US 12,733,898 B2Granted

Medical decision support system

AssigneeAusculsciences, Inc.

InventorsMarina Vernalis, Brian J. Booth, Fatma Usta, Bahareh Taji, David Gloag, Sergey A. Telenkov, Robin F. Castelino

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Abstract

At least one swing value is determined responsive to a difference between maximum and minimum amplitude values of an auscultatory sound signal within a temporal region of a heart-cycle segment spanning an entire heart cycle of an auscultatory sound signal, wherein a location of at least one temporal region is responsive to a duration of the heart-cycle segment. S4 sound presence is detected responsive to a ratio of S4SWING to S2SWING in relation an associated median value thereof from a population of test-subjects. A Support Vector Machine trained responsive to age, sex, S4 presence and a plurality of heart sound swing measures provides for detecting CAD. Unsupervised classification of an S3swing and median and mean values of a Short Time Fourier Transform within associated frequency intervals, based upon data from a plurality of heart cycles of a plurality of test-subject provides for detecting presence of an S3 sound.

Claims78

Dependent claims

A computer-implemented method of detecting an S4 heart sound in an auscultatory sound signal, comprising:

a. receiving an electrographic signal from an electrocardiogram (ECG) sensor;
b. receiving at least one auscultatory sound signal responsive to a corresponding at least one auscultatory sound-or-vibration sensor operatively associated with a test-subject;
c. segmenting said at least one auscultatory sound signal responsive to said electrographic signal so as to associate a plurality of heart-cycle time series with said at least one auscultatory sound signal, wherein each heart-cycle time series of said plurality of heart-cycle time series spans a single corresponding heart cycle;
d. for said each heart-cycle time series of said plurality of heart-cycle time series:
i. locating an S2-sound time interval within said each heart-cycle time series, wherein an end of said S2-sound time interval is assumed to occur at a start of a diastasis time interval, and a start of said S2-sound time interval is assumed to occur at a midpoint between a start of said each heart-cycle time series and said end of said S2-sound time interval;
ii. determining an S2 swing value of said each heart-cycle time series, wherein said S2 swing value is given by an absolute value of a difference between maximum and minimum values of said each heart-cycle time series within said S2-sound time interval;
iii. locating an S4-sound time interval within said each heart-cycle time series, wherein an end of said S4-sound time interval is assumed to occur at an end of said each heart-cycle time series, and a start of said S4-sound time interval is assumed to occur at a point in time that is 80 percent of a duration of said each heart-cycle time series;
iv. determining an S4 swing value of said each heart-cycle time series, wherein said S4 swing value is given by an absolute value of a difference between maximum and minimum values of said each heart-cycle time series within said S4-sound time interval;
and
v. determining an S4S2 swing ratio of said each heart-cycle time series, wherein said S4S2 swing ratio is given by a ratio of said S4 swing value and said S2 swing value;
and
e. for said each heart-cycle time series of said plurality of heart-cycle time series, determining a value of a fraction of said each heart-cycle time series of said plurality of heart-cycle time series for which a corresponding said S4S2 swing ratio exceeds a predetermined mean value of said S4S2 swing ratio, wherein said fraction of said each heart-cycle time series is in relation to a total number of said each heart-cycle time series of said plurality of heart-cycle time series, if said value of said fraction of said each heart-cycle time series is in excess of a first threshold, then indicating that said test-subject exhibits the S4 heart sound, otherwise indicating that said test-subject does not exhibit said S4 heart sound.

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