System and method for facilitating reflectometric detection of physiologic activity
Inventors
Gamble, Ronald C. • Weill, Lawrence Randolph • Monacos, Steve Perry
Assignees
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Publication Number
US-10987063-B2
Publication Date
2021-04-27
Expiration Date
Abstract
A method for remotely sensing cardiac-related data of an animal subject includes transmitting a RF signal to impinge on tissue of the subject, receiving a reflected portion of the RF signal, generating baseband data, filtering baseband data (e.g., including high pass filtering), performing waveform phase position determination, performing at least one auto-correlation of the waveform phase position determined data, determining periodicity of the auto-correlated data, and (i) computing heart rate using a maximum periodicity of the periodicity, or (ii) identifying abnormalities in cardiac function, such as may be indicated by temporal variations in heart rate and/or signal amplitude corresponding to cardiac activity. Multiple bandpass filtering schemes may be employed.
Core Innovation
The invention provides a contactless reflectometric system and method for cardiac sensing of an animal subject. A radio frequency signal is transmitted to impinge on tissue, and a reflected radio frequency signal is received that comprises a reflection of the transmitted radio frequency signal. Baseband data is generated utilizing the reflected radio frequency signal to support subsequent processing for cardiac activity.
The method filters data embodying or derived from the baseband data to yield initially filtered data, and the filtering includes high-pass filtering with a cutoff frequency of 10 Hz or greater. Waveform phase position determination is performed on data embodying or derived from the initially filtered data to yield waveform phase position determined data. Periodicity of data embodying or derived from the waveform phase position determined data is determined by determining at least one periodicity value indicative of cardiac activity.
The method compares at least one periodicity value indicative of cardiac activity for a selected interval with periodicity values for an interval preceding the selected interval and for an interval following the selected interval. It also supports detecting abnormalities in cardiac function by using temporal variations based on periodicity interval comparisons and by comparing information related to temporal changes in periodicity values with stored prior information.
Claims Coverage
The document includes one independent method claim and dependent claims. Across these claims, the inventive coverage is centered on generating cardiac periodicity values from reflectometric baseband data using high-pass filtering and waveform phase position determination, and then comparing periodicity values across time intervals for cardiac activity assessment.
Transmit RF to impinge on tissue and receive reflected RF
Transmitting a radio frequency signal to impinge on tissue of an animal subject; receiving a reflected radio frequency signal comprising a reflection of the radio frequency signal impinged on tissue of the subject.
Generate baseband data, then high-pass filter with cutoff ≥10 Hz
Generating baseband data utilizing the reflected radio frequency signal; filtering data embodying or derived from the baseband data to yield initially filtered data, including high-pass filtering with a cutoff frequency of 10 Hz or greater.
Waveform phase position determination to enable cardiac periodicity
Performing waveform phase position determination on data embodying or derived from the initially filtered data to yield waveform phase position determined data; determining periodicity of data embodying or derived from the waveform phase position determined data by determining at least one periodicity value indicative of cardiac activity.
Compare periodicity values across selected, preceding, and following intervals
Comparing the at least one periodicity value indicative of cardiac activity for a selected interval to at least one periodicity value indicative of cardiac activity for an interval preceding the selected interval and to at least one periodicity value indicative of cardiac activity for an interval following the selected interval.
Taken together, the claims cover reflectometric RF processing with high-pass filtering and waveform phase position determination to derive periodicity values indicative of cardiac activity, followed by interval-to-interval comparison and temporal variation analysis.
Stated Advantages
Enhanced visibility of cardiac abnormalities via appropriate filtering and periodicity-based interval comparison.
Cardiac detection is demonstrated as independent of respiration.
Supports screening workflows with follow-on cardiac tests.
Documented Applications
Contactless reflectometric heart rate computation and cardiac activity sensing of an animal subject, with comparison to electrocardiographic results.
Detection of cardiac abnormalities including premature heartbeat and weak, missed, or delayed heartbeat based on temporal variations in periodicity values indicative of cardiac activity.
Potential screening workflows with follow-on cardiac tests.
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