System and method for infrasonic cardiac monitoring
First Claim
1. A method for computing cardiac stroke volume of a subject, comprising:
- obtaining parameters of a wavelet packet function and basing the parameters on calibration data from a plurality of members of a population, the wavelet packet function relating information from a transducer representing chest wall movements associated with a respective heartbeat to cardiac stroke volume of the respective heartbeat;
measuring chest wall movements of the subject;
performing a wavelet transform on the measured chest wall movements of the subject to produce a set of wavelet transformed data;
determining, from the wavelet transformed data and the parameters of the wavelet packet function, at least a cardiac stroke volume of the respective heartbeat for the subject; and
one of (a) displaying on a display device, and (b) controlling a therapeutic cardiac device, based on at least one of (i) the determined cardiac stroke volume, and (ii) a value calculated from the determined cardiac stroke volume.
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Accused Products
Abstract
Cardiac Output (CO) has traditionally been difficult, dangerous, and expensive to obtain. Surrogate measures such as pulse rate and blood pressure have therefore been used to permit an estimate of CO. MEMS technology, evolutionary computation, and time-frequency signal analysis techniques provide a technology to non-invasively estimate CO, based on precordial (chest wall) motions. The technology detects a ventricular contraction time point, and stroke volume, from chest wall motion measurements. As CO is the product of heart rate and stroke volume, these algorithms permit continuous, beat to beat CO assessment. Nontraditional Wavelet analysis can be used to extract features from chest acceleration. A learning tool is preferable to define the packets which best correlate to contraction time and stroke volume.
1936 Citations
25 Claims
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1. A method for computing cardiac stroke volume of a subject, comprising:
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obtaining parameters of a wavelet packet function and basing the parameters on calibration data from a plurality of members of a population, the wavelet packet function relating information from a transducer representing chest wall movements associated with a respective heartbeat to cardiac stroke volume of the respective heartbeat; measuring chest wall movements of the subject; performing a wavelet transform on the measured chest wall movements of the subject to produce a set of wavelet transformed data; determining, from the wavelet transformed data and the parameters of the wavelet packet function, at least a cardiac stroke volume of the respective heartbeat for the subject; and one of (a) displaying on a display device, and (b) controlling a therapeutic cardiac device, based on at least one of (i) the determined cardiac stroke volume, and (ii) a value calculated from the determined cardiac stroke volume.
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2. A system for computing a cardiac performance, comprising:
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a display device configured to present a display; a transducer configured to sense chest wall movements of a subject and to produce a transducer output representing the sensed chest wall movements; a memory storing parameters of a wavelet packet function, the stored parameters being based on calibration data from a plurality of members of a population, the wavelet packet function relating sensed chest wall movements associated with a respective heartbeat to cardiac stroke volume of the respective heartbeat at least one automated processor, configured to; retrieve, from the memory, stored parameters of the wavelet packet function; perform a wavelet transform on the sensed chest wall movements; and calculate at least a cardiac stroke volume estimate of the respective heartbeat from the wavelet transformed sensed chest wall movements and the parameters, using the retrieved parameters for the wavelet packet function; and one of;
(a) display information selectively dependent on the cardiac stroke volume estimate to the display device, for presentation to a user, and (b) control a therapeutic cardiac medical device selectively dependent on the cardiac stroke volume estimate. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A system for computing cardiac performance, comprising:
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a memory configured to store parameters of a wavelet packet function, the stored parameters being based on calibration data from a plurality of members of a human population relating chest wall movement data to at least cardiac stroke volume; a transducer configured to sense chest wall movement data from a respective human; a wavelet transform processor, configured to produce a wavelet transform of the chest wall movement data of the respective human; a cardiac stroke volume processor, configured to evaluate the wavelet packet function to at least estimate a cardiac stroke volume of the respective human based on the wavelet transform of the chest wall movement data and the stored parameters of the wavelet packet function; and one of; (a) a display device configured to display the estimated cardiac stroke volume; and (b) a therapeutic cardiac device configured to deliver a therapy to the respective human selectively dependent on the estimated cardiac stroke volume.
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Specification