Technique for discriminating between coordinated and uncoordinated cardiac rhythms

• US 7,369,890 B2
• Filed: 05/09/2003
• Issued: 05/06/2008
• Est. Priority Date: 11/02/2000
• Status: Expired due to Fees

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Lovett, Eric G.
• Primary Examiner(s): Layno; Carl
• Assistant Examiner(s): Oropeza; Frances P.
• Application Number:
  US10/435,487
• Publication Number:
  US 20040073262A1
• Time in Patent Office: 1,824 Days
• Field of Search: 600/509, 600/515, 600/516, 600/518, 600/519, 600/522, 600/373, 600/374, 600/393, 607/4, 607/5, 607/9, 607/14, 607/25, 607/28, 607/116, 607/119, 607/120, 607/122, 607/126, 607/128
• US Class Current: 600/515
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions

Abstract

A system and method for discriminating cardiac rhythms in sensed cardiac complexes associated with at least two cardiac signals, which includes at least two electrodes disposed at different locations in a heart for sensing at least two cardiac signals. A controller through a sensing circuit receives the sensed at least two cardiac signals from the electrodes and processes the sensed at least two cardiac signals to compute interelectrode time differences between the cardiac complexes associated with one of the at least two sensed cardiac signals, and corresponding cardiac complexes associated with the other of the at least two sensed cardiac signals. The controller further computes a detection time difference variability from the computed interelectrode detection time difference variabilities. Then the controller compares the computed detection time difference variability to a predetermined detection time difference variability threshold value to discriminate whether the sensed at least two cardiac signals have a coordinated or an uncoordinated cardiac rhythm.

Claims

1. A system adapted to be coupled to a heart having a first location and a second location, comprising:

at least two electrodes to sense a first cardiac signal from the first location and a second cardiac signal from the second location, the first and second signals associated with cardiac complexes;

a signal sensing circuit, coupled to the at least two electrodes to receive and amplify the cardiac complexes;

a controller, coupled to the signal sensing circuit, wherein the controller receives the amplified cardiac complexes, and wherein the controller comprises;

an analyzer to compute a set of interelectrode detection time differences each between one of the cardiac complexes associated with the first location and the one of the cardiac complexes associated with the second location for a predetermined time interval, wherein the interelectrode detection time differences are each a propagation time of one of the cardiac complexes from the first location to the second location;

wherein the analyzer further computes a detection time difference variability using the computed set of interelectrode detection time differences, wherein the detection time difference variability includes a measure of an average absolute value of the interelectrode detection time differences; and

a comparator, coupled to the analyzer, to compare the computed detection time difference variability with a predetermined detection time difference variability threshold value, classify the first and second signals based on the outcome of the comparison and issue a command signal based on the classification.

2. The system of claim 1, further comprises:

a therapy circuit coupled to the comparator, to deliver a high-energy electrical therapy through one of the at least two electrodes upon receiving the command signal from the comparator.

3. The system of claim 1, where the at least two electrodes are first and second electrodes.

4. The system of claim 3, wherein the first and second cardiac signals are associated with the first and second electrodes, respectively.

5. The system of claim 4, where the analyzer computes the set of interelectrode detection time differences between the sensing of the cardiac complexes associated with the first location and the sensing of the corresponding cardiac complexes associated with the second location, and

the analyzer further computes a second set of interelectrode detection time differences between the sensing of the cardiac complexes associated with the second location and the sensing of the corresponding cardiac complexes associated with the first location.

6. The system of claim 5, where the analyzer further computes a first detection time difference variability and a second detection time difference variability using the computed first and second set of interelectrode detection time differences, respectively.

7. The system of claim 6, where the comparator compares the computed first and second detection time difference variabilities with a predetermined detection time difference variability threshold value, and issues a command signal based on the outcome of the comparison.

8. The system of claim 7, where the comparator further classifies the sensed first and second cardiac signals based on the outcome of the comparison to identify a cardiac arrhythmia.

9. The system of claim 7, where the comparator further classifies the sensed first and second cardiac signals based on the outcome of the comparison to identify an atrial fibrillation from an atrial flutter.

10. The system of claim 7, where the comparator further classifies the sensed first and second cardiac signals based on the outcome of the comparison to identify a ventricular fibrillation from a ventricular tachycardia.

11. The system of claim 7, in which the controller further comprises:

a timer coupled to the comparator, to provide a predetermined variable delay in an electrical energy delivered through at least one of the at least two electrodes.

12. The system of claim 11, where the electrical energy is a pacing pulse electrical energy.

13. The system of claim 11, where the electrical energy is a defibrillation pulse electrical energy.

14. The system of claim 1, further comprising:

an implantable rhythm management device.

15. The system of claim 14, where the implanted rhythm management device further comprises:

a reservoir to hold a drug;

a pump coupled to the reservoir; and

a catheter, having a first end and a second end, where the first end is coupled to the pump, and the second end is adapted to deliver a drug therapy to one or more regions of a patient'"'"'s body, wherein the device administers the drug to the patient through the catheter upon receiving the command signal.

16. The system of claim 15, where the controller further comprises:

a timer, where the timer is coupled to the comparator and provides a predetermined time delay to administer the drug upon receiving the command signal from the comparator.

17. The system of claim 16, in which the predetermined time delay is approximately in the range of 1 second to 180 seconds.

18. The system of claim 1, wherein one of the first and second cardiac signals is an atrial signal.

19. The system of claim 1, wherein one of the first and second cardiac signals is a ventricular signal.

20. The system of claim 1, where the system comprises a cardiac rhythm management system.

21. The system of claim 1, where the predetermined time interval ‘

t’

includes ‘

N’

number of cardiac complexes sensed by one of the at least two electrodes.

22. The system of claim 21, where the ‘

N’

number of cardiac complexes are approximately in a range of about ten (10) to fifteen (15) cardiac complexes.

23. A controller to discriminate between coordinated and uncoordinated cardiac rhythms from sensed cardiac complexes associated with at least two cardiac signals sensed at two different locations of a heart having a first location and a second location, the controller comprising:

an analyzer, to compute a set of interelectrode detection time differences each between a sensed time when the one of the cardiac complexes associated with the first location occurs and a sensed time when the one of the cardiac complexes associated with the second location occurs for a predetermined time interval, wherein the interelectrode detection time differences are each a propagation time of the one of the cardiac complexes occurring from the first location to the second location, wherein the analyzer further computes a detection time difference variability in the computed set of interelectrode detection time differences, and wherein the detection time difference variability includes a measure of an average absolute value of the interelectrode detection time differences; and

a comparator, coupled to the analyzer, to compare the computed detection time difference variability with a predetermined detection time difference variability threshold value, classify the first and second signals based on the outcome of the comparison and issue a command signal based on the classification.

24. The controller of claim 23, where the comparator further classifies the sensed at least two cardiac signals to identify a cardiac arrhythmia based on the outcome of the comparison.

25. The controller of claim 24, where the comparator further classifies the sensed at least two cardiac signals based on the outcome of the comparison to identify an atrial fibrillation from an atrial flutter.

26. The controller of claim 24, where the comparator further classifies the sensed at least two cardiac signals based on the outcome of the comparison to identify a ventricular fibrillation from a ventricular tachycardia.

27. A method comprising:

computing interelectrode detection time differences from sensed cardiac complexes associated with at least two cardiac signals sensed at first and second locations in a heart, wherein the interelectrode detection time differences are each a propagation time of one of the sensed cardiac complexes from the first location to the second location;

computing a detection time difference variability from the computed interelectrode detection time differences, wherein the detection time difference variability includes a measure of an average absolute value of the interelectrode detection time differences; and

classifying the sensed at least two cardiac signals by comparing the computed detection time difference variability with a predetermined detection time difference variability threshold value.

28. The method of claim 27, wherein computing the interelectrode time differences further comprises:

computing a set of interelectrode detection time differences between the computed times when cardiac complexes associated with one of the at least two cardiac signals occur and the corresponding computed times when the cardiac complexes associated with the other of the at least two cardiac signals occur for a predetermined time interval.

29. The method of claim 28, further comprising:

discriminating a cardiac arrhythmia based on the outcome of the comparison.

30. The method of claim 29, where discriminating the cardiac arrhythmia further comprises:

discriminating an atrial fibrillation from an atrial flutter.

31. The method of claim 29, where discriminating the cardiac arrhythmia further comprises:

discriminating a ventricular fibrillation from a ventricular tachycardia.

32. The method of claim 29, wherein sensing the cardiac complexes associated with the at least two cardiac signals comprises:

sensing cardiac complexes associated with first and second cardiac signals.

33. The method of claim 32, wherein computing the times when the cardiac complexes associated with the sensed first and second cardiac signals comprises:

computing the times when the cardiac complexes associated with the first cardiac signal occur; and

computing the times when the corresponding cardiac complexes associated with the second cardiac signal occur.

34. The method of claim 33, where discriminating the cardiac arrhythmia further comprises:

computing a first set of interelectrode detection time differences between the sensed cardiac complexes associated with the first cardiac signal and the corresponding sensed cardiac complexes associated with the second cardiac signal, respectively;

computing a first detection time difference variability using the computed first set of interelectrode detection time differences;

computing a second set of interelectrode detection time differences between the sensed cardiac complexes associated with the second cardiac signal and the corresponding sensed cardiac complexes associated with the first cardiac signal, respectively;

computing a second detection time difference variability using the computed second set of interelectrode detection time differences;

comparing the computed first and second detection time difference variabilities to a predetermined detection time difference variability threshold value; and

issuing a command signal based on the outcome of the comparison.

35. The method of claim 34, further comprises:

discriminating the sensed first and second cardiac signals based on the outcome of the comparison.

36. The method of claim 34, where discriminating the first and second cardiac signals further comprises:

classifying the sensed first and second cardiac signals as coordinated cardiac rhythm or as an uncoordinated cardiac rhythm based on the outcome of the comparison.

37. The method of claim 34, further comprises:

providing a high-energy therapy to a heart through at least one of the at least two electrodes upon receiving the command signal.

38. The method of claim 34, further comprises:

providing a cardiac therapy to a heart upon receiving the command signal.

39. The method of claim 34, further comprises:

activating an implanted device to administer a drug therapy to the heart upon receiving the command signal.

40. The method of claim 34, where sensing the first and second cardiac signals comprises sensing atrial signals.

41. The method of claim 34, where sensing the first and second cardiac signals comprise sensing ventricular signals.

42. The method of claim 34, where the predetermined time interval ‘

t’

includes ‘

N’

number of cardiac complexes sensed by one of the at least two electrodes.

43. The method of claim 42, where the ‘

N’

number of cardiac complexes is approximately in a range of about ten (10) to fifteen (15).

44. The method of claim 34, further comprises:

computing a first and second average detection time difference using the corresponding computed first and second set of interelectrode detection time differences;

comparing the computed first and second detection time difference variabilities to the corresponding computed first and second average detection time difference variabilities;

determining a lower detection time difference variability based on the outcome of the comparison of the first and second detection time difference variabilities to reduce an effect of inflated detection time difference variability due to substantially longer cycle lengths introduced by a cardiac arrhythmia such as an atrial flutter;

comparing the determined lower detection time difference variability with a predetermined detection time difference variability threshold value; and

issuing a command signal based on the outcome of the comparison.