Apparatus and method for collecting data useful for determining the parameters of an alert window for timing delivery or ETC signals to a heart under varying cardiac conditions

• US 6,459,928 B2
• Filed: 01/24/2001
• Issued: 10/01/2002
• Est. Priority Date: 06/08/1999
• Status: Expired due to Term

• Current Assignee: Impulse Dynamics NV
• Original Assignee: Impulse Dynamics NV
• Inventors: Mika, Yuval, Belsky, Ziv, Prutchi, David, Routh, Andre G.
• Primary Examiner(s): JASTRZAB, JEFFREY R
• Application Number:
  US09/768,968
• Publication Number:
  US 20010031925A1
• Time in Patent Office: 615 Days
• Field of Search: 607/9, 607/11, 607/25, 607/68, 600/510
• US Class Current: 600/510
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: H01L 21/568 Temporary substrate used as encapsulation process aid H01L21/4832 and H01L21/566 take precedence
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 23/3107 the device being completely enclosed
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Apparatus and method for obtaining from a patient'"'"'s heart data useful for on-line setting of the parameters of a detection time window in an excitable tissue control device. The method includes applying electrodes to a first cardiac site and a second cardiac site of a patient and electrically connecting the electrodes to a data collecting device. The device is then operated under a plurality of different cardiac conditions to obtain a plurality of different histogram data sets. Each histogram data set represents a cumulative time distribution histogram of cardiac depolarization events detected at the second cardiac site in a plurality of cardiac beats. Each histogram data set is defined by a plurality of histogram parameters having values indicative of the cardiac conditions common to the plurality of cardiac beats used to obtain the histogram data set. The histogram parameters include a sensitivity level parameter representing the sensitivity level used for detecting the cardiac depolarization events of the plurality of cardiac beats at the second cardiac site. Another histogram parameter represents the range of values of the beat to beat time interval for the beats who'"'"'s data is included in the histogram data set. Another histogram parameter has values indicating if the beats who'"'"'s data is included in the histogram data set were acquired under conditions in which the delivery of non-excitatory ETC signals substantially affected or did not substantially affect the velocity of propagation of depolarization waves in the myocardium. Another histogram parameter, which may be used in devices having pacing capability has values indicating whether the beats who'"'"'s data is included in the histogram data set are paced beats or non-paced beats. The histogram data sets are processed for computing a set of data usable for on-line setting of the parameters of a detection time window. This set of data may then be used for operating an implanted or external ETC device operatively connected to the electrodes.

Claims

1. A method for obtaining from a patient'"'"'s heart data useful for on-line determining of the parameters of an alert time window in an excitable tissue control device, the method comprising the steps of:

detecting at a first cardiac site and at a second cardiac site of said heart electrical events associated with myocardial activation at or about said first cardiac site and said second cardiac site respectively, under a plurality of different cardiac conditions; and

using said electrical events to obtain a plurality of different histogram data sets, each histogram data set of said plurality of histogram data sets represents a cumulative time distribution histogram of electrical cardiac events detected at said second cardiac site in a plurality of cardiac beats, each histogram data set of said plurality of histogram data sets is associated with a plurality of histogram parameters, said histogram parameters have values indicative of the cardiac conditions common to said plurality of cardiac beats used to obtain said histogram data set, said histogram parameters include a sensitivity level parameter having a value indicative of the detection sensitivity level used for detecting said electrical events of said plurality of cardiac beats at said second cardiac site.

2. The method according to claim 1 further including the step of processing said plurality of histogram data sets to compute a set of data usable for on-line determination of the parameters of said alert time window.

3. The method according to claim 2 wherein said plurality of different histogram data sets obtained in said step of using is telemetrically transmitted to an analyzing unit external to the body of said patient prior to said step of processing.

4. The method according to claim 1 further including the step of telemetrically transmitting said plurality of different histogram data sets obtained in said step of using to an analyzing unit external to the body of said patient for processing said plurality of different histogram data sets to compute a set of data usable for on-line determination of the parameters of said alert time window.

5. The method according to claim 1 wherein said step of using comprises the steps of:

setting a selected value for said detection sensitivity level parameter, by selecting a value from a plurality of values indicative of the plurality of available detection sensitivity levels and performing the detecting of said electrical events at said second cardiac site using the detection sensitivity level indicated by said selected value;

updating the values of said histogram parameters in accordance with the current cardiac conditions;

selecting a histogram data set to be updated based on the current values of said plurality of histogram parameters;

triggering a data collection time interval having a first duration, said data collection time interval comprises a plurality of contiguous time bins, each bin of said plurality of time bins has a second duration smaller than said first duration, each bin of said plurality of time bins is associated with a single data element of a plurality of data elements included in said histogram data set, the value stored in a data element of said plurality of data elements represents the number of electrical events detected in a plurality of beats at said second cardiac site within said second duration of the time bin associated with said data element;

utilizing the times of detection of said electrical events at said second cardiac site within the duration of said data collection time interval to update the number of detected electrical events recorded in said plurality of data elements of said histogram data set; and

repeating said steps of setting, updating, selecting triggering and utilizing for a desired number of cardiac beats.

6. The method according to claim 5 wherein said triggering of said step of triggering a data collection time interval is associated with the delivering of a pacing pulse to said heart.

7. The method according to claim 6 wherein said second cardiac site is at or about the left ventricle of said heart, and said pacing pulse is delivered to the right ventricle of said heart.

8. The method according to claim 6 wherein said second cardiac site is at or about the left ventricle of said heart, and said pacing pulse is delivered to the right atrium of said heart.

9. The method according to claim 5 wherein said triggering of said step of triggering a data collection time interval is associated with the detecting of an electrical event related to myocardial activation at said first cardiac site.

10. The method according to claim 9 wherein said second cardiac site is at or about the left ventricle of said heart, and said electrical event is detected at or about the right ventricle of said heart.

11. The method according to claim 9 wherein said second cardiac site is at or about the left ventricle of said heart, and said electrical event is detected at or about the right atrium of said heart.

12. The method according to claim 5 wherein said selecting of said step of setting comprises randomly or pseudo-randomly selecting a value from said plurality of values indicative of a plurality of available detection sensitivity levels.

13. The method according to claim 5 wherein said selecting of said step of setting comprises selecting a single optimized value from said plurality of values based on the determining of an optimal detection sensitivity level in a data collection session occurring prior to said step of setting.

14. The method according to claim 5 wherein said selecting of said step of setting comprises selecting a value from said plurality of values in accordance with a predetermined schedule for periodically changing the detection sensitivity level, wherein said schedule is arranged to result in sufficient data being recorded for each different value of detection sensitivity level during the period of time used for data acquisition in said patient.

15. The method according to claim 5 further including the step of delivering at least one pacing pulse to said heart.

16. The method according to claim 5 further including between said step of setting and said step of updating, the step of delivering a pacing pulse to said heart.

17. The method according to claim 5 further including the step of delivering a non-excitatory excitable tissue control signal to said heart after said data collection time interval is terminated within the current beat cycle.

18. The method according to claim 1 wherein one of said plurality of histogram parameters is a cycle length category parameter, the value of said cycle length category parameter may be one of a plurality of preset values, each value of said plurality of preset values represents a predetermined range of beat to beat time intervals, and wherein the current value of said cycle length category represents a cycle length category having a first range, the current beat to beat time interval is within said first range, wherein said current beat to beat time interval is defined as the time interval between the currently detected electrical event at said first cardiac site and the electrical event detected at said first cardiac site in the cardiac beat preceding the current cardiac beat.

19. The method according to claim 18 wherein said first cardiac site is the right ventricle of said heart, said second cardiac site is the left ventricle of said heart, and said beat to beat time interval is the R-R interval computed from the time of detection of a right ventricular electrical event associated with the current cardiac beat and the time of detection of a right ventricular electrical event associated with the cardiac beat preceding said current cardiac beat.

20. The method according to claim 18 wherein said first cardiac site is the right atrium of said heart, said second cardiac site is the left ventricle of said heart, and said beat to beat time interval is the A-A interval computed from the time of detection of a right atrial electrical event associated with the current cardiac beat and the time of detection of a right atrial electrical event associated with the cardiac beat preceding said current cardiac beat.

21. The method according to claim 1 wherein one of said plurality of histogram parameters may have a value selected from a first value and a second value different than said first value,

said first value represents a first cardiac condition in which one or more excitable tissue control signals which were applied to said heart prior to the current cardiac beat did not substantially change the conduction velocity of the depolarization wave through the myocardium of said heart,

said second value represents a second cardiac condition in which one or more excitable tissue control signals which were applied to said heart prior to the current cardiac beat substantially changed the conduction velocity of the depolarization wave through the myocardium of said heart.

22. The method according to claim 1 wherein one of said plurality of histogram parameters may have a value selected from a third value and a fourth value different than said third value,

said third value represents a third cardiac condition in which the current cardiac beat is evoked by the natural pacemaker of said heart,

said fourth value represents a fourth cardiac condition in which the current cardiac beat is evoked by a pacing pulse delivered to the myocardium of said heart.

23. The method according to claim 1 wherein said step of using further includes the step of pacing said heart.

24. The method according to claim 23 wherein said step of pacing includes changing the A-V delay used for said pacing to change the ratio of paced and non-paced beats.

25. The method according to claim 24 wherein said changing of said A-V delay is performed automatically.

26. A method for obtaining from a patient'"'"'s heart data useful for on-line determining of the parameters of an alert time window in an excitable tissue control device, the method comprising the steps of:

detecting at a first cardiac site of said heart electrical events associated with myocardial activation at or about said first cardiac site under a plurality of different cardiac conditions; and

using the detection times of said electrical events to obtain a plurality of different histogram data sets, each histogram data set of said plurality of histogram data sets represents a cumulative time distribution histogram of electrical cardiac events detected at said first cardiac site in a plurality of cardiac beats, each histogram data set of said plurality of histogram data sets is associated with a plurality of histogram parameters, said histogram parameters have values indicative of the cardiac conditions common to said plurality of cardiac beats used to obtain said histogram data set, said histogram parameters include a sensitivity level parameter having a value indicative of the detection sensitivity level used for detecting said electrical events of said plurality of cardiac beats at said first cardiac site.

27. The method according to claim 26 further including the step of processing said plurality of histogram data sets to compute a set of data usable in an excitable tissue control device for determination of the parameters of said alert time window.

28. The method according to claim 27 wherein said excitable tissue control device is an implantable excitable tissue control device.

29. The method according to claim 27 wherein said excitable tissue control device is an excitable tissue control device disposed outside the body of said patient.

30. The method according to claim 26 wherein said step of using comprises the steps of:

setting a selected value for said detection sensitivity level parameter, by selecting a value from a plurality of values indicative of the plurality of available detection sensitivity levels and performing the detecting of said electrical events at said first cardiac site using the detection sensitivity level indicated by said selected value;

updating the values of said histogram parameters in accordance with the current cardiac conditions;

selecting a histogram data set to be updated based on the current values of said plurality of histogram parameters;

triggering a data collection time interval having a first duration, said data collection time interval comprises a plurality of contiguous time bins, each bin of said plurality of time bins has a second duration smaller than said first duration, each bin of said plurality of time bins is associated with a single data element of a plurality of data elements included in said histogram data set, the value stored in a data element of said plurality of data elements represents the number of electrical events detected in a plurality of beats at said first cardiac site within said second duration of the time bin associated with said data element;

utilizing the times of detection of said electrical events at said first cardiac site within the duration of said data collection time interval to update the number of detected electrical events recorded in said plurality of data elements of said histogram data set; and

repeating said steps of setting, updating, selecting triggering and utilizing for a desired number of cardiac beats.

31. The method according to claim 30 wherein said triggering of said step of triggering a data collection time interval is associated with the delivering of a pacing pulse to a second cardiac site of said heart.

32. The method according to claim 31 wherein said first cardiac site is at or about the left ventricle of said heart, and said second cardiac site is at or about the right ventricle of said heart.

33. The method according to claim 31 wherein said first cardiac site is at or about the left ventricle of said heart, and said second cardiac site is at or about the right atrium of said heart.

34. The method according to claim 30 wherein said triggering of said step of triggering a data collection time interval is associated with the detecting of an electrical event related to myocardial activation at a second cardiac site.

35. The method according to claim 34 wherein said first cardiac site is at or about the left ventricle of said heart, and said second cardiac site is at or about the right ventricle of said heart.

36. The method according to claim 34 wherein said first cardiac site is at or about the left ventricle of said heart, and said second cardiac site is at or about the right atrium of said heart.

37. The method according to claim 30 wherein said selecting of said step of setting comprises randomly or pseudo-randomly selecting a value from said plurality of values indicative of a plurality of available detection sensitivity levels.

38. The method according to claim 30 wherein said selecting of said step of setting comprises selecting a single optimized value from said plurality of values based on the determining of an optimal detection sensitivity level in a data collection session occurring prior to said step of setting.

39. The method according to claim 30 wherein said selecting of said step of setting comprises selecting a value from said plurality of values in accordance with a predetermined schedule for periodically changing the detection sensitivity level, wherein said schedule is arranged to result in sufficient data being recorded for each different value of detection sensitivity level during the period of time used for data acquisition in said patient.

40. The method according to claim 30 further including the step of delivering at least one pacing pulse to said heart.

41. The method according to claim 30 further including between said step of setting and said step of updating, the step of delivering a pacing pulse to said heart.

42. The method according to claim 30 further including the step of delivering a non-excitatory excitable tissue control signal to said heart after said data collection time interval is terminated within the current beat cycle.

43. The method according to claim 26 wherein one of said plurality of histogram parameters is a cycle length category parameter, the value of said cycle length category parameter may be one of a plurality of preset values, each value of said plurality of preset values represents a predetermined range of beat to beat time intervals, and wherein the current value of said cycle length category represents a cycle length category having a first range, the current beat to beat time interval is within said first range, wherein said current beat to beat time interval is defined as the time interval between the currently detected electrical event at a second cardiac site and the electrical event detected at said second cardiac site in the cardiac beat preceding the current cardiac beat.

44. The method according to claim 43 wherein said second cardiac site is the right ventricle of said heart, said first cardiac site is the left ventricle of said heart, and said beat to beat time interval is the R-R interval computed from the time of detection of a right ventricular electrical event associated with the current cardiac beat and the time of detection of a right ventricular electrical event associated with the cardiac beat preceding said current cardiac beat.

45. The method according to claim 43 wherein said second cardiac site is the right atrium of said heart, said first cardiac site is the left ventricle of said heart, and said beat to beat time interval is the A-A interval computed from the time of detection of a right atrial electrical event associated with the current cardiac beat and the time of detection of a right atrial electrical event associated with the cardiac beat preceding said current cardiac beat.

46. The method according to claim 26 wherein one of said plurality of histogram parameters may have a value selected from a first value and a second value different than said first value,

said first value represents a first cardiac condition in which one or more excitable tissue control signals which were applied to said heart prior to the current cardiac beat did not substantially change the conduction velocity of the depolarization wave through the myocardium of said heart,

said second value represents a second cardiac condition in which one or more excitable tissue control signals which were applied to said heart prior to the current cardiac beat substantially changed the conduction velocity of the depolarization wave through the myocardium of said heart.

47. The method according to claim 26 wherein one of said plurality of histogram parameters may have a value selected from a third value and a fourth value different than said third value,

said third value represents a third cardiac condition in which the current cardiac beat is evoked by the natural pacemaker of said heart,

said fourth value represents a fourth cardiac condition in which the current cardiac beat is evoked by a pacing pulse delivered to the myocardium of said heart.

48. The method according to claim 26 wherein said step of using further includes the step of pacing said heart.

49. The method according to claim 48 wherein said step of pacing includes changing the A-V delay used for said pacing to change the ratio of paced and non-paced beats.

50. The method according to claim 49 wherein said changing of said A-V delay is performed automatically.

51. The method according to claim 49 wherein said changing of said A-V delay is performed manually.

52. A device for obtaining from a heart of a patient data useful for on-line determining of the parameters of an alert time window in an excitable tissue control device, the device comprising:

means for detecting at a first cardiac site of said heart electrical events associated with myocardial activation at or about said first cardiac site under a plurality of different cardiac conditions;

means for delivering non-excitatory tissue control signals to said heart; and

means for processing the detection times of said electrical events to obtain a plurality of different histogram data sets, each histogram data set of said plurality of histogram data sets represents a cumulative time distribution histogram of electrical cardiac events detected at said first cardiac site in a plurality of cardiac beats, each histogram data set of said plurality of histogram data sets is associated with a plurality of histogram parameters, said histogram parameters have values indicative of the cardiac conditions common to said plurality of cardiac beats used to obtain said histogram data set, said histogram parameters include a sensitivity level parameter having a value indicative of the detection sensitivity level used by said means for detecting to detect said electrical events of said plurality of cardiac beats at said first cardiac site.

53. The device according to claim 52 further including means for processing said plurality of histogram data sets to compute a set of data usable in an excitable tissue control device for determination of the parameters of said alert time window.

54. The device according to claim 52 wherein said device is an implantable device, said device further includes means for telemetrically communicating said plurality of histogram data sets to an analyzing unit, said analyzing unit is configured for computing from said plurality of histogram data sets a set of data usable in an excitable tissue control device for determination of the parameters of said alert time window, said analyzing unit is disposed outside of the body of said patient.

55. The device according to claim 52 wherein said device is an analyzing unit disposed outside the body of said patient, said analyzing unit is operatively connectable to a plurality of electrodes implanted in or about said heart of said patient, said analyzing unit includes means for processing said plurality of histogram data sets to compute a set of data usable in an excitable tissue control device for setting the parameters of said alert time window.

56. The device according to claim 55 wherein said excitable tissue control device is said analyzing unit.

57. The device according to claim 56 wherein said analyzing unit further comprises means for pacing said heart.

58. The device according to claim 55 wherein said device is an implantable excitable tissue control device configured for telemetrically receiving said set of data and for using said set of data for setting the parameters of said alert time window.

59. The device according to claim 58 wherein said setting comprises setting the parameters of said alert time window on a beat by beat basis.

60. A device for obtaining from a patient'"'"'s heart data useful for on-line determining of the parameters of an alert time window in an excitable tissue control device, the device comprising:

a front end unit configured for detecting electrical events in a signal sensed in at least a first cardiac site of said heart, said electrical events are associated with myocardial activation at or about said at least first cardiac site under a plurality of different cardiac conditions;

a processing unit operatively connected to said front end unit, said processing unit is configured for processing the detection times of said electrical events to obtain a plurality of different histogram data sets, each histogram data set of said plurality of histogram data sets represents a cumulative time distribution histogram of electrical cardiac events detected at said first cardiac site in a plurality of cardiac beats, each histogram data set of said plurality of histogram data sets is associated with a plurality of histogram parameters, said histogram parameters have values indicative of the cardiac conditions common to said plurality of cardiac beats used to obtain said histogram data set, said histogram parameters include a sensitivity level parameter having a value indicative of the detection sensitivity level used by said front end unit to detect said electrical events of said plurality of cardiac beats at said first cardiac site;

a memory unit operatively connected to said processing unit for storing said plurality of different histogram data sets;

an excitable tissue control unit operatively coupled to said processing unit, said excitable tissue control unit is configured for controllably delivering excitable tissue control signals to said heart; and

a power source operatively connected to said front end unit, said processing unit, said memory unit, and said excitable tissue control unit for providing power thereto.

61. The device according to claim 60 wherein said device is configured for being operatively coupled to at least two electrodes implanted in said heart.

62. The device according to claim 60 wherein said device is configured for being operatively coupled to at least two electrode pairs implanted in said heart.

63. The device according to claim 60 wherein said processing unit is configured for processing said plurality of histogram data sets to compute a set of data usable in an excitable tissue control device for determination of the parameters of said alert time window.

64. The device according to claim 60 wherein said device is an implantable device, said device further includes a telemetry unit operatively connected to said processing unit for telemetrically communicating said plurality of histogram data sets to an analyzing unit, said analyzing unit is configured for computing a set of data usable in an excitable tissue control device for determination of the parameters of said alert time window, said analyzing unit is disposed outside of the body of said patient.

65. The device according to claim 64 wherein said telemetry unit of said implantable device is configured for telemetrically receiving said set of data from said analyzing unit, and wherein said processing unit is configured for storing the received set of data in said memory unit and for using said set of data for on-line determination of the parameters of said alert time window.

66. The implantable device according to claim 64 wherein said front end unit comprises one or more sense amplifier units operatively connected to one or more sensing units for sensing, said processing unit is a controller unit configured for controlling the operation of said one or more sense amplifier units, said one or more sensing units, said telemetry unit, said memory unit and said excitable tissue control unit.

67. The device according to claim 60 further including a pacing unit operatively connected to said processing unit, said pacing unit is configured for pacing at least one chamber of said heart.

68. The device according to claim 60 wherein said processing unit is configured for,

setting a selected value for said detection sensitivity level parameter, by selecting a value from a plurality of values indicative of a plurality of available detection sensitivity levels and controlling said front unit to perform the detecting of said electrical events at said first cardiac site using the detection sensitivity level indicated by said selected value,

updating the values of said histogram parameters in accordance with the current cardiac conditions,

selecting a histogram data set to be updated based on the current values of said plurality of histogram parameters,

triggering a data collection time interval having a first duration, said data collection time interval comprises a plurality of contiguous time bins, each bin of said plurality of time bins has a second duration smaller than said first duration, each bin of said plurality of time bins is associated with a single data element of a plurality of data elements included in said histogram data set, the value stored in a data element of said plurality of data elements represents the number of electrical events detected in a plurality of beats at said first cardiac site within said second duration of the time bin associated with said data element,

utilizing the times of detection of said electrical events at said at least a first cardiac site within the duration of said data collection time interval to update the number of detected electrical events recorded in said plurality of data elements of said histogram data set, and

repeating said steps of setting, updating, selecting triggering and utilizing for a desired number of cardiac beats.

69. The device according to claim 68 further including a pacing unit operatively connected to said processing unit, said pacing unit is configured for pacing at least a second cardiac site of said heart, wherein said triggering of said data collection time interval is associated with the delivering of a pacing pulse to said second cardiac site of said heart.

70. The device according to claim 69 wherein said first cardiac site is at or about the left ventricle of said heart, and said second cardiac site is the right ventricle of said heart.

71. The device according to claim 69 wherein said first cardiac site is at or about the left ventricle of said heart, and said and said second cardiac site is the right atrium of said heart.

72. The device according to claim 69 wherein one of said plurality of histogram parameters may have a value selected from a third value and a fourth value different than said third value,

said third value represents a third cardiac condition in which the current cardiac beat is evoked by the natural pacemaker of said heart,

said fourth value represents a fourth cardiac condition in which the current cardiac beat is evoked by a pacing pulse delivered to the myocardium of said heart by said pacing unit.

73. The device according to claim 69 wherein said device is configured for controllably changing the A-V delay used for pacing said heart by said pacing unit, to change the ratio of paced beats and non-paced beats.

74. The device according to claim 73 wherein said changing of said A-V delay is automatically performed by said device.

75. The device according to claim 68 wherein said front end unit is configured for detecting electrical events is a second cardiac site of said heart, and wherein said triggering of said data collection time interval by said processing unit is associated with the detecting of an electrical event associated with myocardial activation at said second cardiac site.

76. The device according to claim 75 wherein said first cardiac site is at or about the left ventricle of said heart, and said second cardiac site is at or about the right ventricle of said heart.

77. The device according to claim 75 wherein said first cardiac site is at or about the left ventricle of said heart, and said second cardiac site is at or about the right atrium of said heart.

78. The device according to claim 68 wherein said processing unit is configured for randomly or pseudo-randomly selecting a value from said plurality of values indicative of a plurality of available detection sensitivity levels, and for setting in the current cardiac beat cycle the detecting sensitivity level for detecting said electrical events at said first cardiac site in accordance with said value.

79. The device according to claim 68 wherein said processing unit is configured for selecting a single optimized value from said plurality of values, and for setting the detection sensitivity level for detecting said electrical events at said first cardiac site in accordance with said optimized value, the selection of said optimized value is based on the determining of an optimal detection sensitivity level in a data collection session performed in said patient.

80. The device according to claim 68 wherein said processing unit is configured for selecting a value from said plurality of values in accordance with a predetermined schedule for periodically changing the detection sensitivity level, wherein said schedule is arranged to result in sufficient data being recorded for each different value of detection sensitivity level during a period of time used for data acquisition in said patient.

81. The device according to claim 68 wherein said processing unit is configured for controlling said excitable tissue control unit to deliver a non-excitatory excitable tissue control signal to said heart after said data collection time interval is terminated within the current beat cycle.

82. The device according to claim 60 wherein one of said plurality of histogram parameters is a cycle length category parameter, the value of said cycle length category parameter may be one of a plurality of preset values, each value of said plurality of preset values represents a predetermined range of beat to beat time intervals, and wherein the current value of said cycle length category represents a cycle length category having a first range, the current beat to beat time interval is within said first range, wherein said current beat to beat time interval is the time interval between the currently detected electrical event at a second cardiac site and the electrical event detected at said second cardiac site in the cardiac beat preceding the current cardiac beat.

83. The device according to claim 82 wherein said second cardiac site is the right ventricle of said heart, said first cardiac site is the left ventricle of said heart, and said beat to beat time interval is the R-R interval computed from the time of detection of a right ventricular electrical event associated with the current cardiac beat and the time of detection of a right ventricular electrical event associated with the cardiac beat preceding said current cardiac beat.

84. The device according to claim 82 wherein said second cardiac site is the right atrium of said heart, said first cardiac site is the left ventricle of said heart, and said beat to beat time interval is the A-A interval computed from the time of detection of a right atrial electrical event associated with the current cardiac beat and the time of detection of a right atrial electrical event associated with the cardiac beat preceding said current cardiac beat.

85. The device according to claim 60 wherein one of said plurality of histogram parameters may have a value selected from a first value and a second value different than said first value,

said first value represents a first cardiac condition in which one or more excitable tissue control signals which were applied to said heart by said excitable tissue control unit, prior to the current cardiac beat, did not substantially change the conduction velocity of the depolarization wave through the myocardium of said heart,

said second value represents a second cardiac condition in which one or more excitable tissue control signals which were applied to said heart by said excitable tissue control unit, prior to the current cardiac beat, substantially changed the conduction velocity of the depolarization wave through the myocardium of said heart.

86. An excitable tissue control device for obtaining from a patient'"'"'s heart data collected under a plurality of different cardiac conditions, said data is useful for on-line determining of the parameters of an alert time window, said device is operatively connectable to a plurality of electrodes implanted in or about said heart, the device comprising:

detection circuitry for detecting electrical events associated with myocardial activation of a first cardiac site through at least a first electrode of said plurality of electrodes, said at least first electrode is disposed in or about said first cardiac site, and for detecting electrical events associated with myocardial activation of a second cardiac site through at least a second electrode of said plurality of electrodes, said at least second electrode is disposed in or about said second cardiac site;

an excitable tissue control unit for delivering non-excitatory excitable tissue control signals to at least part of said second cardiac site through one or more electrodes of said plurality of electrodes;

a memory unit for storing a plurality of different histogram data sets, each histogram data set of said plurality of histogram data sets represents a cumulative time distribution histogram of electrical cardiac events detected at said second cardiac site in a plurality of cardiac beats, each histogram data set of said plurality of histogram data sets is associated with a plurality of histogram parameters, said histogram parameters have values indicative of the cardiac conditions common to said plurality of cardiac beats used to obtain said histogram data set, said histogram parameters include a sensitivity level parameter having a value indicative of the detection sensitivity level used for detecting said electrical events of said plurality of cardiac beats at said second cardiac site;

a processing unit operatively connected to said detection circuitry, said excitable tissue control unit and said memory unit, for receiving detection signals from said detection circuitry, for controlling said excitable tissue control unit by using the received detection signals, and for controlling the processing and the storing of said plurality of different histogram data sets; and

a power source for providing power to said detection circuitry, said processing unit, said memory unit, and said excitable tissue control unit.

87. The device according to claim 86 further including a telemetry unit operatively connected to said power source and to said processing unit for telemetrically transmitting said plurality of different histogram data sets.

88. The device according to claim 86 wherein said detection circuitry comprises a front end unit operatively connectable to at least one electrode of said plurality of electrodes, and an analog to digital converter operatively connected to said processing unit, and wherein said detecting of said electrical events is digitally performed by said processing unit.

89. The device according to claim 86 wherein said detection circuitry comprises:

one or more sense amplifier units connectable to at least some electrodes of said plurality of electrodes, to provide one or more amplified cardiac electrical signals; and

one or more sensing units operatively connected to said one or more sense amplifiers units and to said processing unit, for detecting said electrical events in said one or more amplified cardiac electrical signals, to provide said processing unit with signals associated with the detection of said electrical events.

90. The device according to claim 86 wherein said plurality of sets of alert time window parameters of said set of data are stored in said memory unit as a data array or a look up table.

91. The device according to claim 86 wherein said detection circuitry is adapted for being controllably switched between a plurality of detection sensitivity levels.

92. The device according to claim 91 wherein said detection circuitry is adapted for being switched between a plurality of voltage threshold levels and said at least one detection sensitivity parameter is associated with a voltage threshold level.

93. The device according to claim 91 wherein said detection circuitry is adapted for performing event detection based on a morphological detection method and wherein said at least one detection sensitivity parameter is associated with at least one morphological detection parameter.

94. The device according to claim 86 wherein said plurality of cardiac conditions comprises beats having a plurality of different beat to beat time intervals representing different instantaneous heart rates of said heart.

95. The device according to claim 94 wherein said plurality of cardiac conditions further comprises beats occurring during a time period in which the prior application of excitable tissue control signals results in a change of the velocity of propagation of a depolarization wave in at least a portion of the myocardial tissue disposed between said first cardiac site and said second cardiac site of said heart, and beats occurring during a time period in which the prior application of excitable tissue control signals does not result in a change in the velocity of propagation of a depolarization wave in at least a portion of the myocardial tissue disposed between said first cardiac site and said second cardiac site of said heart.

96. The device according to claim 86 wherein said plurality of cardiac conditions comprises beats occurring during a time period in which the prior application of excitable tissue control signals results in a change of the velocity of propagation of a depolarization wave in at least a portion of the myocardial tissue disposed between said first cardiac site and said second cardiac site of said heart, and beats occurring during a time period in which the prior application of excitable tissue control signals does not result in a change in the velocity of propagation of a depolarization wave in at least a portion of the myocardial tissue disposed between said first cardiac site and said second cardiac site of said heart.

97. The device according to claim 86 further including a pacing unit operatively connected to said power source, said processing unit, said pacing unit is connectable to at least one electrode of said plurality of electrodes for delivering pacing pulses to said heart through said at least one electrode.

98. The device according to claim 97 wherein said plurality of cardiac conditions comprises beats initiated by the natural pacemaker of said heart and beats initiated by a pacing pulse delivered by said excitable tissue control device.

99. The device according to claim 98 wherein said plurality of cardiac conditions further comprise beats having a plurality of different beat to beat time intervals representing different instantaneous heart rates of said heart.

100. The device according to claim 99 wherein said plurality of cardiac conditions further comprises beats occurring during a time period in which the prior application of excitable tissue control signals results in a change of the velocity of propagation of a depolarization wave in at least a portion of the myocardial tissue disposed between said first cardiac site and said second cardiac site of said heart, and beats occurring during a time period in which the prior application of excitable tissue control signals does not result in a change in the velocity of propagation of a depolarization wave in at least a portion of the myocardial tissue disposed between said first cardiac site and said second cardiac site of said heart.

101. The device according to claim 86 wherein said first cardiac site is the right ventricle of said heart and said second cardiac site is the left ventricle of said heart.

102. The device according to claim 86 wherein said first cardiac site is the right atrium of said heart and said second cardiac site is the left ventricle of said heart.

103. The device according to claim 86 wherein said excitable tissue control device is adapted to be implanted in said patient.

104. The device according to claim 86 wherein said device is an analyzing unit disposed out of said patient, and wherein said processing unit is configured for processing said plurality of histogram data sets to compute a set of data usable in an excitable tissue control device for on-line determination of the parameters of said alert time window.

105. A system for obtaining from a patient'"'"'s heart data useful for on-line determining of the parameters of an alert time window in an excitable tissue control device, the system comprising:

an implantable excitable tissue control device operatively connectable to a plurality of electrodes implanted in or about said heart, the device includes,

detection circuitry for detecting electrical events associated with myocardial activation of a first cardiac site through at least a first electrode of said plurality of electrodes, said at least first electrode is disposed in or about said first cardiac site, and for detecting electrical events associated with myocardial activation of a second cardiac site through at least a second electrode of said plurality of electrodes, said at least second electrode is disposed in or about said second cardiac site,

an excitable tissue control unit for delivering non-excitatory excitable tissue control signals to at least part of said second cardiac site through one or more electrodes of said plurality of electrodes,

a memory unit for storing a plurality of different histogram data sets, each histogram data set of said plurality of histogram data sets represents a cumulative time distribution histogram of electrical cardiac events detected at said second cardiac site in a plurality of cardiac beats, each histogram data set of said plurality of histogram data sets is associated with a plurality of histogram parameters, said histogram parameters have values indicative of the cardiac conditions common to said plurality of cardiac beats used to obtain said histogram data set, said histogram parameters include a sensitivity level parameter having a value indicative of the detection sensitivity level used for detecting said electrical events of said plurality of cardiac beats at said second cardiac site,

a controller unit operatively connected to said detection circuitry, said excitable tissue control unit and said memory unit, for receiving detection signals from said detection circuitry, for controlling said excitable tissue control unit by using the received detection signals, and for controlling the processing and the storing of said plurality of different histogram data sets,

a power source for providing power to said detection circuitry, said processing unit, said memory unit, and said excitable tissue control unit, and

a first telemetry unit configured for telemetrically transmitting said plurality of different histogram data sets; and

an analyzing unit comprising a second telemetry unit for receiving the plurality of different histogram data sets transmitted by said first telemetry unit of said implantable excitable tissue control device, and a processing unit for processing said plurality of different histogram data sets to compute a set of data usable for on-line determination of the parameters of said alert time window.

106. The system according to claim 105 wherein said implantable excitable tissue control device further includes a pacing unit for pacing at least one chamber of said heart.

107. The system according to claim 105 wherein said second telemetry unit of said analyzing unit is a telemetry transceiver configured for transmitting at least said set of data to said implantable excitable tissue control device, and wherein said first telemetry unit of said implantable excitable tissue control device is a telemetry transceiver configured for receiving at least said set of data from said analyzing unit.

108. The system according to claim 105 wherein said analyzing unit further includes at least one user interface device operatively connected to said processing unit, said at least one user interface device is configured for controlling the operation of said analyzing unit by a user.

109. The system according to claim 105 wherein said analyzing unit further includes a display unit operatively connected to said processing unit for displaying data to a user of said system.

110. The system according to claim 105 wherein said analyzing unit further includes a data storage unit operatively connected to said processing unit for storing data received by said analyzing unit or computed by said processing unit or entered by a user of said system through a user interface device operatively connected to said analyzing unit.

111. A system for obtaining from a patient'"'"'s heart data useful for on-line determining of the parameters of an alert time window in an excitable tissue control device, the system comprising:

an implantable excitable tissue control device operatively connectable to a plurality of electrodes implanted in or about said heart, the device includes,

detecting means for detecting electrical events associated with myocardial activation of a first cardiac site through at least a first electrode of said plurality of electrodes, said at least first electrode is disposed in or about said first cardiac site, and for detecting electrical events associated with myocardial activation of a second cardiac site through at least a second electrode of said plurality of electrodes, said at least second electrode is disposed in or about said second cardiac site,

means for delivering non-excitatory excitable tissue control signals to at least part of said second cardiac site through one or more electrodes of said plurality of electrodes,

memory means for storing a plurality of different histogram data sets, each histogram data set of said plurality of histogram data sets represents a cumulative time distribution histogram of electrical cardiac events detected at said second cardiac site in a plurality of cardiac beats, each histogram data set of said plurality of histogram data sets is associated with a plurality of histogram parameters, said histogram parameters have values indicative of the cardiac conditions common to said plurality of cardiac beats used to obtain said histogram data set, said histogram parameters include a sensitivity level parameter having a value indicative of the detection sensitivity level used for detecting said electrical events of said plurality of cardiac beats at said second cardiac site,

means for controlling said detecting means, said means for delivering non-excitatory excitable tissue control signals, and said memory means, for receiving detection signals from said detecting means, for controlling said means for delivering non-excitatory excitable tissue control signals by using the received detection signals, and for controlling the processing and the storing of said plurality of different histogram data sets,

energizing means for providing power to said detecting means, said means for controlling, said memory means, and said means for delivering non-excitatory excitable tissue control signals, and

first telemetry means configured for telemetrically transmitting said plurality of different histogram data sets; and

an analyzing unit including second telemetry means for receiving the plurality of different histogram data sets transmitted by said first telemetry means of said implantable excitable tissue control device, and processing means for processing said plurality of different histogram data sets to compute a set of data usable for on-line determination of the parameters of said alert time window.