Detecting heart failure by monitoring the time sequence of physiological changes

Patent metadata

Field	Value
Publication number	US-9420959-B2
Application number	US-201113324142-A
Country	US
Kind code	B2
Filing date	Dec 13, 2011
Priority date	Dec 15, 2010
Publication date	Aug 23, 2016
Grant date	Aug 23, 2016

Abstract

Systems and methods for detecting heart failure by monitoring the time-sequence of physiological changes of a subject using a state machine circuit configured to receive information about physiological characteristics of the subject is described. The current state transitions between a first and a second state in response to a first transition trigger. The current state transitions between the second and first states in response to at least one of the expiration of a first timer or ceasing of the first transition trigger. The current state transitions between the second and third states in response to a second transition trigger. The current state transitions between the third and second states in response to at least one of expiration of a second timer or ceasing of the second transition trigger.

First claim

The claimed invention is:

1. A system for monitoring a worsening heart failure condition, comprising:
a state machine circuit, configured to receive information about different first and second physiological characteristics of a subject, wherein the state machine comprises:
a state sequence of at least first, second, and third states, wherein a state represents a physiological status of the subject, at least one of the first, second, and third states correspond to a thoracic fluid status of the subject or a respiration status of the subject, and at least one of the first, second, and third states correspond to a non-fluid related status or non-respiration related status of the subject;
a first forward state transition from the first state to the second state in response to a first transition trigger;
a first reverse state transition from the second state to the first state in response to first of expiration of a first timer and ceasing of the first transition trigger prior to expiration of the first timer;
a second forward state transition from the second to the third state in response to a second transition trigger; and
a second reverse state transition from the third state to the second state in response to first of expiration of a second timer and ceasing of the second transition trigger prior to expiration of the first timer.

2. The system of claim 1 , wherein the first reverse state transition is in response to the expiration of a third timer, wherein the third timer corresponds with a maximum time to complete the state sequence.

3. The system of claim 2 , further comprising a third reverse state transition, wherein the third reverse state transition is in response to the expiration of the third timer.

4. The system of claim 3 , wherein the state machine circuit further comprises:
the state sequence, wherein the state sequence further comprises a fourth state;
a third forward state transition between the first and fourth states in response to a third transition trigger;
a fourth reverse state transition between the fourth and first states in response to at least one of expiration of a fourth timer or ceasing of the third transition trigger, wherein the fourth timer is capable of being set to a different time limit value than the first, second and third timer values;
a fourth forward state transition between the fourth and second states in response to a fourth transition trigger; and
a fifth reverse state transition between the second and fourth states in response to at least one of expiration of a fifth timer or ceasing of the third transition trigger, wherein the fifth timer is capable of being set to a different time limit value than the first, second, third and fourth timer values.

5. The system of claim 1 , further comprising a plurality of physiological sensors, wherein the physiological sensors produce respective physiological signals including information about the first and second physiological characteristics.

6. The system of claim 5 , wherein the plurality of physiologic sensors includes at least one ambulatory sensor.

7. The system of claim 1 , wherein the first and second transition triggers further include a time sequence parameter, wherein the time sequence parameter corresponds to a minimum time prior to triggering the first and second forward state transition.

8. The system of claim 1 , wherein the first state comprises a baseline condition of a subject, wherein the baseline condition is associated with the first and second physiological characteristics.

9. The system of claim 1 , wherein the system further comprises a response circuit coupled to the state machine circuit, wherein the response circuit is operable to provide a specified response following the second forward state transition to the third state.

10. The system of claim 9 , wherein the specified response includes at least one of an alert and a report.

11. The system of claim 9 , wherein the third state corresponds to a clinical event of a subject.

12. The system of claim 11 , wherein the third state further corresponds to a worsening heart failure event of the subject.

13. The system of claim 1 , wherein the first and second timers are capable of being set with a variable time limit value, wherein the variable time limit value corresponds with at least one of the first and second physiological characteristics.

14. The system of claim 1 , wherein the second timer is capable of being set to a different time limit value from the first timer.

15. A method of monitoring a worsening heart failure condition using a medical device, comprising:
receiving information about different first and second physiological characteristics of a subject;
transitioning from a first state to a second state in a first forward state transition in response to a first transition trigger, wherein a state represents a physiological status of the subject, at least one of the first state, the second state, and a third state corresponds to a thoracic fluid status of the subject or a respiration status of the subject, and at least one of the first, second, and third states corresponds to a non-fluid related status or non-respiration related status of the subject;
transitioning from the second state to the first state in a first reverse transition in response to first of expiration of a first timer and ceasing of the first transition trigger prior to expiration of the first timer;
transitioning from the second state to the third state in a second forward state transition in response to a second transition trigger; and
transitioning from the third state to the second state in a second reverse transition in response to first of expiration of a second timer and ceasing of the second transition trigger prior to expiration of the first timer.

16. The method of claim 15 , further comprising receiving a plurality of physiological signals from respective physiological sensors, wherein the physiological signals include information about the first and second physiological characteristics.

17. The method of claim 15 , wherein the physiological sensors include at least one ambulatory sensor.

18. The method of claim 15 , wherein transitioning from the second state to the first state further includes a response to the expiration of a third timer, wherein the third timer corresponds with a maximum time to complete the state sequence.

19. The method of claim 15 , comprising transitioning from the third state to the first state in response to the expiration of the third timer.

20. The method of claim 15 , wherein the first and second transition triggers further include a time sequence parameter, wherein the time sequence parameter corresponds to a minimum time prior to transitioning from the first state to the second state or transitioning from the second state to the third state.

21. The method of claim 15 , wherein the first state comprises a baseline condition of a subject, wherein the baseline condition is associated with the first and second physiological characteristics.

22. The method of claim 15 , wherein the method further comprises communicating a specified response after transitioning from the second state to the third state.

23. The method of claim 22 , wherein the specified response includes an alert.

24. The method of claim 22 , wherein the specified response includes a report.

25. The method of claim 22 , wherein the third state corresponds to a clinical ev

Assignees

• Zhang Yi
• Averina Viktoria A
• Patangay Abhilash
• Wariar Ramesh
• Peterson Jon
• Cardiac Pacemakers Inc

Inventors

• Zhang Yi
• Averina Viktoria A
• Patangay Abhilash
• Wariar Ramesh
• Peterson Jon

Classifications

• A61B5/33

  specially adapted for cooperation with other devices · CPC title

• A61B5/29

  for permanent or long-term implantation · CPC title

• A61B5/4842

  Monitoring progression or stage of a disease · CPC title

• A61B5/042

  Human Necessities · mapped topic

• A61B7/00

  Instruments for auscultation · CPC title