Cardiac activation sequence monitoring and tracking

• US 20060069322A1
• Filed: 09/30/2004
• Published: 03/30/2006
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: McCabe, Aaron, Meyer, Scott A., Stahmann, Jeffrey E., Zhang, Yi, Yu, Yinghong, Ricci, Carlos Alberto
• Granted Patent: US 7,890,159 B2
• Time in Patent Office: Days
• US Class Current: 600/512
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal

Abstract

Cardiac monitoring and/or stimulation methods and systems provide monitoring, diagnosis, and defibrillation and/or pacing therapies. A signal processor receives a plurality of composite signals associated with a plurality of sources, performs a source separation, and produces one or more cardiac signal vectors associated with all or a portion of one or more cardiac activation sequences based on the source separation. A method of signal separation involves detecting a change in a characteristic of the cardiac signal vector relative to a baseline. One or more vectors and/or activation sequences may be selected, and information associated with the vectors and/or activation sequences may be stored and tracked.

Claims

1. A cardiac method, comprising:

sensing a plurality of composite cardiac signals at a plurality of patient-internal locations;

performing a source separation using the sensed plurality of composite signals; and

producing one or more cardiac signal vectors associated with all or a portion of one or more cardiac activation sequences based on the source separation.

2. The method of claim 1, comprising detecting a change in a characteristic of the one or more cardiac signal vectors relative to a baseline of the one or more cardiac signal vectors.

3. The method of claim 2, wherein the baseline comprises information established by an initial source separation, and the change is detected using a subsequent source separation.

4. The method of claim 2, wherein the change detected comprises one or more of an angle change of the one or more cardiac signal vectors, a magnitude change of the one or more cardiac signal vectors, a variance change of the one or more cardiac signal vectors, a power spectral density change of the angle of the one or more cardiac signal vectors, a power spectral density change of the magnitude of the one or more cardiac signal vectors, a trajectory change of the one or more cardiac signal vectors, an activation velocity change, and a temporal profile change of the one or more cardiac signal vectors.

5. The method of claim 2, wherein the change detected comprises one or more of a rate of change of angle of the one or more cardiac signal vectors, a rate of change of magnitude of the one or more cardiac signal vectors, a rate of change of variance of the one or more cardiac signal vectors, a rate of change of velocity of the one or more cardiac signal vectors and a rate of change of temporal profile of the one or more cardiac signal vectors.

6. The method of claim 2, wherein the change detected comprises one or more of a trend of the angle of the one or more cardiac signal vectors, a trend of the magnitude of the one or more cardiac signal vectors, a trend of the variance of the one or more cardiac signal vectors, a trend of the velocity of the one or more cardiac signal vectors and a trend of the temporal profile of the one or more cardiac signal vectors.

7. The method of claim 2, wherein the change is detected using a window configured to enhance a morphological feature of the plurality of composite cardiac signals.

8. The method of claim 2, wherein the detected change is used to detect anomalous cardiac activity.

9. The method of claim 2, comprising one or more of initiating, adjusting, optimizing and terminating treatment for one or more of a disease and a condition in response to detecting the change.

10. The method of claim 9, wherein the treatment comprises one or more of bradycardia therapy, tachycardia therapy, cardiac resynchronization therapy, neural stimulation therapy, vascular intervention therapy, and pharmacologic therapy.

11. The method of claim 2, wherein the detected change is used to trigger an alert.

12. The method of claim 2, wherein the detected change is used to diagnose a cardiac disease or condition.

13. The method of claim 2, wherein the baseline comprises clinically established characteristics.

14. The method of claim 1, wherein the one or more cardiac activation sequences are indicative of a predetermined period of a plurality of cardiac cycles.

15. The method of claim 1, wherein the one or more cardiac activation sequences are indicative of a plurality of cardiac cycles.

16. The method of claim 1, wherein the one or more cardiac activation sequences are indicative of a QRS complex of a cardiac cycle.

17. The method of claim 1, wherein the one or more cardiac activation sequences are indicative of a P wave of a cardiac cycle.

18. The method of claim 1, wherein the one or more cardiac activation sequences are indicative of a T wave of a cardiac cycle.

19. The method of claim 1, wherein the one or more cardiac activation sequences are indicative of an ST segment of a cardiac cycle.

20. The method of claim 1, comprising storing information associated with the one or more cardiac signal vectors.

21. The method of claim 1, comprising transmitting information associated with the one or more cardiac signal vectors to a patient-external device.

22. The method of claim 1, comprising:

acquiring information associated with one or more of a patient'"'"'s posture, activity, movement, heart-rate, heart rhythm, respiration, blood-pressure, blood gas concentration, blood chemistry, temperature, heart-sound, cardiac output, cardiac stroke volume, cardiac wall motion, peripheral or pulmonary fluid status, autonomic system status, thoracic impedance, and heart-rate variability; and

using the acquired information to interpret the one or more cardiac signal vectors.

23. A method, comprising:

sensing, at least in part implantably, a plurality of composite cardiac signals using a plurality of electrodes;

performing a source separation using the detected plurality of composite signals, the source separation producing a plurality of vectors;

selecting one or more vectors from the plurality of vectors;

storing information associated with the selected one or more vectors; and

using the stored information to track the selected one or more vectors.

24. The method of claim 23, wherein tracking the selected one or more vectors comprises determining a cardiac activation sequence.

25. The method of claim 23, wherein selecting the one or more vectors from the plurality of vectors comprises selecting the vector having the largest power spectral density from the plurality of vectors.

26. The method of claim 23, wherein the plurality of composite signals are sensing using a far-field sense vector.

27. The method of claim 23, comprising:

performing a subsequent source separation using a plurality of subsequently detected composite signals from the plurality of cardiac electrodes; and

detecting a change in the selected one or more vectors.

28. A cardiac system, comprising:

a plurality of implantable electrodes configured for sensing a composite signal, thereby providing a plurality of composite signals;

a housing configured for implantation in a patient;

a controller provided in the housing;

a signal processor; and

a memory coupled to the signal processor;

wherein the signal processor is configured to perform a source separation using the sensed plurality of composite signals, the source separation producing one or more cardiac signal vectors associated with all or a portion of one or more cardiac activation sequences, and to store vector information in the memory.

29. The system of claim 28, wherein the signal processor is provided in a patient-external device or system, the signal processor and the controller coupled to respective communication devices to facilitate wireless communication between the signal processor and controller.

30. The system of claim 28, wherein the controller detects a cardiac condition using the vector information.

31. The system of claim 28, comprising a lead configured for subcutaneous non-intrathoracic placement in a patient and coupled to the controller, wherein at least one of the plurality of electrodes is supported by the lead.

32. The system of claim 28, wherein the plurality of electrodes comprise at least four electrodes, wherein one of the at least four electrodes does not lie in the same plane as the other of the at least four electrodes.

33. The system of claim 28, comprising one or more sensors configured to measure one or more of a patient'"'"'s posture, activity, movement, heart-rate, heart rhythm, respiration, blood-pressure, blood gas concentration, blood chemistry, temperature, heart-sound, cardiac output, cardiac stroke volume, cardiac wall motion, peripheral or pulmonary fluid status, autonomic system status, thoracic impedance, and heart-rate variability, wherein information from the one or more sensors is used to interpret the one or more cardiac signal vectors.

34. An implantable cardiac device, comprising:

means for sensing, at least in-part implantably, a plurality of composite signals using a plurality of cardiac electrodes; and

means for performing a source separation using the sensed plurality of composite signals, the source separation producing one or more cardiac signal vectors associated with all or a portion of one or more cardiac activation sequences.

35. The device of claim 34, comprising means for detecting a change in a characteristic of the one or more cardiac signal vectors relative to a baseline.

36. The device of claim 35, comprising means for detecting a cardiac disease or condition using the change in the characteristic.

37. A cardiac method, comprising:

sensing a plurality of composite cardiac signals at a plurality of patient-internal locations;

performing, patient-internally, a source separation using the sensed plurality of composite signals; and

producing, patient-internally, one or more cardiac signal vectors associated with all or a portion of one or more cardiac activation sequences based on the source separation.

38. A cardiac system, comprising:

a plurality of implantable electrodes configured for sensing a composite signal, thereby providing a plurality of composite signals;

a housing configured for implantation in a patient;

a controller provided in the housing and coupled to the plurality of implantable electrodes; and

a memory provided in the housing and coupled to the controller;

wherein the controller is configured to perform a source separation using the sensed plurality of composite signals, the source separation producing one or more cardiac signal vectors associated with all or a portion of one or more cardiac activation sequences, and to store vector information in the memory.