PHYSIOLOGICAL RESPONSE TO POSTURE CHANGE

• US 20120172764A1
• Filed: 03/08/2012
• Published: 07/05/2012
• Est. Priority Date: 08/24/2006
• Status: Active Grant

• Current Assignee: Aaron Lewicke, Imad Libbus, John D. Hatlestad
• Original Assignee: Aaron Lewicke, Imad Libbus, John D. Hatlestad
• Inventors: Hatlestad, John D., Libbus, Imad, Lewicke, Aaron
• Granted Patent: US 8,753,276 B2
• Time in Patent Office: Days
• US Class Current: 600/595
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence

Abstract

In an embodiment, an implantable medical device includes a controller circuit, a posture sensing circuit, and a physiological sensing circuit. The controller circuit senses a change in a physiological signal as a result of a change in posture, and generates a response as a function of that change. In another embodiment, the controller circuit identifies a heart failure condition as a function of the change in the physiological signal.

Claims

1. A method comprising:

using an implantable medical device to determine a change in a posture of a body;

determining a change in a physiological parameter in response to the change in posture, the physiological parameter including one or more of a heart rate, a heart rate variability, a heart sound, a respiration rate, and a blood pressure; and

generating a device response as a function of the change in the physiological parameter, wherein the change in the physiological parameter comprises at least one of;

a sensed change in heart rate that is less than a normal subject'"'"'s change in heart rate;

a sensed change in blood pressure that is more than a normal subject'"'"'s change in blood pressure;

a sensed change in heart sound energy that is less than a normal subject'"'"'s change in heart sound energy;

a sensed change in heart rate variability that is less than a normal subject'"'"'s change in heart rate variability; and

a sensed decrease in respiration rate.

2. The method of claim 1, further comprising comparing the change in the physiological parameter, the comparison comprising comparing (1) a ratio of the physiological parameter in a first posture to the physiological parameter in a second posture for a subject with a possible health condition, to (2) a ratio of the physiological parameter in a first posture to the physiological parameter in a second posture for a normal subject or population.

3. The method of claim 2,

wherein the ratio comprises 100*(RPP1/RPP2−

1),

wherein RPP1 relates to a resting physiological parameter while in a first posture, and

wherein RPP2 relates to a resting physiological parameter while in a second posture.

4. The method of claim 1, further comprising identifying at least one of a progression or a regression of a health condition of a subject as a function of the change in the physiological parameter.

5. The method of claim 4, including:

trending the physiological parameter, and

wherein identifying the health condition includes identifying one or more of a progression and a regression of heart failure status of the subject using the trending.

6. The method of claim 1, wherein generating the device response includes issuing an alert by the implantable medical device to an external device as a function of the change in the physiological parameter.

7. The method of claim 1, wherein generating the device response includes adjusting pacing therapy delivered using the implantable medical device.

8. The method of claim 1, wherein generating the device response includes adjusting neural stimulation therapy delivered using the implantable medical device.

9. The method of claim 1, wherein generating the device response includes adjusting delivery of a substance that is delivered by the implantable medical device.

10. The method of claim 9, including:

determining whether the body has changed from a recumbent posture to a posture that is more upright than recumbent, and

wherein adjusting delivery of a substance includes adjusting titration of a pharmaceutical in response to the determined change in posture.

11. The method of claim 1, including:

identifying a health condition associated with congestive heart failure as a function of the change in the physiological signal, and

wherein generating the response includes generating the response when the health condition is identified.

12. The method of claim 11, wherein identifying a health condition includes identifying an episode of congestive heart failure decompensation.

13. A method comprising:

using an implantable medical device to determine a change in a posture of a body;

determining a change in energy of a heart sound in response to the change in posture; and

generating a device response when determining that the sensed change in heart sound energy is less than a normal subject'"'"'s change in heart sound energy, wherein the response includes at least one of;

issuing an alert by the implantable medical device to an external device;

adjusting pacing therapy delivered using the implantable medical device;

adjusting neural stimulation therapy delivered using the implantable medical device; and

adjusting delivery of a substance that is delivered by the implantable medical device.

14. The method of claim 13,

wherein determining a change in posture includes determining a change from a recumbent posture to a posture more upright than recumbent, and

wherein determining a change in energy of a heart sound includes determining a change in energy of at least one of the S1 or S2 heart sounds that is less than a change in energy of the at least one S1 or S2 heart sounds for a normal subject.

15. A method comprising:

using an implantable medical device to determine a change in a posture of a body;

determining a change in a heart rate variability in response to the change in posture; and

generating a device response when the sensed change in heart rate variability is less than a normal subject'"'"'s change in heart rate variability, wherein the device response includes at least one of;

issuing an alert by the implantable medical device to an external device;

adjusting pacing therapy delivered using the implantable medical device;

adjusting neural stimulation therapy delivered using the implantable medical device; and

adjusting delivery of a substance that is delivered by the implantable medical device.

16. The method of claim 15,

wherein determining a change in posture includes determining a change from a supine position to a position more upright than supine, and

wherein determining a change in heart rate variability includes:

determining at least one higher frequency (HF) component of heart rate variability and at least one lower frequency (LF) component of heart rate variability; and

determining that a change in a ratio that includes LF and HF is less than a ratio change for a normal subject.

17. A method comprising:

using an implantable medical device to determine a change in a posture of a body;

determining a change in a respiration rate in response to the change in posture, and

generating a device response when determining a decrease in respiration rate, wherein the device response includes at least one of;

issuing an alert by the implantable medical device to an external device;

adjusting pacing therapy delivered using the implantable medical device;

adjusting neural stimulation therapy delivered using the implantable medical device; and

adjusting delivery of a substance that is delivered by the implantable medical device.

18. The method of claim 17, wherein the change in posture includes a change from a recumbent posture to a posture more upright than the recumbent posture.

19. A method comprising:

using an implantable medical device to determine a change in a posture of a body;

sensing a change in blood pressure in response to the change in posture; and

generating a device response when sensing change in blood pressure that is more than a normal subject'"'"'s change in blood pressure wherein the device response includes at least one of;

issuing an alert by the implantable medical device to an external device;

adjusting pacing therapy delivered using the implantable medical device;

adjusting neural stimulation therapy delivered using the implantable medical device; and

adjusting delivery of a substance that is delivered by the implantable medical device.

20. A method comprising:

using an implantable medical device to determine a change in a posture of a body;

sensing a change in heart rate in response to the change in posture; and

generating a device response when sensing a change in heart rate that is less than a normal subject'"'"'s change in heart rate, wherein the device response includes at least one of;

issuing an alert by the implantable medical device to an external device;

adjusting pacing therapy delivered using the implantable medical device;

adjusting neural stimulation therapy delivered using the implantable medical device; and

adjusting delivery of a substance that is delivered by the implantable medical device.