System and method for distinguishing among cardiac ischemia, hypoglycemia and hyperglycemia using an implantable medical device
First Claim
1. A method for use with an implantable medical device for detecting hyperglycemia in a patient in which the device is implanted, the method comprising:
- tracking repolarization peak-based intervals representative of intervals between depolarization events and peaks of corresponding repolarization events within electrical cardiac signals;
tracking repolarization end-based intervals representative of intervals between depolarization events and ends of corresponding repolarization events within electrical cardiac signals;
tracking elevations of segments of the cardiac signals between depolarization events and corresponding repolarization events; and
detecting an episode of hyperglycemia based on a change in the elevations of the segments in combination with a lack of change in the repolarization peak-based intervals and the repolarization end-based intervals.
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Accused Products
Abstract
Techniques are described for detecting ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. Ischemia is detected based on a shortening of the interval between the QRS complex and the end of a T-wave (QTmax), alone or in combination with a change in ST segment elevation. Alternatively, ischemia is detected based on a change in ST segment elevation combined with minimal change in the interval between the QRS complex and the end of the T-wave (QTend). Hypoglycemia is detected based on a change in ST segment elevation along with a lengthening of either QTmax or QTend. Hyperglycemia is detected based on a change in ST segment elevation along with minimal change in QTmax and in QTend. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by ischemia.
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Citations
14 Claims
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1. A method for use with an implantable medical device for detecting hyperglycemia in a patient in which the device is implanted, the method comprising:
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tracking repolarization peak-based intervals representative of intervals between depolarization events and peaks of corresponding repolarization events within electrical cardiac signals; tracking repolarization end-based intervals representative of intervals between depolarization events and ends of corresponding repolarization events within electrical cardiac signals; tracking elevations of segments of the cardiac signals between depolarization events and corresponding repolarization events; and detecting an episode of hyperglycemia based on a change in the elevations of the segments in combination with a lack of change in the repolarization peak-based intervals and the repolarization end-based intervals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A system for use with an implantable medical device for detecting hyperglycemia in a patient in which the device is implanted comprising:
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a timing unit operative to track repolarization peak-based intervals representative of intervals between depolarization events and peaks of corresponding repolarization events within electrical cardiac signals, to track repolarization end-based intervals representative of intervals between depolarization events and ends of corresponding repolarization events within electrical cardiac signals and to track elevations of segments of the cardiac signals between depolarization events and corresponding repolarization events; and a hyperglycemia detection unit operative to detect an episode of hyperglycemia based on changes or lack of changes in the elevations of the segments, the repolarization peak-based intervals, and the repolarization end-based intervals.
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13. A system for use with an implantable medical device for detecting hyperglycemia in a patient in which the device is implanted comprising:
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means for tracking repolarization peak-based intervals between depolarization events and peaks of corresponding repolarization events within electrical cardiac signals; means for tracking repolarization end-based intervals between depolarization events and ends of corresponding repolarization events within electrical cardiac signals; means for tracking elevations of segments of the cardiac signals between ends of depolarization events and corresponding repolarization events; and means for detecting an episode of hyperglycemia based on changes, if any, in the elevations of the segments, the repolarization peak-based intervals, and the repolarization end-based intervals.
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14. A method for use with an implantable medical device for distinguishing among hypoglycemia, hyperglycemia and cardiac ischemia within a patient in which the device is implanted comprising the steps of:
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tracking repolarization-based intervals between depolarization events and corresponding repolarization events within electrical cardiac signals; and tracking elevations of segments of the cardiac signals between ends of depolarization events and corresponding repolarization events; and distinguishing among hypoglycemia, hyperglycemia and cardiac ischemia based on changes, if any, in the elevations of the segments in combination with changes, if any, in the repolarization-based intervals.
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Specification