PHYSIOLOGICAL RESPONSE TO POSTURE CHANGE

• US 20080082001A1
• Filed: 08/24/2006
• Published: 04/03/2008
• Est. Priority Date: 08/24/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Hatlestad, John D., Libbus, Imad, Lewicke, Aaron
• Granted Patent: US 8,343,049 B2
• Time in Patent Office: Days
• US Class Current: 600/481
• 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 system comprising:

an implantable medical device, the implantable medical device comprising;

a posture sensing circuit;

a physiological signal sensing circuit to sense a physiological signal, the physiological signal sensing circuit including at least one of a heart rate sensing circuit, a heart rate variability sensing circuit, a heart sound sensing circuit, a respiration rate sensing circuit, and a blood pressure sensing circuit;

a controller circuit, operatively coupled to the physiological signal sensing circuit and the posture sensing circuit, the controller circuit configured to detect a change in the physiological signal that occurs in association with a change in posture, the controller circuit further configured to generate a response as a function of the change in the physiological signal, wherein the change in the physiological signal includes 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 different from a normal subject'"'"'s change in blood pressure;

a sensed change in heart sound energy that is different from a normal subject'"'"'s change in heart sound energy;

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

a sensed change in respiration rate when the change in posture includes one or more changes among a supine posture, a prone posture, a right lateral decubitus posture, and a left lateral decubitus posture.

2. The system of claim 1, further comprising a telemetry circuit operatively coupled to the controller circuit, wherein the response generated by the controller circuit comprises an alert issued by the telemetry circuit to an external device.

3. The system of claim 1, comprising a pacing circuit coupled to the controller circuit, wherein the response generated by the controller circuit is to adjust pacing delivered by the pacing circuit.

4. The system of claim 3, wherein the response generated by the controller circuit is to adjust a pacing location of the pacing delivered by the pacing circuit.

5. The system of claim 3, wherein the response generated by the controller circuit is to adjust a cardiac resynchronization therapy timing between paces delivered by the pacing circuit.

6. The system of claim 1, further comprising a neural stimulation circuit operatively coupled to the controller circuit, wherein the response generated by the controller circuit is to adjust a neural stimulation pulse.

7. The system of claim 1, further comprising a drug delivery control circuit operatively coupled to the controller circuit, wherein the response generated by the controller circuit is to adjust delivery of a substance.

8. The system of claim 1, in which the physiological sensing circuit is a heart rate sensing circuit.

9. The system of claim 8, in which the heart rate sensing circuit senses a change in heart rate that is different from a normal subject'"'"'s change in heart rate.

10. The system of claim 1, in which the physiological sensing circuit is a heart sound sensing circuit.

11. The system of claim 10, in which the heart sound sensing circuit senses a change in heart sound energy that is different from a normal subject'"'"'s change in heart sound energy.

12. The system of claim 1, in which the physiological sensing circuit is a respiration sensing circuit.

13. The system of claim 12, in which the respiration sensing circuit senses a change in respiration rate when the change in posture includes one or more changes among a supine posture, a prone posture, a right lateral decubitus posture, and a left lateral decubitus posture.

14. The system of claim 1, in which the physiological sensing circuit is a blood pressure sensing circuit.

15. The system of claim 14, in which the blood pressure sensing circuit senses a change in blood pressure that is different from a normal subject'"'"'s change in blood pressure.

16. The system of claim 1, in which the physiological sensing circuit is a heart rate variability sensing circuit.

17. The system of claim 16, in which the heart rate variability sensing circuit senses a change in heart rate variability that is different from a normal subject'"'"'s change in heart rate variability.

18. The system of claim 1, further comprising a circuit to compare the change in the physiological signal, the comparison comprising (1) a ratio of the physiological signal in a first posture to the physiological signal in a second posture for a subject with a possible health condition, to (2) a ratio of the physiological signal in a first posture to the physiological signal in a second posture for a normal subject or population.

19. The system of claim 18, 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.

20. 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 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.

21. The method of claim 20, further comprising a circuit to compare the change in the physiological signal, the comparison comprising (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.

22. The method of claim 21, 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.

23. The method of claim 20, further comprising identifying one or more of a progression and regression of a health condition as a function of the change in the physiological parameter.

24. A system comprising:

an implantable medical device, the implantable medical device comprising;

a posture sensing circuit;

a physiological signal sensing circuit to sense a physiological signal, the physiological signal sensing circuit including at least one of a heart rate sensing circuit, a heart rate variability sensing circuit, a heart sound sensing circuit, a respiration rate sensing circuit, and a blood pressure sensing circuit;

a controller circuit, operatively coupled to the physiological signal sensing circuit and the posture sensing circuit, the controller circuit configured to detect a change in the physiological signal that occurs in association with a change in posture, the controller circuit further configured to identify a health condition as a function of the change in the physiological signal, wherein the heart failure condition is identified by 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 different from a normal subject'"'"'s change in blood pressure;

a sensed change in heart sound energy that is different from a normal subject'"'"'s change in heart sound energy;

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

a sensed change in respiration rate when the change in posture includes one or more changes among a supine posture, a prone posture, a right lateral decubitus posture, and a left lateral decubitus posture.

25. The system of claim 24, further comprising a circuit to generate a response when the comparison indicates a change in the health condition;

and wherein the circuit to generate a response comprises one or more of a pacing circuit, a neural stimulation circuit, and a pharmaceutical delivery circuit.