensor data to said setpoint; and

adjusting said rate of therapy based upon said scaling factor adjustment.

19. The computer readable program storage device encoded with instructions that, when executed by a computer, performs the method described in claim 18, wherein acquiring said internal sensor data using said internal sensor further comprises acquiring minute ventilation (MV) data.

20. The computer readable program storage device encoded with instructions that, when executed by a computer, performs the method described in claim 18, wherein generating said setpoint for controlling said rate of therapy further comprises generating an activities of daily living (ADL) setpoint based upon an average daily rate.

21. The computer readable program storage device encoded with instructions that, when executed by a computer, performs the method described in claim 18, wherein generating said setpoint based upon an activities of daily living setpoint further comprises:

blending said internal data with an external data;

calculating a target pacing rate for a delivery of therapy based at least partially upon at least one of said blending of said internal and external data and an initial setpoint therapy target pacing rate;

modifying a therapy delivery rate based upon said target pacing rate; and

calculating a new setpoint therapy target pacing rate as feedback for calculating a subsequent target pacing rate.

22. The computer readable program storage device encoded with instructions that, when executed by a computer, performs the method described in claim 21, wherein blending said internal data with an external data further comprises blending said internal data with activity data.

23. The computer readable program storage device encoded with instructions that, when executed by a computer, performs the method described in claim 18, wherein performing said scaling factor adjustment process for scaling said internal sensor input to correlate said internal sensor data to said setpoint further comprises performing a scaling factor adjustment upon a minute ventilation (MV) data.

24. The computer readable program storage device encoded with instructions that, when executed by a computer, performs the method described in claim 18, wherein performing said scaling factor adjustment process further comprises:

performing a rate profile optimization (RPO) process to determine a rate profile;

generating an activities of daily living (ADL) setpoint based upon said RPO;

increasing said ADL setpoint based upon a determination that said ADL setpoint is below a lower boundary of an acceptable therapy rate;

setting an activity scaling factor to one in response to at least one of increasing said ADL setpoint and a determination that said ADL setpoint is within said lower boundary and an upper boundary of an acceptable therapy rate;

calculating a multiple of said ADL setpoint, in response to a determination that said ADL setpoint is above said upper boundary, said multiple being equal to a factor by which said ADL setpoint is above said upper boundary; and

adjusting said scaling factor to match said multiple.

25. The computer readable program storage device encoded with instructions that, when executed by a computer, performs the method described in claim 24, wherein performing said rate profile optimization process to determine a rate profile further comprises determining a rate for therapy delivery based upon at least one physiological profile of a patient.

26. The computer readable program storage device encoded with instructions that, when executed by a computer, performs the method described in claim 24, wherein generating an activities of daily living (ADL) setpoint based upon said RPO further comprises calculating an average therapy rate appropriate for patient based upon at least one physiological profile of said patient.

27. The computer readable program storage device encoded with instructions that, when executed by a computer, performs the method described in claim 24, the method further comprising performing a time constant adjustment to said scaling factor, said time constant adjustment comprising calculating a time constant relating to interpolating an ADL setpoint value by tracking an average heart excursion.