IMPLANTABLE TISSUE PERFUSION SENSING SYSTEM AND METHOD
First Claim
1. A medical device for sensing cardiac events, comprising:
- a plurality of light sources capable of emitting light at a plurality of wavelengths;
a detector to detect the emitted light; and
a processor to determine a plurality of light measurements in response to the emitted light detected by the detector, to update, for each of the plurality of wavelengths, a first normalization coefficient and a second normalization coefficient in response to the detected emitted light, and to adjust the determined plurality of light measurements in response to the first normalization coefficient and the second normalization coefficient,wherein the first normalization coefficient corresponds to peak-to-peak changes in the plurality of light measurements and the second normalization coefficient corresponds to average amplitudes of the plurality of light measurements,wherein the processor determines a first baseline associated with the first normalization coefficient and a second baseline associated with the second normalization coefficient, andwherein the first normalization coefficient is updated in response to a ratio of the first baseline and an average of the peak-to-peak changes in the plurality of light measurements, and the second normalization coefficient is updated in response to a difference between a product of the previously updated first normalization coefficient and a current average amplitude and the second baseline.
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Abstract
A medical device for sensing cardiac events that includes 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, updates, for each of the plurality of wavelengths, a first normalization coefficient and a second normalization coefficient in response to the detected emitted light, and adjusts the determined plurality of light measurements in response to the first normalization coefficient and the second normalization coefficient.
26 Citations
8 Claims
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1. A medical device for sensing cardiac events, comprising:
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a plurality of light sources capable of emitting light at a plurality of wavelengths; a detector to detect the emitted light; and a processor to determine a plurality of light measurements in response to the emitted light detected by the detector, to update, for each of the plurality of wavelengths, a first normalization coefficient and a second normalization coefficient in response to the detected emitted light, and to adjust the determined plurality of light measurements in response to the first normalization coefficient and the second normalization coefficient, wherein the first normalization coefficient corresponds to peak-to-peak changes in the plurality of light measurements and the second normalization coefficient corresponds to average amplitudes of the plurality of light measurements, wherein the processor determines a first baseline associated with the first normalization coefficient and a second baseline associated with the second normalization coefficient, and wherein the first normalization coefficient is updated in response to a ratio of the first baseline and an average of the peak-to-peak changes in the plurality of light measurements, and the second normalization coefficient is updated in response to a difference between a product of the previously updated first normalization coefficient and a current average amplitude and the second baseline. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification