Rate smoothing control

• US 20030078630A1
• Filed: 11/27/2002
• Published: 04/24/2003
• Est. Priority Date: 05/26/2000
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Lovett, Eric G., Palreddy, Surekha
• Granted Patent: US 7,069,077 B2
• Time in Patent Office: Days
• US Class Current: 607/27
• 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

A rate smoothing function used in implantable pulse generators, where detected triggering events cause the rate smoothing function to be activated or deactivated and detected parameter adjusting events cause parameters of the rate smoothing function to be changed. The activation/deactivation and/or change to the parameters of the rate smoothing function are temporary, and the pre-event state of the rate smoothing function is set to a post-adjusting state. In one embodiment, the pre-event state of the rate smoothing function is set to the post-adjusting state after a first time interval.

Claims

1. A method, comprising:

monitoring for a triggering event; and

when the triggering event is detected, activating a rate smoothing system.

2. The method of claim 1, including deactivating the rate smoothing system after a first time interval.

3. The method of claim 1, wherein the triggering event is a short-long-short cycle length sequence.

4. The method of claim 1, wherein the monitoring comprises:

monitoring an activity signal; and

detecting the triggering event when the activity signal exceeds a first predetermined value.

5. The method of claim 4, where the activity signal is a heart rate trajectory.

6. The method of claim 4, where monitoring the activity signal includes monitoring an accelerometer signal.

7. The method of claim 4, where monitoring the activity signal includes monitoring a minute ventilation signal.

8. The method of claim 1, where monitoring for the triggering event includes:

monitoring a cardiac signal which includes indications of ventricular contractions;

analyzing the cardiac signal for the occurrence of a premature ventricular contraction (PVC); and

detecting the triggering event when one or more of the PVC occur.

9. The method of claim 1, where monitoring for the triggering event includes:

monitoring a time interval; and

detecting the triggering event at a first time in the time interval.

10. The method of claim 1, where monitoring for the triggering event includes:

detecting an arrhythmic episode;

identifying an end to the arrhythmic episode; and

declaring the triggering event after the end of the arrhythmic episode.

11. The method of claim 10, where detecting the arrhythmic episode includes detecting either a ventricular tachycardia or a ventricular bradycardia.

12. The method of claim 1, including detecting the triggering event when a pacemaker mode is changed.

13. The method of claim 1, including detecting the triggering event when a cardiac rate exceeds a rate threshold.

14. The method of claim 1, where monitoring for the triggering event includes receiving a request for triggering event;

analyzing a cardiac condition; and

issuing the triggering event based on the analysis of the cardiac condition.

15. The method of claim 1, where monitoring the triggering event includes:

sensing a cardiac signal;

analyzing the cardiac signal with a stability algorithm; and

identifying the triggering event from the sensed cardiac signal with the stability algorithm.

16. A method, comprising:

monitoring for a parameter adjusting event; and

when the parameter adjusting event is detected, adjusting parameters of a rate smoothing system.

17. The method of claim 16, including setting the parameters of the rate smoothing system to a post adjusting state after a first time interval.

18. The method of claim 16, wherein the parameter adjusting event is a short-long-short cycle length sequence.

19. The method of claim 16, wherein the monitoring comprises:

monitoring an activity signal; and

detecting the parameter adjusting event when the activity signal exceeds a first predetermined value.

20. The method of claim 19, where the activity signal is a heart rate trajectory.

21. The method of claim 19, where monitoring the activity signal includes monitoring an accelerometer signal.

22. The method of claim 19, where monitoring the activity signal includes monitoring a minute ventilation signal.

23. The method of claim 16, where monitoring for the parameter adjusting event includes:

monitoring a cardiac signal which includes indications of ventricular contractions;

analyzing the cardiac signal for the occurrence of a premature ventricular contraction (PVC); and

detecting the parameter adjusting event when one or more of the PVC occur.

24. The method of claim 16, where monitoring for the parameter adjusting event includes:

monitoring a time interval; and

detecting the parameter adjusting event at a first time in the time interval.

25. The method of claim 16, where monitoring for the parameter adjusting event includes:

detecting an arrhythmic episode;

identifying an end to the arrhythmic episode; and

declaring the parameter adjusting event after the end of the arrhythmic episode.

26. The method of claim 25, where detecting the arrhythmic episode includes detecting either a ventricular tachycardia or a ventricular bradycardia.

27. The method of claim 16, including detecting the parameter adjusting event when a pacemaker mode is changed.

28. The method of claim 16, including detecting the parameter adjusting event when a cardiac rate exceeds a rate threshold.

29. The method of claim 16, where monitoring for the parameter adjusting event includes receiving a request for parameter adjusting event;

analyzing a cardiac condition; and

issuing the parameter adjusting event based on the analysis of the cardiac condition.

30. The method of claim 16, where monitoring the parameter adjusting event includes:

sensing a cardiac signal;

analyzing the cardiac signal with a stability algorithm; and

identifying the parameter adjusting event from the sensed cardiac signal with the stability algorithm.

31. A system, comprising:

a signal input system, where the signal input system is adapted to monitor a signal;

control circuitry coupled to the signal input system, where the control circuitry receives the signal from the signal input system and where the control circuity includes;

a trigger event detector, where the trigger event detector is adapted to detect a trigger event in the signal; and

a rate smoothing module, where the rate smoothing module is activated to provide rate smoothing when the trigger event is detected.

32. The system of claim 31, where the signal input system is a cardiac signal sensing system adapted to detected a ventricular cardiac signal, and where the trigger event detector detects the trigger event when a series of consecutive ventricular intervals having a short-long-short sequence is detected.

33. The system of claim 31, where the signal input system includes a minute ventilation sensor and where the trigger event detector detects the trigger event in the signal from the minute ventilation sensor when the signal exceeds a first value.

34. The system of claim 31, where the signal input system includes an accelerometer sensor and where the trigger event detector is adapted to detect the trigger event in the signal from the accelerometer sensor when the signal exceeds a first value.

35. The system of claim 31, where the signal input system is a cardiac electrode system adapted to detected a ventricular cardiac signal, and where the trigger event detector is adapted to detect premature ventricular contractions in the ventricular cardiac signal as the trigger event.

36. The system of claim 31, where the signal input system is adapted to receive a ventricular cardiac signal, and where the control circuitry further incudes an arrhythmia detection circuit, where the arrhythmia detection circuit is coupled to the signal input system and receives and analyzes the ventricular cardiac signal to detect an arrhythmic episode, including an end to the arrhythmic episode, and where the trigger event detector declares the triggering event at the end of the arrhythmic episode.

37. A system, comprising:

a signal input system, where the signal input system is adapted to detect a signal;

control circuitry coupled to the signal input system, where the control circuitry receives the signal from the signal input system and where the control circuity includes;

a parameter adjustment event detector, where the parameter adjustment event detector is adapted to detect a parameter adjustment event in the signal; and

a rate smoothing module, where the rate smoothing module adjusts rate smoothing parameters when the parameter adjustment event is detected.

38. The system of claim 37, where the signal input system is a cardiac signal sensing system adapted to detected a ventricular cardiac signal, and where the parameter adjustment event detector detects the parameter adjustment event when a series of consecutive ventricular intervals having a short-long-short sequence is detected.

39. The system of claim 37, where the signal input system includes a minute ventilation sensor and where the parameter adjustment event detector detects the parameter adjustment event in the signal from the minute ventilation sensor when the signal exceeds a first value.

40. The system of claim 37, where the signal input system includes an accelerometer sensor and where the parameter adjustment event detector is adapted to detect the parameter adjustment event in the signal from the accelerometer sensor when the signal exceeds a first value.

41. The system of claim 37, where the signal input system is a cardiac electrode system adapted to detected a ventricular cardiac signal, and where the parameter adjustment event detector is adapted to detect premature ventricular contractions in the ventricular cardiac signal as the parameter adjustment event.

42. The system of claim 37, where the signal input system is adapted to receive a ventricular cardiac signal, and where the control circuitry further incudes an arrhythmia detection circuit, where the arrhythmia detection circuit is coupled to the signal input system and receives and analyzes the ventricular cardiac signal to detect an arrhythmic episode, including an end to the arrhythmic episode, and where the parameter adjustment event detector declares the parameter adjustment event at the end of the arrhythmic episode.