Transient sensor response to posture as a measure of patient status

• US 9,066,659 B2
• Filed: 04/02/2012
• Issued: 06/30/2015
• Est. Priority Date: 04/08/2011
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Thakur, Pramodsingh Hirasingh, Patangay, Abhilash, Hatlestad, John D., Beck, Kenneth C.
• Primary Examiner(s): Lin, Jerry
• Application Number:
  US13/437,318
• Publication Number:
  US 20120259183A1
• Time in Patent Office: 1,184 Days
• Field of Search: 703/11
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0462 Apparatus with built-in sensors
• 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 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• 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 5/1118 Determining activity level
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/4848 Monitoring or testing the effects of treatment, e.g. of medication
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61N 1/36535 controlled by body position or posture
• 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

Abstract

Patient posture information can be received, such as to indicate a change in patient posture by at least a threshold amount. A transient response signal indicative of a change in a physiological parameter can be received at multiple instances near a change in patient posture. Waveform morphology features can be extracted from a transient response signal and used to provide an indication of a cardiac status, such as a heart failure status.

Claims

1. An apparatus, comprising:

a processor circuit, including;

a first data input configured to receive information indicative of a change in posture status;

a second data input configured to receive, at multiple instances temporally near or at the change in posture status, a transient response signal of a physiological parameter in response to the change in posture status, the transient response signal representing temporal variation of the physiological parameter occurring during the change in posture status; and

a processor-readable medium, including instructions that, when performed by the processor circuit, configure the apparatus to;

extract a waveform morphology feature from the transient response signal, the waveform morphology feature occurring during the change in posture status;

provide an indication of a cardiac status using the extracted waveform morphology feature; and

display the indication in an output device; and

a therapy delivery circuit configured to deliver a therapy based at least on the indication of the cardiac status.

2. The apparatus of claim 1, wherein the processor circuit includes a first data input configured to receive information indicative of a change in posture status from a first posture to a different second posture.

3. The apparatus of claim 1, wherein the processor circuit includes a second data input configured to receive, at multiple instances temporally near or at the change in posture status, a transient response signal of a physiological parameter in response to the change in posture status, wherein the physiological parameter includes at least one of:

a heart rate;

a blood pressure;

a heart sound metric;

a heart rate variability;

a blood oxygen concentration;

a blood carbon dioxide concentration;

a respiration rate;

a thoracic impedance;

or

a lung tidal volume.

4. The apparatus of claim 1, wherein the processor-readable medium includes instructions that, when performed by the processor circuit, configure the apparatus to extract a waveform morphology feature from the transient response signal, wherein the extracted waveform morphology feature indicates at least one of:

a magnitude of change of a portion of the transient response signal;

or

a duration of a portion of the transient response signal.

5. The apparatus of claim 1, wherein the processor-readable medium includes instructions that, when performed by the processor circuit, configure the apparatus to provide an indication of a cardiac status using the extracted waveform morphology feature, wherein the indication of a cardiac status indicates at least one of:

a heart failure status;

a chronotropic incompetence status;

an effectiveness of autonomic modulation therapy;

or

an effectiveness of a cardiovascular therapy.

6. The apparatus of claim 1, wherein the processor-readable medium includes instructions that, when performed by the processor circuit, configure the apparatus to provide an indication of a cardiac status using a trend of the extracted waveform morphology feature over multiple like-changes in posture status.

7. The apparatus of claim 6, wherein the processor-readable medium includes instructions that, when performed by the processor circuit, configure the apparatus to provide an indication of a cardiac status using a multiple-day trend of the extracted waveform morphology feature, the waveform morphology feature determined using a central tendency computed over multiple like-changes in posture status.

8. The apparatus of claim 7, wherein the processor-readable medium includes instructions that, when performed by the processor circuit, configure the apparatus to provide an indication of a cardiac status using a multiple-day trend of the extracted waveform morphology feature, the waveform morphology feature determined using a central tendency over multiple like-changes in patient posture status from a substantially recumbent posture to a substantially upright posture.

9. The apparatus of claim 1, wherein the processor-readable medium includes instructions that, when performed by the processor circuit, configure the apparatus to extract a waveform morphology feature from the transient response signal, the waveform morphology feature including at least one of a delay duration, a decay duration, a natural frequency of oscillation, or a magnitude change of a portion of the transient response signal;

and

provide the indication of a cardiac status using at least one of the delay duration, the decay duration, the natural frequency of oscillation, or the magnitude change of a portion of the transient response signal.

10. The apparatus of claim 9, wherein the processor-readable medium includes instructions that, when performed by the processor circuit, configure the apparatus to compare the waveform morphology feature to a metric;

and

provide the indication of a cardiac status, including an indication of a heart failure status, using the comparison.

11. A method for operating an apparatus, the method comprising, by the apparatus:

receiving information indicative of a change in posture status;

receiving, at multiple instances temporally near or at the change in posture status, a transient response signal of a physiological parameter in response to the change in posture status the transient response signal representing temporal variation of the physiological parameter occurring during the change in posture status;

extracting a waveform morphology feature from the transient response signal, the waveform morphology feature occurring during the change in posture status;

providing an indication of a cardiac status using the extracted waveform morphology feature;

displaying the indication in an output device; and

delivering a therapy based at least on the indication of the cardiac status.

12. The method of claim 11, wherein the receiving, at multiple instances temporally near or at the change in posture status, a transient response signal of a physiological parameter in response to the change in posture status includes receiving a transient response signal indicative of at least one of a posture change between:

a substantially recumbent posture and a substantially upright posture;

or

a first substantially recumbent posture and a different, second substantially recumbent posture.

13. The method of claim 11, wherein the receiving, at multiple instances temporally near or at the change in posture status, a transient response signal of a physiological parameter in response to the change in posture status includes receiving a transient response signal of a physiological parameter, the physiological parameter including at least one of:

a heart rate;

a blood pressure;

a heart sound metric;

a heart rate variability;

a blood oxygen concentration;

a blood carbon dioxide concentration;

a respiration rate;

a thoracic impedance;

or

a lung tidal volume.

14. The method of claim 11, wherein the extracting a waveform morphology feature from the transient response signal includes extracting, from the transient response signal, at least one of:

a magnitude of change of the transient response signal;

or

a duration of a portion of the transient response signal.

15. The method of claim 11, wherein the providing an indication of a cardiac status using the extracted waveform morphology feature includes providing an indication of at least one of:

a heart failure status;

a chronotropic incompetence status;

an effectiveness of autonomic modulation therapy;

or

an effectiveness of a cardiovascular therapy.

16. The method of claim 11, wherein the providing an indication of a cardiac status using the extracted waveform morphology feature includes providing an indication of a cardiac status using a trend of the extracted waveform morphology feature over multiple like-changes in posture status.

17. The method of claim 16, wherein the providing an indication of a cardiac status using a trend includes providing an indication of a cardiac status using a multiple-day trend of the extracted waveform morphology feature, the waveform morphology feature determined using a central tendency computed over multiple like-changes in posture status.

18. The method of claim 11, including determining a characteristic parameter of the transient response signal, the characteristic parameter including at least one of a delay duration, a decay duration, a natural frequency of oscillation, or a magnitude change of a portion of the transient response signal;

and

providing the indication of a cardiac status using the characteristic parameter.

19. The method of claim 18, wherein the providing the indication of a cardiac status using the characteristic parameter includes comparing the characteristic parameter to a metric;

and

providing the indication of a cardiac status, including an indication of a heart failure status, using the comparison.

20. An apparatus, comprising:

a processor circuit, including;

a first data input configured to receive information indicative of a change in posture status;

a second data input configured to receive, at multiple instances temporally near or at the change in posture status, a transient response signal of a physiological parameter in response to the change in posture status, the transient response signal representing temporal variation of the physiological parameter occurring during the change in posture status; and

a processor-readable medium, including instructions that, when performed by the processor circuit, configure the apparatus to;

model the transient response signal representing the temporal variation of the physiological parameter during the change in posture status as a first or second order system response signal occurring during the change in posture status;

extract a characteristic parameter of the modeled first or second order system signal, the characteristic parameter including at least one of a delay duration, a decay duration, a natural frequency of oscillation, or a magnitude change, of a portion of the system response signal that includes the temporal variation of the physiological parameter during the change in posture status;

provide, using the extracted characteristics parameter, an indication of worsening heart failure; and

display the indication in an output device; and

a therapy delivery circuit configured to deliver a therapy based at least on the indication of the cardiac status.