Medical therapy apparatus which administers therapy adjusted to follow natural variability of the physiological function being controlled

• US 5,690,688 A
• Filed: 11/12/1996
• Issued: 11/25/1997
• Est. Priority Date: 11/12/1996
• Status: Expired due to Term

• Current Assignee: Pacesetter AB
• Original Assignee: Pacesetter AB
• Inventors: Noren, Kjell, Hirschberg, Jakub
• Primary Examiner(s): GETZOW, SCOTT M
• Application Number:
  US08/745,735
• Time in Patent Office: 378 Days
• Field of Search: 607/5, 607/6, 607/7, 607/9, 607/17
• US Class Current: 607/17
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585

Abstract

In a medical therapy apparatus, such as a pacemaker, a physiological function which is to be artificially controlled by therapy administration has a natural variability associated therewith. The medical therapy apparatus generates a basic therapy which would otherwise be supplied to the subject in the absence of such natural variability. The medical therapy apparatus further includes a non-linear oscillator which emits a chaotic output, the chaotic output of the non-linear oscillator being matched to the variability of the physiological function in order to produce a variability adjustment. The basic therapy is combined with the variability adjustment and a variability-adjusted therapy is then administered to the subject.

Claims

1. A medical therapy apparatus comprising:

means for generating a basic therapy for artificially controlling a physiological function of a subject, said physiological function having a natural variability associated therewith;

a non-linear oscillator having an output;

means for matching said output of said non-linear oscillator to said natural variability of said physiological function to produce a variability adjustment;

means for combining said basic therapy and said variability adjustment to generate a variability-adjusted therapy; and

means for administering said variability-adjusted therapy to said subject.

2. A medical therapy apparatus as claimed in claim 1 further comprising:

means for obtaining a physiological measurement over time from said subject; and

said means for artificially controlling a physiological function of said subject comprising means for artificially controlling said physiological function of said subject dependent on said physiological measurement.

3. A medical therapy apparatus as claimed in claim 1 wherein said means for matching said output of said non-linear oscillator to said natural variability of said physiological function comprises means for multiplying said output of said non-linear oscillator by a scaling factor.

4. A medical therapy apparatus as claimed in claim 3 wherein said basic therapy has a basic therapy value associated therewith, and further comprising means for setting said scaling factor as a fraction of said basic therapy value.

5. A medical therapy apparatus as claimed in claim 1 wherein said non-linear oscillator comprises means for modeling a chaotic system.

6. A medical therapy apparatus as claimed in claim 1 wherein said non-linear oscillator comprises means for modeling a Lorentz system.

7. A medical therapy apparatus as claimed in claim 1 wherein said non-linear oscillator comprises means for modeling a Duffin system.

8. A medical therapy apparatus as claimed in claim 1 wherein said non-linear oscillator comprises means for modeling a Rossler system.

9. A medical therapy apparatus as claimed in claim 1 wherein said non-linear oscillator comprises means for modeling a Mackey-Glass system.

10. A medical therapy apparatus as claimed in claim 1 further comprising means for generating a random value from said basic therapy and wherein said means for combining comprises means for combining said basic therapy, said variability adjustment and said random value to generate said variability-adjusted therapy.

11. A medical therapy apparatus as claimed in claim 1 further comprising means for initializing said non-linear oscillator with initial data values.

13. A medical therapy apparatus as claimed in claim 1 wherein said non-linear oscillator comprises means for modeling a non-autonomous chaotic system and further comprising means for supplying said means for modeling a non-autonomous chaotic system with an external data feed.

12. A medical therapy apparatus as claimed in claim wherein said non-linear oscillator comprises means for modeling an autonomous chaotic system.

14. A pacemaker for artificially controlling a heartbeat rate of a subject, said heartbeat rate having a natural variability associated therewith, said pacemaker comprising:

pulse generator means for generating a plurality of successive pacing pulses respectively separated by pulse intervals;

control means for setting a basic pacing rate;

a non-linear oscillator having an output;

means for matching said output of said non-linear oscillator to said natural variability of said heartbeat rate to produce a variability adjustment;

means for combining said basic rate with said variability adjustment to generate a variability-adjusted stimulation rate, said pulse generator means emitting said stimulation pulses at said variability-adjusted stimulation rate; and

means for delivering said stimulation pulses at said variability-adjusted stimulation rate to a heart of said subject.

15. A pacemaker as claimed in claim 14 further comprising:

means for obtaining a physiological measurement over time from said subject; and

said control means for artificially controlling a physiological function of said subject comprising means setting said basic pacing rate dependent on said physiological measurement.

16. A pacemaker as claimed in claim 14 wherein said means for matching said output of said non-linear oscillator to said natural variability of said physiological function comprises means for multiplying said output of said non-linear oscillator by a scaling factor.

17. A pacemaker as claimed in claim 16 further comprising means for setting said scaling factor as a fraction of said basic pacing rate.

18. A pacemaker as claimed in claim 14 wherein said non-linear oscillator comprises means for modeling a chaotic system.

19. A pacemaker as claimed in claim 14 wherein said non-linear oscillator comprises means for modeling a Lorentz system.

20. A pacemaker as claimed in claim 14 wherein said non-linear oscillator comprises means for modeling a Duffin system.

21. A pacemaker as claimed in claim 14 wherein said non-linear oscillator comprises means for modeling a Rossler system.

22. A pacemaker as claimed in claim 14 wherein said non-linear oscillator comprises means for modeling a Mackey-Glass system.

23. A pacemaker as claimed in claim 14 further comprising means for generating a random value from said basic therapy and wherein said means for combining comprises means for combining said basic therapy, said variability adjustment and said random value to generate said variability-adjusted therapy.

24. A pacemaker as claimed in claim 14 further comprising means for initializing said non-linear oscillator with initial data values.

25. A pacemaker as claimed in claim 14 wherein said non-linear oscillator comprises means for modeling an autonomous chaotic system.

26. A pacemaker as claimed in claim 14 wherein said non-linear oscillator comprises means for modeling a non-linear chaotic system and further comprising means for supplying said means for modeling a non-autonomous chaotic system with an external data feed.

27. A pacemaker as claimed in claim 14 further comprising value buffer means connected between said output of said non-linear oscillator and said means for matching for controlling transfer of signals from said output of said non-linear oscillator to said means for matching.

28. A pacemaker as claimed in claim 27 wherein said value buffer means comprises an N-position memory, controlled by said control means, for reading in and writing out values of said output of said non-linear oscillator, and said control means comprising means for controlling said N-position memory for reading data into said N-position memory at a rate different from reading out said data from said N-position memory.

29. A pacemaker as claimed in claim 14 wherein said non-linear oscillator comprises:

a non-linear oscillator stage which models a chaotic system and which emits a chaotic output; and

post-processing means, supplied with said chaotic output for generating an output having a time average of zero.

30. A medical therapy apparatus comprising:

means for administering medical therapy to a subject;

means for modeling a plurality of possible therapy procedures, each therapy procedure having a set of variables associated therewith, for obtaining a plurality of modeled therapy procedure results;

random variable generator means, including a non-linear oscillator, for generating a plurality of random variables for use as said sets of variables; and

means for selecting one of said modeled therapy procedure results as optimum for a subject to whom said therapy is to be administered.