Cardiac activation sequence monitoring for ischemia detection
First Claim
1. A method, comprising:
- sensing a plurality of composite signals using a plurality of implantable electrodes over a plurality of cardiac cycles, each of the composite signals sensed within a window associated with a cardiac sequence feature that is opened for each cycle of the plurality of cardiac cycles, wherein the electrodes are distributed between a can and at least one lead, and the can and the lead are configured for implantation;
performing a source separation using the sensed plurality of composite signals, by which the sensed plurality of composite signals are separated according to their respective sources and one or more cardiac signal vectors are produced, each of the cardiac signal vectors representing angular orientation of a wavefront of the cardiac sequence feature of a respective cardiac cycle of the plurality of cardiac cycles;
determining a baseline angular orientation of the cardiac signal vectors for the plurality of cardiac cycles;
monitoring angular orientation of one or more additional cardiac signal vectors produced by source separation of subsequent composite signals sensed within one or more detection windows associated with the cardiac sequence feature, the subsequent composite signals sensed subsequent to the sensing of the plurality of composite signals; and
detecting a deviation in angular orientation of the one or more additional cardiac signal vectors from the baseline, wherein at least one of the steps of performing, determining, monitoring, and detecting is implemented at least in part by a circuit.
1 Assignment
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Accused Products
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
29 Claims
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1. A method, comprising:
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sensing a plurality of composite signals using a plurality of implantable electrodes over a plurality of cardiac cycles, each of the composite signals sensed within a window associated with a cardiac sequence feature that is opened for each cycle of the plurality of cardiac cycles, wherein the electrodes are distributed between a can and at least one lead, and the can and the lead are configured for implantation; performing a source separation using the sensed plurality of composite signals, by which the sensed plurality of composite signals are separated according to their respective sources and one or more cardiac signal vectors are produced, each of the cardiac signal vectors representing angular orientation of a wavefront of the cardiac sequence feature of a respective cardiac cycle of the plurality of cardiac cycles; determining a baseline angular orientation of the cardiac signal vectors for the plurality of cardiac cycles; monitoring angular orientation of one or more additional cardiac signal vectors produced by source separation of subsequent composite signals sensed within one or more detection windows associated with the cardiac sequence feature, the subsequent composite signals sensed subsequent to the sensing of the plurality of composite signals; and detecting a deviation in angular orientation of the one or more additional cardiac signal vectors from the baseline, wherein at least one of the steps of performing, determining, monitoring, and detecting is implemented at least in part by a circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system, comprising:
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a plurality of implantable electrodes configured for sensing a plurality of composite signals, thereby providing a plurality of composite signals; a housing configured for implantation in a patient; a memory provided in the housing; and a controller provided in the housing and coupled to the memory and the plurality of implantable electrodes, the controller configured to; open a window associated with a cardiac sequence feature in which is sensed the plurality of composite signals for each of a plurality of cardiac cycles; perform a source separation using the sensed plurality of composite signals by which the plurality of composite signals are separated according to their respective sources to produce cardiac signal vectors representing angular orientation of wavefronts of the cardiac sequence feature over the plurality of cardiac cycles; determine a baseline angular orientation of the cardiac signal vectors for the plurality of cardiac cycles; monitor angular orientation of one or more additional cardiac signal vectors produced by source separation of subsequent composite signals sensed within one or more detection windows associated with the cardiac sequence feature, the subsequent composite signals sensed subsequent to the sensing of the plurality of composite signals; and detect a deviation in angular orientation of the one or more cardiac signal vectors from the baseline as an indication of ischemia. - View Dependent Claims (14, 15, 16, 17, 18, 19, 24, 25, 26)
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20. An implantable cardiac device, comprising:
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means for implantably sensing a plurality of composite signals over a plurality of cardiac cycles, each of the composite signals sensed within a window associated with a cardiac sequence feature that is opened for each cycle of the plurality of cardiac cycles; means for performing a source separation using the sensed plurality of composite signals by which the sensed plurality of composite signals are separated according to their respective sources, the source separation producing one or more cardiac signal vectors, each of the cardiac signal vectors representing angular orientation of a wavefront of the cardiac sequence feature of a respective cardiac cycle of the plurality of cardiac cycles; means for determining a baseline angular orientation of the cardiac signal vectors for the plurality of cardiac cycles; means for monitoring angular orientation of one or more additional cardiac signal vectors produced by source separation of subsequent composite signals sensed within one or more detection windows associated with the cardiac sequence feature, the subsequent composite signals sensed subsequent to the sensing of the plurality of composite signals; and means for detecting ischemia based on a deviation in angular orientation of the one or more additional cardiac signal vectors from the baseline. - View Dependent Claims (21, 22, 23)
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27. A method, comprising:
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sensing a plurality of composite signals using a plurality of implantable electrodes over a plurality of cardiac cycles, each of the composite signals sensed within a window associated with a cardiac sequence feature that is opened for each cycle of the plurality of cardiac cycles; performing a source separation using the sensed plurality of composite signals, by which the sensed plurality of composite signals are separated according to their respective sources to produce one or more cardiac signal vectors, each of the cardiac signal vectors representing angular orientation of a wavefront of the cardiac sequence feature of a respective cardiac cycle of the plurality of cardiac cycles; determining a baseline angular orientation of the cardiac signal vectors for the plurality of cardiac cycles; monitoring angular orientation of one or more additional cardiac signal vectors produced by source separation of subsequent composite signals sensed within one or more detection windows associated with the cardiac sequence feature, the subsequent composite signals sensed subsequent to the sensing of the plurality of composite signals; and detecting a change in angular orientation of the one or more additional cardiac signal vectors relative to the baseline, wherein at least one of the steps of performing, determining, monitoring, and detecting is implemented at least in part by a circuit. - View Dependent Claims (28, 29)
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Specification