Ischemia detection based on cardiac conduction time
First Claim
1. A method comprising:
- detecting ST segment deviations via a wholly-implantable medical device (IMD);
detecting patient activity levels via the IMD;
detecting cardiac conduction time between at least a first pair and a second pair of fully implantable fixed electrodes which are all operatively coupled to an active implantable medical device (IMD), wherein said first pair and said second pair are separate pairs of fully-implantable electrodes; and
indicating myocardial ischemia based on each one of;
(i) changes in conduction time in combination with ST segment deviation, (ii) changes in conduction time in combination with a detected patient activity level, and (iii) the time rate of change of conduction time wherein conduction time is detected between said first pair and said second pair of fully implantable electrodes.
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Accused Products
Abstract
Methods and process for detection of myocardial ischemia involve detection and analysis of changes in electrical conduction velocity within the heart to monitor changes in the condition of the cardiac muscle and indicate possible ischemia. Conduction velocity slows considerably when oxygen supply to the heart is reduced. Analysis of electrical conduction velocity can be used to verify the occurrence of myocardial ischemia in a more reliable manner. Changes in conduction velocity may be monitored based on conduction time between electrodes positioned in the left and right ventricles of the heart. The electrodes may be endocardial or epicardial electrodes. In general, the techniques may involve launching a stimulation waveform at one electrode and sensing a local cardiac depolarization at another electrode to assess conduction time.
61 Citations
33 Claims
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1. A method comprising:
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detecting ST segment deviations via a wholly-implantable medical device (IMD); detecting patient activity levels via the IMD; detecting cardiac conduction time between at least a first pair and a second pair of fully implantable fixed electrodes which are all operatively coupled to an active implantable medical device (IMD), wherein said first pair and said second pair are separate pairs of fully-implantable electrodes; and indicating myocardial ischemia based on each one of;
(i) changes in conduction time in combination with ST segment deviation, (ii) changes in conduction time in combination with a detected patient activity level, and (iii) the time rate of change of conduction time wherein conduction time is detected between said first pair and said second pair of fully implantable electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A device comprising:
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a wholly-implantable medical device (IMD) including a detector to detect cardiac conduction time between a first pair and a second pair of fully implantable electrodes and a second pair of fully implantable electrodes, and indicate myocardial ischemia based on the detected conduction time of at least one of said first pair and second pair of fully implantable electrodes, wherein said detector includes; means for comparing the detected conduction time of said first pair and said second pair to a respective threshold conduction time for said first pair and said second pair; means for detecting ST segment deviation disposed within the IMD; means for detecting patient activity level disposed within the IMD; and means for indicating ischemia, also disposed within the IMD, based on each one of the following;
(i) changes in conduction time in combination with ST segment deviation, (ii) changes in conduction time in combination with a detected patient activity level, and (iii) the time rate of change of conduction time wherein conduction time is the detected conduction time between said first pair and said second pair of fully implantable electrodes. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A device comprising:
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means for detecting cardiac conduction time between a first pair of fully implantable electrodes and between a second pair of fully implantable electrodes; means for detecting ST segment deviation disposed within a wholly-implantable medical device (IMD); means for detecting patient activity level disposed within the IMD; and means for indicating myocardial ischemia, also disposed within the IMD, based on the detected conduction time of at least one of said first pair and said second pair of electrodes, wherein the means for indicating myocardial ischemia is based upon each one of;
(i) changes in conduction time in combination with ST segment deviation, (ii) changes in conduction time in combination with the detected patient activity level, (iii) the time rate of change of conduction time, and (iv) an average conduction time measurement derived from multiple conduction time measurements wherein conduction time is the detected conduction time between said first pair and said second pair of fully implantable electrodes. - View Dependent Claims (20, 21, 22, 23, 24)
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25. An apparatus, comprising:
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means for detecting cardiac conduction time between at least a first pair and a second pair of fully implantable electrodes coupled to an active wholly-implantable medical device (IMD); means for detecting ST segment deviation disposed within the IMD; means for detecting patient activity level disposed within the IMD; and means for indicating myocardial ischemia, also disposed within the IMD, based on each one of;
(i) changes in conduction time in combination with ST segment deviation, (ii) changes in conduction time in combination with the detected patient activity level, and (iii) the time rate of change of conduction time, and wherein conduction time is the detected conduction time between said first pair and said second pair of fully implantable electrodes. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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Specification