Process for detection of physical position of a human being

• US 6,308,098 B1
• Filed: 09/08/1999
• Issued: 10/23/2001
• Est. Priority Date: 09/08/1998
• Status: Expired due to Fees

• Current Assignee: Biotronik Mess-Und Therapiegeraete GmbH & Company Ingenieurbuero Berlin (Biotronik SE & Company KG)
• Original Assignee: Biotronik Mess-Und Therapiegeraete GmbH & Company Ingenieurbuero Berlin (Biotronik SE & Company KG)
• Inventors: Meyer, Wolfgang
• Primary Examiner(s): EVANISKO, GEORGE ROBERT
• Application Number:
  US09/391,857
• Time in Patent Office: 776 Days
• Field of Search: 607/9, 607/17, 607/19, 607/20, 607/23, 607/24, 607/26, 600/547, 600/595
• 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 1/36535 controlled by body position or posture

Abstract

A process for detecting the physical positions or changes of position of a human being based on detecting a physiological signal dependent on a sympathetic/parasympathetic nerve system in each case in the heart or in a vessel near the heart by means of a sensor at pre-specified times, in particular, based in each case on a physiological or stimulation event, deriving a value of a signal parameter in each case, from this signal according to a pre-specified signal processing rule and stored determining a fluctuation curve of the stored signal parameter values, performing a frequency analysis of the fluctuation curve to obtain the spectral power density evaluating the spectral power density, resulting in the issuance of a position signal as a function of the evaluation result, whereby the morphology of the signals is detected and the value of the signal parameter is, in each case, derived from morphology of an individual detected signal.

Claims

1. A process for detecting physical positions or changes of position of a human being, comprising:

detecting a plurality of physiological signals dependent on a sympathetic/parasympathetic nerve system in a heart of a human being or in a vessel near the heart of the human being by a sensor at pre-specified times, each of said pre-specified times corresponding to a physiological or a stimulation event;

deriving and storing a plurality of values as signal parameters from the plurality of physiological signals according to a pre-specified signal processing rule;

determining a fluctuation curve of the stored signal parameter values;

performing a frequency analysis of the fluctuation curve to obtain a spectral power density;

evaluating the spectral power density based on a predefined algorithm;

issuing a position signal as a function of the evaluation of the spectral power density;

wherein detecting includes detection of a morphology for each of the plurality of physiological signals and wherein deriving includes derivation of the values as signal parameters in each case from the morphology of an individually detected signal.

2. A process according to claim 1, wherein evaluating the spectral power density includes determining a relationship of the values of the spectral power density in at least two pre-specified frequency ranges and wherein issuing includes issuing the position signal as a function of the relationship determined.

3. A process according to claim 1, wherein the physiological signal is an intracardially, unipolarly detected impedance signal or a ventricular evoked response and a contractility parameter.

4. A process according to claims 1 or 2, wherein signal detection is undertaken in sync with natural or evoked heart beats and a determination of fluctuation values is undertaken on a beat by beat basis.

5. A process according to claim 1, wherein spectral power densities are integrated into pre-specified frequency ranges and a relationship is developed from integral values.

6. A process according to claim 1, wherein a relationship of spectral power densities is developed in a first range of frequencies from 0.05 to 0.15 Hz to in a second range of frequencies from 0.15 to 0.4 Hz.

7. A process according to claim 1, wherein beat by beat variability of a plurality of intracardial impedance signals is used for detecting position changes of a human being.

16. A process according to claim 1, wherein the signal parameters comprise impedance or VER signals.

8. An apparatus for detecting physical positions or changes of position of a human being, comprising:

a sensor locatable in a heart of the human being or a vessel near the heart for detecting a plurality of morphologically faithful, physiological signals;

a control unit to actuate the sensor at pre-specified times, which is adapted to be connected to a physiological event detector or a stimulation signal generator;

a plurality of first processing units connected to an input side of the sensor for determining a plurality of values as signal parameters from the morphology of the signals detected according to a pre-specified signal processing rule;

signal parameter memory for storing the signal parameter values determined previously;

a second processing unit connected to an input side of the signal parameter memory for determining a fluctuation curve of the stored signal parameter values;

a frequency analyzer connected to an input side of the second processing unit for obtaining a spectral power density from the fluctuation curve;

a third processing unit connected to an input side of the frequency analyzer for determining a relationship of the values of the spectral power density in at least two pre-specified frequency ranges; and

a comparator and an evaluation unit connected to an input side of the third processing unit to issue a position signal as a function of the relationship determined.

9. An apparatus according to claim 8, wherein the sensor comprises a unipolar, intracardial electrode arrangement, a filter and an amplification stage designed to detect the morphology of an intracardial EKG or impedance signal.

10. An apparatus according to claims 8 or 9, wherein the frequency analyzer is designed to perform an autoregressive spectral analysis for obtaining the spectral power density.

11. An apparatus according to claim 8, the third processing unit comprises an integrator stage and an arithmetic calculation unit connected downstream therefrom.

12. An apparatus according to claim 8, wherein the physiological signals comprise a plurality of intracardial impedance signals having beat-by-beat variability.

13. An apparatus according to claim 8, wherein the sensor comprises a plurality of electrodes.

14. Implantable cardiotherapy device for detecting physical positions or changes of position of a human being, comprising:

a sensor locatable in a heart of the human being or a vessel near the heart for detecting a plurality of morphologically faithful, physiological signals;

a control unit to actuate the sensor at pre-specified times, which is adapted to be connected to a physiological event detector or a stimulation signal generator;

a plurality of first processing units connected to an input side of the sensor for determining a plurality of values as signal parameters from the morphology of the signals detected according to a pre-specified signal processing rule;

signal parameter memory for storing the signal parameter values determined previously;

a second processing unit connected to an input side of the signal parameter memory for determining a fluctuation curve of the stored signal parameter values;

a frequency analyzer connected to an input side of the second processing unit for obtaining a spectral power density from the fluctuation curve;

a third processing unit connected to an input side of the frequency analyzer for determining a relationship of the values of the spectral power density in at least two pre-specified frequency ranges; and

a comparator and an evaluation unit connected to an input side of the third processing unit to issue a position signal as a function of the relationship determined.

15. An implantable cardiotherapy device according to claim 14, designed as a rate-adaptive cardiac pacemaker, the pacemaker having a rate specification stage for calculation of a stimulation rate, the stage having one input for reception of the position signal connected with the output of the comparator and an evaluation unit and being designed for the processing of the position signal for calculation of a stimulation rate.

17. An implantable cardiotherapy device according to claim 14, wherein the sensor comprises a unipolar, intracardial electrode arrangement, a filter and an amplification stage designed to detect the morphology of a intracardial EKG or impedance signal.

18. An implantable cardiotherapy device according to claim 14, wherein the frequency analyzer is designed to perform an autoregressive spectral analysis for obtaining the spectral power density.

19. An implantable cardiotherapy device according claim 14, wherein the third processing unit comprises an integrator stage and an arithmetic calculation unit connected downstream therefrom.

20. An implantable cardiotherapy device according to claim 14, wherein the physiological signals comprise a plurality of intracardial impedance signals having beat-by-beat variability.