Cardiac stimulation device for optimizing cardiac output with myocardial ischemia protection
First Claim
1. In a cardiac stimulation device, a method of monitoring myocardial ischemia comprising:
- determining a sensor indicated heart rate;
pacing at the sensor indicated heart rate;
sensing an intracardiac electrogram signal;
detecting myocardial ischemia based on a change in the electrogram signal; and
in response to detecting myocardial ischemia, ignoring the sensor indicated rate and selectively adjusting one or more pacing parameters;
wherein selectively adjusting one or more pacing parameters comprises varying an inter-ventricular timing interval.
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Abstract
A cardiac stimulation device and method detect myocardial ischemia and provide a response for alleviating the ischemia. Myocardial ischemia is detected by identifying changes in the ST-segment of the intracardiac electrogram (EGM) sensed using large sensing electrode surfaces created by electrically coupling one or more cardiac electrodes or by using larger surface area shocking coils. Myocardial ischemia monitoring is performed when stimulation parameters are adjusted for increasing cardiac output, causing an increased metabolic demand to be placed on the myocardium itself. When myocardial ischemia is detected, stimulation parameters are re-adjusted to reduce the demand placed on the myocardium and thereby alleviate the ischemia.
204 Citations
72 Claims
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1. In a cardiac stimulation device, a method of monitoring myocardial ischemia comprising:
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determining a sensor indicated heart rate;
pacing at the sensor indicated heart rate;
sensing an intracardiac electrogram signal;
detecting myocardial ischemia based on a change in the electrogram signal; and
in response to detecting myocardial ischemia, ignoring the sensor indicated rate and selectively adjusting one or more pacing parameters;
wherein selectively adjusting one or more pacing parameters comprises varying an inter-ventricular timing interval.
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2. In a cardiac stimulation device, a method of monitoring myocardial ischemia comprising:
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determining a sensor indicated heart rate;
pacing at the sensor indicated heart rate;
sensing an intracardiac electrogram signal;
detecting myocardial ischemia based on a chance in the electrogram signal; and
in response to detecting myocardial ischemia, ignoring the sensor indicated rate and selectively adjusting one or more pacing parameters;
wherein selectively adjusting one or more pacing parameters comprises varying an inter-atrial timing interval.
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3. In a cardiac stimulation device, a method of monitoring myocardial ischemia comprising:
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determining a sensor indicated heart rate;
pacing at the sensor indicated heart rate;
sensing an intracardiac electrogram signal;
detecting myocardial ischemia based on a chance in the electrogram signal;
in response to detecting myocardial ischemia, ignoring the sensor indicated rate and selectively adjusting one or more pacing parameters; and
switching from a single-chamber ventricular stimulation mode to a biventricular stimulation mode;
wherein detecting myocardial ischemia comprises detecting a deviation of an ST-segment of the cardiac electrogram signal; and
wherein detecting the deviation of the ST-segment comprises detecting any of;
an elevation of the ST-segment relative to a PQ-segment;
an elevation of the ST-segment relative to a TP-segment;
a depression of the ST-segment relative to a PQ-segment;
a depression of the ST-segment relative to a TP-segment; and
an inversion of a T-wave.
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4. In a cardiac stimulation device, a method of monitoring myocardial ischemia comprising:
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determining a sensor indicated heart rate;
pacing at the sensor indicated heart rate;
sensing an intracardiac electrogram signal;
detecting myocardial ischemia based on a change in the electrogram signal; and
in response to detecting myocardial ischemia, ignoring the sensor indicated rate and selectively adjusting one or more pacing parameters;
wherein sensing the cardiac electrogram signal comprises electrically coupling at least two sensing electrodes to form a single sensing electrode with an expanded surface. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. In a cardiac stimulation device, a method of monitoring myocardial ischemia comprising:
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electrically coupling at least two sensing electrodes to form a single sensing electrode with an expanded surface;
sensing an intracardiac electrogram signal using the single sensing electrode; and
detecting myocardial ischemia based on a change in the electrogram signal. - View Dependent Claims (21, 22, 23, 24, 25)
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26. A cardiac stimulation device that monitors myocardial ischemia, comprising:
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an electrode having at least two sensing electrodes, the at least two sensing electrodes electrically coupled to form a single sensing electrode with an expanded surface;
a sensing circuit coupled to the electrode to sense an intracardiac electrogram signal;
a control circuit that determines a sensor indicated heart rate;
a pulse generator that generates stimulation pulses at the sensor indicated heart rate;
an ischemia detector, connected to the ischemia sensing circuit, that detects myocardial ischemia based on a change in the electrogram signal; and
wherein the control circuit is responsive to detection of myocardial ischemia to ignore the sensor indicated rate and to selectively adjust one or more pacing parameters. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A cardiac stimulation device that monitors myocardial ischemia, comprising:
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circuitry that is operative to electrically couple at least two sensing electrodes to form a single sensing electrode with an expanded surface;
an ischemia sensing circuit that senses a cardiac electrogram signal, using the coupled electrodes; and
an ischemia detector, connected to the ischemia sensing circuit, that detects myocardial ischemia based on a change in the electrogram signal. - View Dependent Claims (40, 41, 42)
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43. A cardiac stimulation device that monitors myocardial ischemia, comprising:
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means for determining a sensor indicated heart rate;
means for pacing at the sensor indicated heart rate;
means for coupling at least two sensing electrodes to form a single sensing electrode with an expanded surface;
means for sensing an intracardiac electrogram signal;
means for detecting myocardial ischemia based on a change in the electrogram signal; and
wherein in response to detected myocardial ischemia the pacing means comprises means for ignoring the sensor indicated rate and for adjusting one or more pacing parameters. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52)
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53. A cardiac stimulation device that monitors myocardial ischemia, comprising:
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means for electrically coupling at least two sensing electrodes to form a single sensing electrode with an expanded surface;
means for sensing a cardiac electrogram signal, using the coupled electrodes; and
means for detecting myocardial ischemia based on a change in the electrogram signal. - View Dependent Claims (54, 55, 56)
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57. In a cardiac stimulation device, a method of monitoring myocardial ischemia comprising:
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implementing a pacing scheme;
sensing an intracardiac electrogram signal;
detecting myocardial ischemia based on a change in the electrogram signal; and
in response to detecting myocardial ischemia, varying an inter-chamber timing interval in the pacing scheme. - View Dependent Claims (58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72)
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Specification