Implantable tissue perfusion sensing system and method
First Claim
1. A medical device for sensing cardiac events, comprising:
- a plurality of electrodes sensing cardiac signals utilized to identify a cardiac event;
a plurality of light sources capable of emitting light at a plurality of wavelengths;
a detector to detect the emitted light; and
a processor configured to determine a plurality of light measurements in response to the emitted light detected by the detector, to determine an isobestic blood volume index in response to determined light measurements of the plurality of light measurements from a first light source of the plurality of light sources emitting light at an isobestic wavelength, to determine an oxygen index in response to a difference between a light measurement of the plurality of light measurements from a light source of the plurality of light sources emitting light at a non-isobestic wavelength and a product of the determined isobestic blood volume index and a correction factor determined for the non-isobestic wavelength, and to verify the identifying of the cardiac event in response to the determined isobestic blood volume index and the determined oxygen index.
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Accused Products
Abstract
A medical device for sensing cardiac events that includes a plurality of electrodes sensing cardiac signals utilized to identify a cardiac event, a plurality of light sources capable of emitting light at a plurality of wavelengths, and a detector to detect the emitted light. A processor determines a plurality of light measurements in response to the emitted light detected by the detector, an isobestic blood volume index in response to determined light measurements of the plurality of light measurements from a first light source of the plurality of light sources emitting light at an isobestic wavelength, determines an oxygen index associated with light measurements of the plurality of light measurements from a light source of the plurality of light sources other than the first light source, and verifies the identifying of the cardiac event in response to the determined isobestic blood volume index and the determined oxygen index.
54 Citations
20 Claims
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1. A medical device for sensing cardiac events, comprising:
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a plurality of electrodes sensing cardiac signals utilized to identify a cardiac event; a plurality of light sources capable of emitting light at a plurality of wavelengths; a detector to detect the emitted light; and a processor configured to determine a plurality of light measurements in response to the emitted light detected by the detector, to determine an isobestic blood volume index in response to determined light measurements of the plurality of light measurements from a first light source of the plurality of light sources emitting light at an isobestic wavelength, to determine an oxygen index in response to a difference between a light measurement of the plurality of light measurements from a light source of the plurality of light sources emitting light at a non-isobestic wavelength and a product of the determined isobestic blood volume index and a correction factor determined for the non-isobestic wavelength, and to verify the identifying of the cardiac event in response to the determined isobestic blood volume index and the determined oxygen index. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A medical device for sensing cardiac events, comprising:
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a plurality of electrodes sensing cardiac signals utilized to identify a cardiac event; a plurality of light sources capable of emitting light at a plurality of wavelengths; a detector to detect the emitted light; and a processor configured to determine a plurality of light measurements in response to the emitted light detected by the detector, to determine an isobestic blood volume index in response to determined light measurements of the plurality of light measurements from a first light source of the plurality of light sources emitting light at an isobestic wavelength, to determine a first oxygen index in response to differences between a light measurement of the plurality of light measurements from a second light source and a third light source of the plurality of light sources emitting light at a non-isobestic wavelength and a product of the determined isobestic blood volue index and a correction factor determined for the non-isobestic wavelength of the second light source, to determine a second oxygen index in response to differences between a light measurement of the plurality of light measurements from a third light source of the plurality of light sources emitting light at a non-isobestic wavelength and a product of the determined isobestic blood volume index and a correction factor determined for the non-isobestic wavelength of the third light source, and to verify the identifying of the cardiac event in response to the determined isobestic blood volume index and a ratio-metric combination of the first oxygen index and the second oxygen index. - View Dependent Claims (10, 11, 12)
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13. A method for verifying sensing of a cardiac event by a medical device, comprising:
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identifying the cardiac event in response to sensed cardiac signals; determining light emitted by a plurality of light sources at a plurality of wavelengths; determining a plurality of light measurements in response to the detected emitted light; determining an isobestic blood volume index in response to determined light measurements of the plurality of light measurements from a first light source of the plurality of light sources emitting light at an isobestic wavelength; determining an oxygen index in response to a difference between a light measurement of the plurality of light measurements from a light source of the plurality of light sources emitting light at a non-isobestic wavelength and a product of the determined isobestic blood volume index and a correction factor determined for the non-isobestic wavelength; and verifying the identifying of the cardiac event in response to the determined isobestic blood volume index and the determined oxygen index. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification