Method and system for extracting cardiac parameters from plethysmographic signals
First Claim
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10. A method for extracting a cardiac component from a plethysmographic signal, the plethysmographic signal being responsive to cardiac motion, the method comprising the steps of:
- performing a frequency domain filtering operation on the plethysmographic signal producing a filtered signal, wherein the frequency domain filtering operation comprises applying a band-pass filter having a lower corner frequency that varies in dependence on current heart rate; and
outputting the filtered signal.
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Abstract
A method and system for extracting cardiac parameters from a plethysmographic signal is described wherein the plethysmographic signal is passed through a first filter to remove non-cardiac components of the signal. A second filter averages a plurality of cardiac cycles and cardiac parameters are extracted from the averaged cardiac signal.
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Citations
19 Claims
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10. A method for extracting a cardiac component from a plethysmographic signal, the plethysmographic signal being responsive to cardiac motion, the method comprising the steps of:
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performing a frequency domain filtering operation on the plethysmographic signal producing a filtered signal, wherein the frequency domain filtering operation comprises applying a band-pass filter having a lower corner frequency that varies in dependence on current heart rate; and
outputting the filtered signal. - View Dependent Claims (11, 12)
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13. A system for extracting a cardiac component from a plethysmographic signal, the plethysmographic signal being responsive to cardiac motion, the system comprising a processor coupled to a memory, wherein the memory includes stored instructions for causing the processor to
perform a frequency domain filtering operation on the plethysmographic signal producing a filtered signal, wherein the frequency domain filtering operation comprises applying a band-pass filter having a lower corner frequency that varies in dependence on current heart rate; - and
output the filtered signal. - View Dependent Claims (14, 15)
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16-1. The system of claim 16 wherein the processor further extracts from the output signal one or more cardiac parameters selected from the group consisting of stroke volume, cardiac output, pre-ejection period, peak ejection rate, and time to peak ejection rate.
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