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 cardiac ischemia 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; and
detecting an episode of cardiac ischemia based on a decrease in the repolarization peak-based intervals.
1 Assignment
0 Petitions
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.
132 Citations
24 Claims
-
1. A method for use with an implantable medical device for detecting cardiac ischemia 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; and
detecting an episode of cardiac ischemia based on a decrease in the repolarization peak-based intervals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. A system for use with an implantable medical device for detecting cardiac ischemia in a patient in which the device is implanted comprising:
-
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; and
a cardiac ischemia detection unit operative to detect an episode of cardiac ischemia based on a decrease in the repolarization peak-based intervals.
-
-
18. A system for use with an implantable medical device for detecting cardiac ischemia in a patient in which the device is implanted comprising:
-
a timing unit operative to track QTmax values representative of intervals between QRS complexes and peaks of corresponding T-waves within electrical cardiac signals;
a cardiac ischemia detection unit operative to detect an episode of cardiac ischemia based on a decrease in the QTmax intervals;
a warning system operative to warn the patient in response to detection of ischemia; and
a therapy control unit operative to control therapy delivered to the patient in response to detection of ischemia
-
-
19. A system for use with an implantable medical device for detecting cardiac ischemia in a patient in which the device is implanted comprising:
-
means for tracking repolarization peak-based intervals representative of intervals between depolarization events and peaks of corresponding repolarization events within electrical cardiac signals; and
means for detecting an episode of cardiac ischemia based on a decrease in the repolarization peak-based intervals.
-
-
20. A method for use with an implantable medical device for detecting cardiac ischemia in a patient in which the device is implanted comprising:
-
tracking elevations of segments of cardiac signals between depolarization events and corresponding repolarization events within electrical cardiac signals;
detecting a possible ischemia based on a change in elevation of the ST segments;
tracking repolarization-based intervals representative of intervals between depolarization events and corresponding repolarization events within the electrical cardiac signals; and
verifying the detection of ischemia based on an examination of the repolarization-based intervals.
-
-
21. A method for use with an implantable medical device for detecting ischemia within a patient in which the device is implanted comprising the steps of:
-
tracking activation/deactivation-based intervals between electrical cardiac signals representative of electrical activation of the ventricles and electrical cardiac signals representative of corresponding deactivation of the ventricles; and
detecting ischemia based on an examination of the activation/deactivation-based intervals. - View Dependent Claims (22)
-
-
23. A method for use with an implantable medical device for distinguishing among medical conditions within a patient in which the device is implanted comprising the steps of:
-
tracking activation/deactivation-based intervals between electrical cardiac signals representative of electrical activation of the ventricles and electrical cardiac signals representative of corresponding deactivation of the ventricles; and
distinguishing among ischemia, hypoglycemia and hyperglycemia based on an examination of the activation/deactivation-based intervals. - View Dependent Claims (24)
-
Specification