Apparatus and method for setting the parameters of an alert window used for timing the delivery of ETC signals to a heart under varying cardiac conditions

• US 6,597,952 B1
• Filed: 02/12/2001
• Issued: 07/22/2003
• Est. Priority Date: 06/08/1999
• Status: Expired due to Term

• Current Assignee: Impulse Dynamics NV
• Original Assignee: Impulse Dynamics NV
• Inventors: Mika, Yuval, Routh, Andre G., Belsky, Ziv, Prutchi, David
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US09/782,347
• Time in Patent Office: 890 Days
• Field of Search: 600/510, 600/521, 607/9, 607/25, 607/27, 128/898
• US Class Current: 607/27
• 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 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• 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

A method for setting the parameters of an alert time window in an excitable tissue control device operative under a plurality of different cardiac conditions of a heart of a patient. The method includes providing said excitable tissue control device with a set of data including a plurality of sets of alert time window parameters. Each set of window parameters is uniquely associated with a different set of values of a plurality of cardiac condition defining parameters identifying one of the different cardiac conditions. Each set of window parameters includes at least a set of timing parameters usable for obtaining a beginning time point and an ending time point of the alert window. The sets of window parameters are obtained by processing data collected within a data collection session from a plurality of cardiac beats of the same patient under the different cardiac conditions.

Claims

1. An excitable tissue control device for setting on a beat by beat basis the parameters of an alert time window under a plurality of different cardiac conditions of a heart of a patient, 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 in a signal sensed through at least a first electrode disposed in or about said first cardiac site, and for detecting electrical events associated with myocardial activation of a second cardiac site, in a signal sensed through at least a second electrode 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 set of data, said set of data comprises a plurality of sets of alert time window parameters, each set of alert time window parameters is uniquely associated with a different set of values of a plurality of cardiac condition defining parameters identifying one of said plurality of different cardiac conditions, each set of alert time window parameters comprises at least a set of timing parameters usable for obtaining a beginning time point and an ending time point for said alert time window, each set of alert time window parameters is obtained by processing data collected from a plurality of cardiac beats of said heart of said patient under said plurality of different cardiac conditions within a data collection session performed in said patient;

a processor unit operatively connected to said detection circuitry, said excitable tissue control unit and said memory unit, for receiving signals from said detection circuitry, for controlling said excitable tissue control unit by using said signals received from said detection circuitry, for updating in a current beat cycle of said heart the values of a plurality of cardiac condition defining variables corresponding to said cardiac condition defining parameters, for automatically selecting for said current beat cycle a current set of alert time window parameters of said plurality of sets of alert time window parameters based on the current values of said cardiac condition defining variables, for applying said current set of alert time window parameters to initiate said alert time window within said current beat cycle upon detecting a first event at or about said first cardiac site, and for initiating the delivery of a delayed excitable tissue control signal at or about said second cardiac site upon detecting within the duration of said alert time window an electrical event associated with myocardial activation at or about said second cardiac site of said heart; and

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

2. The device according to claim 1 further including a telemetry unit operatively connected to said power source and said processor unit for telemetrically receiving data from a second telemetry unit disposed outside said patient.

3. The device according to claim 1 wherein said plurality of sets of alert time window parameters of said set of data are stored in said memory unit.

4. The device according to claim 3 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.

5. The device according to claim 1 wherein said detection circuitry is adapted for being controllably switched between a plurality of different detection sensitivity levels, and wherein each set of alert time window parameters of said plurality of sets of alert time window parameters further comprises at least one detection sensitivity parameter having a value representing one of said plurality of detection sensitivity levels of said detection circuitry, and wherein said processor unit is adapted for using said value of said at least one detection sensitivity parameter of said current beat cycle to switch said detection circuitry to a detection sensitivity level represented by said at least one detection sensitivity parameter of said current beat cycle.

6. The device according to claim 5 wherein said detection circuitry is adapted for being switched between a plurality of voltage threshold levels and said at least one detection sensitivity parameter comprises a voltage threshold level.

7. The device according to claim 1 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 comprises at least one morphological detection parameter.

8. The device according to claim 5 wherein said set of data is a degenerate set of data in which at least some of said sets of alert time window parameters of said plurality of sets of alert time window parameters have identical values of said at least one detection sensitivity parameter.

9. The device according to claim 1 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.

10. The device according to claim 9 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.

11. The device according to claim 1 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.

12. The device according to claim 1 further including a pacing unit operatively connected to said power source and said processor unit, said pacing unit is operatively connectable to at least one electrode of said plurality of electrodes for delivering pacing pulses to said heart through said at least one electrode.

13. The device according to claim 12 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 pacing unit.

14. The device according to claim 13 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.

15. The device according to claim 14 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.

16. The device according to claim 1 wherein said set of timing parameters of said alert time window parameters comprises a beginning time point value and an ending time point value for said alert time window.

17. The device according to claim 1 wherein said excitable tissue control device is provided with a value of the bin duration of a time bin used for collecting data within said data collection session, said value is stored in said memory unit, wherein said set of timing parameters of said alert time window parameters comprises a starting bin number and an ending bin number and wherein said processor unit is adapted for computing the starting time point and ending time point of said alert time window from said bin duration, said starting bin number and said ending bin number, prior to starting of said alert time window within said current beat cycle.

18. The device according to claim 1 wherein said set of timing parameters comprises a set of approximation parameters and wherein said processing comprises using an approximation method to process said data collected from said heart in said data collection session to obtain a plurality of sets of approximation parameters usable for computing improved approximated values of the beginning time point and the ending time point of said alert time window.

19. The device according to claim 18 wherein said approximation method is a linear piecewise approximation method, said set of approximation parameters comprises a beginning time point parameter and a first slope parameter associated with said beginning time point parameter, an ending time point parameter and a second slope parameter associated with said ending time point parameter, said using comprises computing an approximated beginning time point for said alert time window of said current beat cycle from the values of the current cycle length measured for said current beat cycle, said first slope parameter and said beginning time point parameter, and computing an approximated ending time point for said alert time window of said current beat cycle from the values of said current cycle length, said second slope parameter and said ending time point parameter.

20. The device according to claim 19 wherein said current cycle length is the instantaneous cycle length determined from the current R—

R interval or the current A—

A interval measured for said current beat cycle.

21. The device according to claim 19 wherein said current cycle length is an average cycle length computed from the values of a plurality of consecutive R—

R intervals including the R—

R interval of said current beat cycle.

22. The device according to claim 19 wherein said current cycle length is an average cycle length computed from the values of a plurality of consecutive A—

A intervals including the A—

A interval of said current beat cycle.

23. The device according to claim 1 wherein said set of timing parameters comprises said beginning time point and said ending time point of said alert time window.

24. The device according to claim 1 wherein said set of data is a degenerate set of data in which at least some of said sets of alert time window parameters of said plurality of sets of alert time window parameters have identical values of said set of timing parameters.

25. The device according to claim 1 wherein said first cardiac site is the right ventricle of said heart and said second cardiac site is the left ventricle of said heart.

26. The device according to claim 1 wherein said first cardiac site is the right atrium of said heart and said second cardiac site is the left ventricle of said heart.

27. The device according to claim 1 wherein said excitable tissue control device is an implantable device.

28. The device according to claim 1 wherein said excitable tissue control device is adapted for being disposed out of said patient and is operatively connectable to said plurality of electrodes.

29. The device according to claim 1 wherein said detection circuitry comprises:

at least a first sense amplifier connectable to said at least first electrode for amplifying an electrical signal sensed through said at least first electrode to generate a first amplified signal;

at least a second sense amplifier connectable to said at least second electrode for amplifying an electrical signal sensed through said at least second electrode to generate a second amplified signal;

at least a first sensing unit operatively connected to said at least first sense amplifier and to said processing unit, for detecting in said first amplified signal electrical events associated with myocardial activation of said first cardiac site and for providing said processing unit with trigger signals indicative of an electrical event associated with myocardial activation of said first cardiac site detected in said first amplified signal; and

at least a second sensing unit operatively connected to said at least second sense amplifier and to said processing unit, for detecting in said second amplified signal electrical events associated with myocardial activation of said second cardiac site and for providing said processing unit with trigger signals indicative of an electrical event associated with myocardial activation of said second cardiac site detected in said second amplified signal.

30. The device according to claim 29 wherein said processing unit is a controller unit.

31. An excitable tissue control device for setting on a beat by beat basis the parameters of an alert time window under a plurality of different cardiac conditions of a heart of a patient, the device is operatively connectable to a plurality of electrodes implanted in or about said heart, the device comprising:

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;

excitable tissue control 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 set of data, said set of data comprises a plurality of sets of alert time window parameters, each set of alert time window parameters is uniquely associated with a different set of values of a plurality of cardiac condition defining parameters identifying one of said plurality of different cardiac conditions, each set of alert time window parameters comprises at least a set of timing parameters usable for obtaining a beginning time point and an ending time point for said alert time window, each set of alert time window parameters is obtained by processing data collected from a plurality of cardiac beats of said heart of said patient under said plurality of different cardiac conditions within a data collection session performed in said patient;

processing means operatively connected to said detection means, said excitable tissue control means and said memory means, for receiving detection signals from said detection means, for controlling said excitable tissue control means by using the received detection signals, for updating in a current beat cycle of said heart the values of a plurality of cardiac condition defining variables corresponding to said cardiac condition defining parameters, for automatically selecting for said current beat cycle a current set of alert time window parameters of said plurality of sets of alert time window parameters based on the current values of said cardiac condition defining variables, for applying said current set of alert time window parameters to initiate said alert time window within said current beat cycle upon detecting an electrical event associated with myocardial activation at or about said first cardiac site, and for initiating the delivery of a delayed excitable tissue control signal at or about said second cardiac site upon detecting within the duration of said alert time window an electrical event associated with myocardial activation at or about said second cardiac site of said heart; and

energizing means for providing power to at least said detection means, said processing means said memory means and said excitable tissue control means.

32. The device according to claim 31 further including telemetry means operatively connected to said energizing means and said processing means for telemetrically receiving data from a second telemetry means disposed outside said patient.

33. The device according to claim 31 further including means for pacing said heart, said means for pacing is operatively connected to said energizing means, said processing means and to at least one electrode of said plurality of electrodes, said means for pacing is configured for delivering pacing pulses to at least one chamber of said heart through said at least one electrode.

34. An excitable tissue control device for setting on a beat by beat basis the parameters of an alert time window under a plurality of different cardiac conditions of a heart of a patient, the device is operatively connectable to a plurality of electrodes implanted in or about said heart, the device comprising:

means for detecting electrical events associated with myocardial activation of a first cardiac site of said heart, and for detecting electrical events associated with myocardial activation of a second cardiac site of said heart;

means for delivering non-excitatory excitable tissue control signals to at least part of said second cardiac site;

means for storing a set of data, said set of data comprises a plurality of sets of alert time window parameters, each set of alert time window parameters is uniquely associated with a different set of values of a plurality of cardiac condition defining parameters identifying one of said plurality of different cardiac conditions, each set of alert time window parameters comprises at least a set of timing parameters usable for obtaining a beginning time point and an ending time point for said alert time window;

means for processing, operatively connected to said means for detecting, said means for delivering non-excitatory excitable tissue control signals, and said means for storing, said means for processing is configured for receiving detection signals associated with the detecting of said electrical events from said means for detecting, for controlling said means for delivering non-excitatory excitable tissue control signals by using said detection signals, for updating in a current beat cycle of said heart the values of a plurality of cardiac condition defining variables corresponding to said cardiac condition defining parameters, for automatically selecting for said current beat cycle a current set of alert time window parameters of said plurality of sets of alert time window parameters based on the current values of said cardiac condition defining variables, for applying said current set of alert time window parameters to initiate said alert time window within said current beat cycle upon detecting a first electrical event associated with myocardial activation at or about said first cardiac site, and for controlling the delivery of a delayed excitable tissue control signal, by said means for delivering non-excitatory excitable tissue control signals, at or about said second cardiac site upon detecting, within the duration of said alert time window, an electrical event associated with myocardial activation at or about said second cardiac site of said heart; and

means for providing power to at least said means for detecting, said means for processing, said means for storing, and said means for delivering non-excitatory excitable tissue control signals.

35. The device according to claim 34, wherein at least one set of alert window parameters of said plurality of sets of alert time window parameters is obtained by processing data collected from a plurality of cardiac beats of said heart of said patient under said plurality of different cardiac conditions within a data collection session performed in said patient.

36. The device according to claim 34 further including means for telemetrically receiving signals, operatively connected to said means for providing power and to said means processing, said means for telemetrically receiving signals is configured for telemetrically receiving data from a second telemetry means disposed outside said patient.

37. The device according to claim 34 further including means for pacing said heart, said means for pacing is operatively connected to said means for providing power, said means for processing, and to at least one electrode of said plurality of electrodes, said means for pacing is configured for delivering pacing pulses to at least one chamber of said heart through said at least one electrode.

38. An excitable tissue control device for setting on a beat by beat basis the parameters of an alert time window under a plurality of different cardiac conditions of a heart of a patient, the device is operatively connectable to a plurality of electrodes implanted in or about said heart, the device comprising:

a detecting unit for detecting electrical events associated with myocardial activation of a first cardiac site of said heart, and for detecting electrical events associated with myocardial activation of a second cardiac site of said heart;

an excitable tissue control unit for delivering non-excitatory excitable tissue control signals to at least part of said second cardiac site;

a memory unit for storing a set of data, said set of data comprises a plurality of sets of alert time window parameters, each set of alert time window parameters is uniquely associated with a different set of values of a plurality of cardiac condition defining parameters identifying one of said plurality of different cardiac conditions, each set of alert time window parameters comprises at least a set of timing parameters usable for obtaining a beginning time point and an ending time point for said alert time window;

a processing unit, operatively connected to said detecting unit, said excitable tissue control unit, and said memory unit, said processing unit is configured for receiving from said detecting unit detection signals associated with the detecting of said electrical events, for controlling said excitable tissue control unit by using said detection signals, for updating in a current beat cycle of said heart the values of a plurality of cardiac condition defining variables corresponding to said cardiac condition defining parameters, for automatically selecting for said current beat cycle a current set of alert time window parameters of said plurality of sets of alert time window parameters based on the current values of said cardiac condition defining variables, for applying said current set of alert time window parameters to initiate said alert time window within said current beat cycle upon detecting a first electrical event associated with myocardial activation at or about said first cardiac site, and for controlling the delivery of a delayed excitable tissue control signal, by said excitable tissue control unit, at or about said second cardiac site upon detecting within the duration of said alert time window an electrical event associated with myocardial activation at or about said second cardiac site of said heart; and

a power source, operatively connected to at least said detecting unit, said processing unit, said memory unit, and said excitable tissue control unit, for providing power thereto.

39. The device according to claim 38, wherein at least one set of alert window parameters of said plurality of sets of alert time window parameters is obtained by processing data collected from a plurality of cardiac beats of said heart of said patient under said plurality of different cardiac conditions within a data collection session performed in said patient.

40. The device according to claim 38 further including a telemetry unit, operatively connected to said power source and to said processing unit, for telemetrically receiving data from a second telemetry unit disposed outside said patient.

41. The device according to claim 38 further including a pacing unit operatively connected to said power source, said processing unit, and to at least one electrode of said plurality of electrodes, for delivering pacing pulses to at least one chamber of said heart through said at least one electrode.

42. An excitable tissue control device for setting on a beat by beat basis the parameters of an alert time window under a plurality of different cardiac conditions of a heart of a patient, said device is operatively connectable to a plurality of electrodes implanted in or about said heart, the device comprising:

sensing circuitry for sensing electrical events associated with myocardial activation of a first cardiac site in a signal sensed through at least a first electrode disposed in or about said first cardiac site, and for sensing electrical events associated with myocardial activation of a second cardiac site, in a signal sensed through at least a second electrode 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 set of data, said set of data comprises a plurality of sets of alert time window parameters, each set of alert time window parameters is uniquely associated with a different set of values of a plurality of cardiac condition defining parameters identifying one of said plurality of different cardiac conditions, each set of alert time window parameters comprises at least a set of timing parameters usable for obtaining a beginning time point and an ending time point for said alert time window, each set of alert time window parameters is obtained by processing data collected from a plurality of cardiac beats of said heart of said patient under said plurality of different cardiac conditions within a data collection session performed in said patient;

a processor unit operatively connected to said sensing circuitry, said excitable tissue control unit and said memory unit, for receiving signals from said sensing circuitry, for processing said signals received from said sensing circuitry to detect electrical events associated with myocardial activation at said first cardiac site and at said second cardiac site, for controlling said excitable tissue control unit based on the detection of said electrical events, for updating in a current beat cycle of said heart the values of a plurality of cardiac condition defining variables corresponding to said cardiac condition defining parameters, for automatically selecting for said current beat cycle a current set of alert time window parameters of said plurality of sets of alert time window parameters based on the current values of said cardiac condition defining variables, for applying said current set of alert time window parameters to initiate said alert time window within said current beat cycle after detecting a first electrical event associated with myocardial activation at or about said first cardiac site, and for initiating the delivery of a delayed excitable tissue control signal to said second cardiac site upon detecting within the duration of said alert time window an electrical event associated with myocardial activation at or about said second cardiac site of said heart; and

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

43. The device according to claim 42 wherein said sensing circuitry comprises:

a front end unit connectable to said at least first electrode for pre-conditioning an electrical signal sensed through said at least first electrode to generate a first pre-conditioned signal, said front end unit is also connectable to said at least second electrode for pre-conditioning an electrical signal sensed through said at least second electrode to generate a second pre-conditioned signal; and

at least one analog to digital converter unit operatively connected to said front end unit and to said processing unit, for receiving said first pre-conditioned signal and said second pre-conditioned signal from said front end unit and for digitizing said first pre-conditioned signal and said second pre-conditioned signal, to provide digitized signals to said processing unit.

44. The device according to claim 43 wherein the combination of said sensing circuitry and said processing unit is operative as a detection unit configured for being controllably switched between a plurality of different detection sensitivity levels, and wherein each set of alert time window parameters of said plurality of sets of alert time window parameters further comprises at least one detection sensitivity parameter having a value representing one of said plurality of detection sensitivity levels of said detection unit, and wherein said processor unit is adapted for using said value of said at least one detection sensitivity parameter of said current beat cycle to switch said detection unit to a detection sensitivity level represented by said at least one detection sensitivity parameter of said current beat cycle.

45. The device according to claim 44 wherein said detection unit is adapted for being switched between a plurality of voltage threshold levels and said at least one detection sensitivity parameter comprises a voltage threshold level.

46. The device according to claim 44 wherein said detection unit is adapted for performing event detection based on a morphological detection method and wherein said at least one detection sensitivity parameter comprises at least one morphological detection parameter.