System and method for adaptively adjusting cardiac ischemia detection thresholds and other detection thresholds used by an implantable medical device
First Claim
1. A method for use with an implantable medical device having a detection system that detects an abnormal physiological condition within a patient in which the device is implanted by comparing at least one morphological parameter against a detection threshold, wherein the morphological parameter is derived from signals sensed within the patient, the method comprising:
- sensing signals within the patient and deriving values of the morphological parameter from the signals;
monitoring the values of the morphological parameter to detect a possible occurrence of the abnormal physiological condition;
collecting information representative of a range of variation in the morphological parameter within the patient;
adjusting the detection threshold based on the information representative of the range of variation in the morphological parameter collected within the patient to improve detection accuracy; and
wherein collecting information representative of a range of variation in the morphological parameter within the patient includes;
selectively incrementing a plurality of counters based on the plurality of measurements, wherein the counters are representative of different ranges of measurements.
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Accused Products
Abstract
Techniques are described for adaptively adjusting detection thresholds for use in detecting cardiac ischemia and other abnormal physiological conditions based on morphological parameters derived from intracardiac electrogram (IEGM) signals, impedance measurements, or other signals. In one example, where ST segment elevation is used to detect cardiac ischemia, default detection thresholds are determined in advance from an examination of variations in ST segment elevations occurring within a population of patients. Thereafter, an individual pacemaker or other implantable medical device uses the default thresholds during an initial learning period to detect ischemia within the patient in which the device is implanted. During the initial learning period, the pacemaker also collects data representative of the range of variation in ST segment elevations occurring within the patient. The pacemaker then adaptively adjusts the thresholds based on the range of variation so as to improve detection specificity within the patient.
69 Citations
11 Claims
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1. A method for use with an implantable medical device having a detection system that detects an abnormal physiological condition within a patient in which the device is implanted by comparing at least one morphological parameter against a detection threshold, wherein the morphological parameter is derived from signals sensed within the patient, the method comprising:
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sensing signals within the patient and deriving values of the morphological parameter from the signals; monitoring the values of the morphological parameter to detect a possible occurrence of the abnormal physiological condition; collecting information representative of a range of variation in the morphological parameter within the patient; adjusting the detection threshold based on the information representative of the range of variation in the morphological parameter collected within the patient to improve detection accuracy; and wherein collecting information representative of a range of variation in the morphological parameter within the patient includes; selectively incrementing a plurality of counters based on the plurality of measurements, wherein the counters are representative of different ranges of measurements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for use with an implantable medical device having a detection system that detects an abnormal physiological condition within a patient in which the device is implanted by comparing at least one morphological parameter against a detection threshold, wherein the morphological parameter is derived from signals sensed within the patient, the method comprising:
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sensing signals within the patient and deriving values of the morphological parameter from the signals; monitoring the values of the morphological parameter to detect a possible occurrence of the abnormal physiological condition; collecting information representative of a range of variation in the morphological parameter within the patient; adjusting the detection threshold based on the information representative of the range of variation in the morphological parameter collected within the patient to improve detection accuracy; and wherein adjusting the threshold based on the information collected within the patient is performed to achieve a target percentile value within a range of variation in the morphological parameter observed within the patient.
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10. A method for use with an implantable medical device having a detection system that detects an abnormal physiological condition within a patient in which the device is implanted by comparing at least one morphological parameter against a detection threshold, wherein the morphological parameter is derived from signals sensed within the patient, the method comprising:
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sensing signals within the patient and deriving values of the morphological parameter from the signals; monitoring the values of the morphological parameter to detect a possible occurrence of the abnormal physiological condition; collecting information representative of a range of variation in the morphological parameter within the patient; adjusting the detection threshold based on the information representative of the range of variation in the morphological parameter collected within the patient to improve detection accuracy; wherein a plurality of detection thresholds are specified for use under different conditions, and wherein the plurality of detection thresholds are independently set and adjusted based on the range of variation of the morphological parameter during the different conditions.
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11. A method for use with an implantable medical device having a detection system that detects an abnormal physiological condition within a patient in which the device is implanted by comparing at least one morphological parameter against a detection threshold, wherein the morphological parameter is derived from signals sensed within the patient, the method comprising:
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sensing signals within the patient and deriving values of the morphological parameter from the signals; monitoring the values of the morphological parameter to detect a possible occurrence of the abnormal physiological condition; collecting information representative of a range of variation in the morphological parameter within the patient; adjusting the detection threshold based on the information representative of the range of variation in the morphological parameter collected within the patient to improve detection accuracy; and wherein the detection thresholds include persistence-based thresholds.
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Specification