Cardiac Activation Sequence Monitoring for Ischemia Detection
First Claim
1. A system, comprising:
- a housing configured for implantation in a patient;
a plurality of implantable electrodes configured for sensing a plurality of composite signals associated with an unknown number of signal sources;
a memory provided in the housing and configured to store a baseline angular orientation of a cardiac signal vector representative of the patient'"'"'s baseline ischemia status; and
a processor provided in the housing and coupled to the electrodes and the memory, the processor configured to;
open a window associated with an ST-T segment within which the plurality of composite signals are sensed for each of a plurality of cardiac cycles;
perform recurring source separation operations by which the plurality of composite signals sensed within the window are separated according to their respective sources to produce windowed cardiac signal vectors indicating a dominant angular orientation of repolarization wavefronts over the plurality of cardiac cycles; and
detect a deviation in the dominant angular orientation of the windowed cardiac signal vectors relative to the baseline angular orientation as an indication of a change in the patient'"'"'s ischemia status relative to the patient'"'"'s baseline ischemia status.
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Abstract
Cardiac monitoring and/or stimulation methods and systems that provide one or more of monitoring, diagnosing, defibrillation, and pacing. Cardiac signal separation is employed to detect, monitor, track and/or trend ischemia using cardiac activation sequence information. Ischemia detection may involve sensing composite cardiac signals using implantable electrodes, and performing a signal separation that produces one or more cardiac activation signal vectors associated with one or more cardiac activation sequences. A change in the signal vector may be detected using subsequent separations. The change may be an elevation or depression of the ST segment of a cardiac cycle or other change indicative of myocardial ischemia, myocardial infarction, or other pathological change. The change may be used to predict, quantify, and/or qualify an event such as an arrhythmia, a myocardial infarction, or other pathologic change. Information associated with the vectors may be stored and used to track the vectors.
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Citations
22 Claims
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1. A system, comprising:
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a housing configured for implantation in a patient; a plurality of implantable electrodes configured for sensing a plurality of composite signals associated with an unknown number of signal sources; a memory provided in the housing and configured to store a baseline angular orientation of a cardiac signal vector representative of the patient'"'"'s baseline ischemia status; and a processor provided in the housing and coupled to the electrodes and the memory, the processor configured to; open a window associated with an ST-T segment within which the plurality of composite signals are sensed for each of a plurality of cardiac cycles; perform recurring source separation operations by which the plurality of composite signals sensed within the window are separated according to their respective sources to produce windowed cardiac signal vectors indicating a dominant angular orientation of repolarization wavefronts over the plurality of cardiac cycles; and detect a deviation in the dominant angular orientation of the windowed cardiac signal vectors relative to the baseline angular orientation as an indication of a change in the patient'"'"'s ischemia status relative to the patient'"'"'s baseline ischemia status. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system, comprising:
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a plurality of electrodes configured for sensing a plurality of composite signals associated with an unknown number of signal sources including physiologic and environmental noise sources; a memory configured to store baseline data of a cardiac signal vector representative of the patient'"'"'s baseline ischemia status; and a processor coupled to the electrodes and the memory, the processor configured to; open a window associated with an ST-T segment within which the plurality of composite signals are sensed for each of a plurality of cardiac cycles; perform recurring source separation operations by which the plurality of composite signals sensed within the window are separated according to their respective sources to produce windowed cardiac signal vectors indicating a feature of repolarization wavefronts over the plurality of cardiac cycles; and detect a deviation in the repolarization wavefront feature of the windowed cardiac signal vectors relative to the baseline data as an indication of a change in the patient'"'"'s ischemia status relative to the patient'"'"'s baseline ischemia status. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A system, comprising:
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a plurality of electrodes configured for sensing a plurality of composite signals associated with an unknown number of signal sources including physiologic and environmental noise sources; a memory; and a processor coupled to the electrodes and the memory, the processor configured to; open a first window associated with a P-QRS segment within which the plurality of composite signals are sensed for each of a plurality of cardiac cycles; open a second window associated with an ST-T segment within which the plurality of composite signals are sensed for each of the plurality of cardiac cycles; perform recurring source separation operations by which the plurality of composite signals sensed within the first and second windows are separated according to their respective sources to produce first and second windowed cardiac signal vectors representing a dominant angular orientation of respective depolarization and repolarization wavefronts over the plurality of cardiac cycles; determine a relationship between the angles of the first windowed vectors relative to the second windowed vectors; and detect a change in the patient'"'"'s ischemia status based on the relationship between the angles of the first windowed vectors relative to the second windowed vectors. - View Dependent Claims (20, 21, 22)
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Specification