Cardiac rhythm management systems and methods using multiple morphology templates for discriminating between rhythms
First Claim
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1. A machine-readable medium including instructions that, when performed by a machine, cause the machine to:
- obtain a first reference morphological template from a subject'"'"'s heart in the absence of an arrhythmia, while the subject is resting or inactive;
obtain a second reference morphological template from the heart under a condition different from that of the first morphological template;
obtain at least one current cardiac complex;
determine a degree of correlation between the at least one cardiac complex and at least one of the first and second morphological templates; and
declare one of first and second rhythm states at least in part using the determined degree of correlation.
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Abstract
This document describes systems, devices, and methods that use multiple morphology templates for discriminating between rhythms, such as supraventricular tachyarrhythmias (SVTs) and ventricular tachyarrhythmias (VTs), for delivering a countershock in response to a VT episode, but withholding delivery of such a countershock in response to an SVT episode. In certain examples, the particular morphology used for storing morphological features is selected at least in part using a sensor-indicated activity level of a subject, or a metabolic need of the subject.
193 Citations
21 Claims
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1. A machine-readable medium including instructions that, when performed by a machine, cause the machine to:
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obtain a first reference morphological template from a subject'"'"'s heart in the absence of an arrhythmia, while the subject is resting or inactive; obtain a second reference morphological template from the heart under a condition different from that of the first morphological template; obtain at least one current cardiac complex; determine a degree of correlation between the at least one cardiac complex and at least one of the first and second morphological templates; and declare one of first and second rhythm states at least in part using the determined degree of correlation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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obtaining a first reference morphological template from a subject'"'"'s heart in the absence of an arrhythmia, while the subject is resting or inactive; obtaining a second reference morphological template from the heart during high-rate atrial pacing; obtaining at least one current cardiac complex; determining a degree of correlation between the at least one cardiac complex and at least one of the first and second morphological templates; and declaring one of a first and second rhythm state at least in part using the determined degree of correlation. - View Dependent Claims (12)
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13. A method comprising:
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obtaining a first reference morphological template from a subject'"'"'s heart in the absence of an arrhythmia, while the subject is resting or inactive; obtaining a second reference morphological template from the heart during exercise; obtaining at least one current cardiac complex; determining a degree of correlation between the at least one cardiac complex and at least one of the first and second morphological templates; and declaring one of a first and second rhythm state at least in part using the determined degree of correlation. - View Dependent Claims (14)
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15. A method comprising:
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obtaining a first reference morphological template from a subject'"'"'s heart in the absence of an arrhythmia, while the subject is resting or inactive; obtaining a second reference morphological template, in which the second template is obtained from historical electrogram data of an episode of supraventricular tachyarrhythmia; obtaining at least one current cardiac complex; determining a degree of correlation between the at least one cardiac complex and at least one of the first and second morphological templates; and declaring one of a first and second rhythm state at least in part using the determined degree of correlation. - View Dependent Claims (16)
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17. A system comprising:
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an electrogram sensing circuit, configured to receive first and second intrinsic cardiac signals, the electrogram sensing circuit configured to provide cardiac complexes, each cardiac complex having a morphology, and an indication of heart rate obtained from the first intrinsic cardiac signal; a sensor, including a sensor output indicative of activity or metabolic need of the subject; a stored first reference morphological template, coupled to the electrogram sensing circuit, the stored first morphological template obtained from the heart in the absence of an arrhythmia while the subject is resting or inactive; a stored second reference morphological template, coupled to the electrogram sensing circuit and the sensor, the stored second morphological template obtained from the heart under a different sensor output condition from that of the first morphological template; a correlation module, coupled to the electrogram sensing circuit and the first and second morphological templates, the correlation module configured to declare an indication of one of a first and a second rhythm state, including discriminating between the first and second rhythm states using a comparison of a morphology of at least one current cardiac complex of the second intrinsic cardiac signal to at least one of the first and second morphological templates, the at least one of the first and second morphological templates selected using the indication of heart rate provided by the electrogram sensing circuit; and a template updating control module, coupled to the second morphological template and the correlation module, the template updating control module configured to provide an updated exercise template to the correlation module if;
(a) a first exercise template is not available to the correlation module or (b) an available exercise template is insufficiently correlated to the at least one cardiac complex of the intrinsic cardiac signal. - View Dependent Claims (18, 19)
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20. A method comprising:
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obtaining a first reference morphological template from a subject'"'"'s heart in the absence of an arrhythmia, while the subject is resting or inactive; obtaining a second reference morphological template from the heart under a condition different from that of the first morphological template; obtaining at least one current cardiac complex; determining a degree of correlation between the at least one cardiac complex and at least one of the first and second morphological templates; declaring one of a first and second rhythm state at least in part using the determined degree of correlation; and updating the second morphological template if the cardiac complex is not sufficiently correlated to at least one of the first and second morphological templates.
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21. A system comprising:
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means for obtaining a first reference morphological template from a subject'"'"'s heart in the absence of an arrhythmia, while the subject is resting or inactive; means for obtaining a second reference morphological template from the heart under a condition different from that of the first morphological template; means for obtaining at least one current cardiac complex; means for determining a degree of correlation between the at least one cardiac complex and at least one of the first and second morphological templates; means for declaring one of first and second rhythm states at least in part using the determined degree of correlation; and means for updating at least one of the first and second morphological templates.
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Specification