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 hypoglycemia in a patient in which the device is implanted, the method comprising:
- tracking QTmax intervals representative of intervals between QRS-complexes and peaks of corresponding T-waves within electrical cardiac signals; and
detecting an episode of hypoglycemia based on a lengthening of the QTmax 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
18 Claims
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1. A method for use with an implantable medical device for detecting hypoglycemia in a patient in which the device is implanted, the method comprising:
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tracking QTmax intervals representative of intervals between QRS-complexes and peaks of corresponding T-waves within electrical cardiac signals; and detecting an episode of hypoglycemia based on a lengthening of the QTmax intervals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for use with an implantable medical device for detecting hypoglycemia in a patient in which the device is implanted comprising:
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a timing unit configured to track QTmax intervals representative of intervals between QRS-complexes and peaks of corresponding T-waves within electrical cardiac signals; and a hypoglycemia detection unit configured to detect an episode of hypoglycemia based on a significant increase in the duration of the QTmax intervals.
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16. A system for use with an implantable medical device for detecting hypoglycemia in a patient in which the device is implanted comprising:
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a timing unit configured to track QTmax values representative of intervals between QRS-complexes and peaks of corresponding T-waves within electrical cardiac signals, to track QTend values representative of intervals between the QRS-complexes and ends of corresponding T-waves, and to track ST segment elevation representative of elevations of segments of the cardiac signals between S-waves and corresponding T-waves; and a hypoglycemia detection unit configured to detect an episode of hypoglycemia based on a change in ST segment elevation combined with an increase in both QTend and QTmax intervals.
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17. A system for use with an implantable medical device for detecting hypoglycemia in a patient in which the device is implanted comprising:
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means for tracking QTmax intervals representative of intervals between QRS-complexes and peaks of corresponding T-waves within electrical cardiac signals; and means for detecting an episode of hypoglycemia based on a lengthening of the QTmax intervals.
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18. A method for use with an implantable medical device for detecting hypoglycemia in a patient in which the device is implanted, the method comprising:
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tracking QTmax values representative of intervals between QRS-complexes and peaks of corresponding T-waves within electrical cardiac signals, tracking QTend values representative of intervals between the QRS-complexes and ends of corresponding T-waves, tracking ST segment elevation representative of elevations of segments of the cardiac signals between S-waves and corresponding T-waves; and detecting an episode of hypoglycemia based on a change in ST segment elevation combined with an increase in both QTend and QTmax intervals.
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Specification