Use of motion sensor for dynamic updating of heart detection threshold
First Claim
1. A method for detecting a heart rate of a patient, comprising the steps of:
- (a) sensing via a first sensor a first signal indicative of heart rate;
(b) sensing via a second sensor a second signal indicative of motion of the patient'"'"'s chest due to respiration;
(c) adjusting a threshold value of the amplitude of the first signal based on the second signal; and
(d) determining the heart rate as a function of the adjusted threshold value and the first signal,wherein step (c) comprises;
increasing the threshold value in response to a determination of inflation of a patient'"'"'s chest due to respiration,decreasing the threshold value in response to a determination of deflation of the patient'"'"'s chest due to respiration, andkeeping the threshold value constant in response to a determination of no substantial movement of the patient'"'"'s chest.
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Accused Products
Abstract
A method for accurate heart rate detection includes receiving a signal indicative of motion due to respiration, and using the signal indicative of motion to adjust a threshold value of a signal indicative of activity of the heart. The adjusted threshold value is used to detect an accurate heart rate of a patient. A system for accurate heart rate detection comprises a motion sensor which produces a signal indicative of motion due to respiration, and a processor which adjusts a threshold value of a signal indicative of activity of the heart according to the signal indicative of motion. The adjusted threshold value is used to detect an accurate heart rate of a patient. The motion sensor can be any device that can determine direction of motion, such as an accelerometer, a displacement sensor, a velocity sensor, or a photoplethysmography (PPG) sensor.
62 Citations
28 Claims
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1. A method for detecting a heart rate of a patient, comprising the steps of:
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(a) sensing via a first sensor a first signal indicative of heart rate; (b) sensing via a second sensor a second signal indicative of motion of the patient'"'"'s chest due to respiration; (c) adjusting a threshold value of the amplitude of the first signal based on the second signal; and (d) determining the heart rate as a function of the adjusted threshold value and the first signal, wherein step (c) comprises; increasing the threshold value in response to a determination of inflation of a patient'"'"'s chest due to respiration, decreasing the threshold value in response to a determination of deflation of the patient'"'"'s chest due to respiration, and keeping the threshold value constant in response to a determination of no substantial movement of the patient'"'"'s chest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for detecting a heart rate of a patient, comprising:
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first sensing means for sensing a first signal indicative of heart rate; second sensing means for sensing a second signal indicative of motion of the patient'"'"'s chest due to respiration; means for adjusting a threshold value of the amplitude of the first signal based on the second signal; and means for determining the heart rate as a function of the adjusted threshold value and the first signal, wherein the means for adjusting a threshold value is configured to increase the threshold value in response to a determination of inflation of the patient'"'"'s chest due to respiration, decrease the threshold value in response to a determination of deflation of the patient'"'"'s chest due to respiration, and to not change the threshold value in response to a determination of no substantial movement of the patient'"'"'s chest. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. An implantable cardiac device, comprising:
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a physiologic sensor configured to produce a first signal indicative of heart rate; a motion sensor independent of the physiologic sensor and configured to produce a second signal indicative of motion of a patient'"'"'s chest due to respiration; and a processor configured to; adjust a threshold value of the amplitude of the first signal based on the second signal; and determine the heart rate as a function of the adjusted threshold value and the first signal, wherein the processor is configured to increase the threshold value upon a determination of an inflation of a subject'"'"'s chest due to respiration, the processor is configured to decrease the threshold value upon a determination of a deflation of the subject'"'"'s chest due to respiration, and the processor is configured to maintain the threshold value as substantially constant upon a determination of no substantial movement of the subject'"'"'s chest. - View Dependent Claims (20, 21)
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22. A method for detecting a heart rate of a patient, comprising:
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(a) sensing a first signal indicative of a heart rate of a patient'"'"'s heart; (b) sensing a second signal indicative of motion due to the patient'"'"'s respiration, wherein the second signal is sensed independently of the first signal; (c) as a function of the second signal, adjusting an amplitude threshold value associated with the first signal, said adjusted amplitude threshold value being indicative of an amplitude value that the first signal usually exceeds only during a contraction of the patient'"'"'s heart; and (d) detecting the heart rate based on a comparison of the first signal with the adjusted amplitude threshold value, wherein step (c) comprises; increasing the amplitude threshold value in response to a determination of inflation of a patient'"'"'s chest due to respiration, decreasing the amplitude threshold value in response to a determination of deflation of the patient'"'"'s chest due to respiration, and keeping the amplitude threshold value constant in response to a determination of no substantial movement of the patient'"'"'s chest. - View Dependent Claims (23)
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24. A system for detecting a heart rate of a patient, comprising:
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first means for sensing a first signal indicative of a heart rate of a patient'"'"'s heart; second means for sensing a second signal indicative of motion due to the patient'"'"'s respiration, wherein the second means is independent of the first means and the second signal is thereby independent of the first signal; means for adjusting an amplitude threshold value associated with the first signal and configured to adjust said amplitude threshold value as a function of the second signal, wherein said adjusted amplitude threshold value is indicative of an amplitude value that the first signal usually exceeds only during a contraction of the patient'"'"'s heart; and means for detecting the heart rate based on a comparison of the first signal with the adjusted amplitude threshold value, wherein the means for adjusting an amplitude threshold value is configured to increase the amplitude threshold value in response to a determination of inflation of the patient'"'"'s chest due to respiration, decrease the amplitude threshold value in response to a determination of deflation of the patient'"'"'s chest due to respiration, and to not change the amplitude threshold value in response to a determination of no substantial movement of the patient'"'"'s chest. - View Dependent Claims (25)
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26. An implantable cardiac device (ICD), comprising:
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a physiologic sensor configured to produce a first signal indicative of a heart rate of a patient'"'"'s heart; a motion sensor independent of the physiologic sensor and configured to produce a second signal indicative of motion due to the patient'"'"'s respiration, whereby the second signal is independent of the first signal; and a processor configured to; adjust an amplitude threshold value associated with the first signal, said adjustment being a function of the second signal; adjust said amplitude threshold value such that said adjusted threshold value is indicative of an amplitude value that the first signal usually exceeds only during a contraction of the patient'"'"'s heart; and detect the heart rate based on a comparison of the first signal with the adjusted amplitude threshold value. - View Dependent Claims (27, 28)
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Specification