Heart valve abnormality detection device, non-transitory recording medium, and detection method
A heart valve abnormality detection device includes a heart sound data acquisition portion 21 configured to acquire heart sound data corresponding to heart sounds, a first processing portion configured to set, based on the heart sound data, a section between a first heart sound and a second heart sound of the heart sounds as a target range and acquire a peak frequency that is a peak value of a frequency in a frequency component of the heart sounds within the target range, and a second processing portion configured to output a detection signal indicating that there is a high probability of severe aortic stenosis in a case where the peak frequency is a peak reference value or greater.
1 . A heart valve abnormality detection device comprising:
a heart sound data acquisition unit configured to acquire heart sound data corresponding to heart sounds;
a first processing unit configured to acquire, based on the heart sound data, a peak frequency that is a peak value of a frequency in a frequency component of the heart sounds from a target range defined between a first heart sound and a second heart sound of the heart sounds;
an ejection time acquisition unit configured to acquire an ejection time based on the heart sound data;
a storage unit configured to store a first frequency that is a peak reference value for determining severe aortic stenosis (hereinafter as AS), a second frequency lower than the first frequency, and an ejection reference value; and
a second processing unit configured to output a detection signal D 5 indicating severe AS when both the peak frequency is the first frequency or more and the ejection time is equal to or longer than the ejection reference value, and output a detection auxiliary signal D 6 indicating moderate AS when both the peak frequency is lower than the first frequency and is equal to or higher than the second frequency and the ejection time is equal to or longer than the ejection reference value.
2 . The heart valve abnormality detection device according to claim 1 , wherein the first frequency is 300 Hz.
3 . The heart valve abnormality detection device according to claim 2 , wherein the second frequency is 180 Hz.
4 . The heart valve abnormality detection device according to claim 2 , wherein the second processing unit outputs a detection auxiliary signal D 6 a indicating suspected severe AS when the peak frequency is 150 Hz or greater and is smaller than 300 Hz.
5 . The heart valve abnormality detection device according to claim 1 , wherein the second processing unit outputs a detection auxiliary signal D 6 b indicating that echocardiography is to be performed when the peak frequency is 150 Hz or greater.
6 . The heart valve abnormality detection device according to claim 1 , wherein the target range is set to a range after 100 ms from a start of the first heart sound but not exceeding 500 ms.
7 . The heart valve abnormality detection device according to claim 1 , wherein, as the first frequency, a representative value that is determined based on a plurality of peak frequencies acquired from the target range for each of a plurality of pulse waves is used.
8 . The heart valve abnormality detection device according to claim 1 , wherein the ejection reference value is 280 ms.
9 . The heart valve abnormality detection device according to claim 1 , comprising a detection unit configured to detect, based on the heart sound data, ejection click occurring in a vicinity of the first heart sound, wherein
the second processing unit outputs the detection signal D 5 when, in addition to a condition that the peak frequency is the first frequency or more and the ejection time is equal to or longer than the ejection reference value, a condition that the ejection click is detected is satisfied, and outputs the detection auxiliary signal D 6 when, in addition to a condition that the peak frequency is lower than the first frequency and is equal to or higher than the second frequency and the ejection time is equal to or longer than the ejection reference value, a condition that the ejection click is detected is satisfied.
10 . The heart valve abnormality detection device according to claim 9 , wherein the detection unit detects a main frequency that is a frequency of a main component of the first heart sound, and detects the ejection click when the main frequency is a first heart sound reference value or greater.
11 . The heart valve abnormality detection device according to claim 10 , wherein the first heart sound reference value is 50 Hz.
12 . The heart valve abnormality detection device according to claim 1 , wherein, in acquiring the peak frequency, the first processing unit targets a frequency component of the heart sounds having an intensity equal to or greater than a reference intensity within the target range.
13 . The heart valve abnormality detection device according to claim 1 , wherein the first processing unit acquires the peak frequency by performing wavelet analysis on the heart sound data.
14 . The heart valve abnormality detection device according to claim 1 , wherein
the heart sound data acquisition unit includes
a normalization processing unit configured to normalize the heart sounds,
a noise removal unit configured to remove environmental noise, and
an amplification unit configured to perform amplification to a predetermined intensity level.
15 . The heart valve abnormality detection device according to claim 1 , wherein, in a state where the peak frequency is the second frequency or more and the ejection time is not equal to or longer than the ejection reference value, the detection auxiliary signal D 6 is output with a signal indicating the state incorporated in the detection auxiliary signal D 6 .
16 . The heart valve abnormality detection device according to claim 2 , wherein, in a state where the peak frequency is the second frequency or more and the ejection time is not equal to or longer than the ejection reference value, the detection auxiliary signal D 6 is output with a signal indicating the state incorporated in the detection auxiliary signal D 6 .
17 . The heart valve abnormality detection device according to claim 3 , wherein, in a state where the peak frequency is the second frequency or more and the ejection time is not equal to or longer than the ejection reference value, the detection auxiliary signal D 6 is output with a signal indicating the state incorporated in the detection auxiliary signal D 6 .
18 . The heart valve abnormality detection device according to claim 4 , wherein, in a state where the peak frequency is the second frequency or more and the ejection time is not equal to or longer than the ejection reference value, the detection auxiliary signal D 6 is output with a signal indicating the state incorporated in the detection auxiliary signal D 6 .
19 . The heart valve abnormality detection device according to claim 9 , wherein, in a state where the peak frequency is the second frequency or more and either the ejection time is not equal to or longer than the ejection reference value or the ejection click is not detected, the detection auxiliary signal D 6 is output with a signal indicating the state incorporated in the detection auxiliary signal D 6 .
20 . A non-transitory recording medium storing a computer readable program used in a computer, the computer readable program causing the computer to perform processing comprising:
first processing for acquiring heart sound data corresponding to heart sounds;
second processing for acquiring, based on the heart sound data, a peak frequency that is a peak value of a frequency in a frequency component of the heart sounds from a target range defined between a first heart sound and a second heart sound of the heart sounds;
third processing for acquiring an ejection time based on the heart sound data;
fourth processing for storing a first frequency that is a peak reference value for determining severe aortic stenosis (hereinafter as AS), a second frequency lower than the first frequency, and an ejection reference value; and
fifth processing for outputting a detection signal D 5 indicating severe AS when both the peak frequency is the first frequency or more and the ejection time is equal to or longer than the ejection reference value, and outputting a detection auxiliary signal D 6 indicating moderate AS when both the peak frequency is lower than the first frequency and is equal to or higher than the second frequency and the ejection time is equal to or longer than the ejection reference value.
21 . A method for detecting an abnormality in a heart valve by processing heart sound data corresponding to heart sounds, the method comprising:
performing first processing of acquiring, based on the heart sound data, a peak frequency that is a peak value of a frequency in a frequency component of the heart sounds from a target range defined between a first heart sound and a second heart sound of the heart sounds;
performing ejection time acquisition processing of acquiring an ejection time based on the heart sound data; and
performing second processing of using a first frequency that is a peak reference value for determining severe aortic stenosis (hereinafter as AS), a second frequency lower than the first frequency, and an ejection reference value that are stored in a storage unit to output a detection signal D 5 indicating severe AS when both the peak frequency is the first frequency or more and the ejection time is equal to or longer than the ejection reference value, and output a detection auxiliary signal D 6 indicating moderate AS when both the peak frequency is lower than the first frequency and is equal to or higher than the second frequency and the ejection time is equal to or longer than the ejection reference value.