JP2017169615A - Systolic phase cardiac murmur detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device that allows a cardiac murmur that may indicate a disease such as aortic stenosis to be automatically detected without requiring experience.SOLUTION: A systolic phase cardiac murmur detection device includes an electrocardiogram signal reception part for receiving an electrocardiogram signal, a cardiac sound signal reception part for receiving a cardiac sound signal, a systolic phase extraction part for extracting a time of a cardiac systolic phase from the electrocardiogram signal, and a systolic phase cardiac murmur determination part for detecting whether or not a sound other than the first sound and/or the second sound is present in a cardiac sound in the time extracted by the systolic phase extraction part from a cardiac sound signal, and determines whether or not a cardiac murmur is present based on the detection result.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an apparatus for detecting cardiac noise during a systole of a heart from an electrocardiogram signal and a heart sound signal.

  Aortic stenosis is a cause of sudden death, fainting, chest pain, and heart failure, and prior diagnosis is important. For diagnosis of aortic stenosis, doctors usually determine whether there is an abnormal heart noise by auscultation, and if there is an abnormality, follow a procedure such as performing an echocardiogram. .

By the way, although it is predicted that visiting nursing and telemedicine will expand in the future, it is necessary to have experience to judge cardiac noise that may cause aortic stenosis by auscultation. Currently, there are overwhelmingly few human resources available. In addition, heart noise that may cause aortic stenosis occurs in the systole of the heart, but such heart noise also occurs in diseases such as mitral regurgitation and ventricular septal defect. It can also be used to determine such diseases.
In view of such a problem, an object of the present invention is to provide an apparatus capable of automatically detecting cardiac noise that may cause a disease such as aortic stenosis without experience.

In order to solve the above problems, the present invention has the following configuration.
The invention described in claim 1 includes an electrocardiogram signal receiving unit that receives an electrocardiogram signal, a heart sound signal receiving unit that receives a heart sound signal, and a systolic phase extracting unit that extracts the approximate systolic time of the heart from the electrocardiogram signal; The systolic heart noise detecting device includes a systolic heart noise determining unit that determines whether or not heart noise is present in the heart sound at the time extracted by the systolic extracting unit from the heart sound signal. The signal in the present application includes both an analog signal and a digital signal (data). In the present application, the electrocardiogram signal is sufficient as a minimum electrocardiogram signal that can determine the systole and diastole of the heart, and the heart sound signal is a sound obtained from a body surface near the heart via a sound collector such as a stethoscope. Signal.
According to a second aspect of the present invention, in the systolic heart murmur detection device, the systolic heart murmur determination unit includes one sound and / or one in the heart sound at a time extracted from the heart sound signal by the systolic extraction unit. Alternatively, it is detected whether there is a sound other than two sounds, and it is determined whether there is heart noise based on the detection result. Note that one sound and two sounds are generally represented by Roman numerals, but here they are represented by Chinese numerals because of the character limitation of the patent application software. Also, in the actual heart, two sounds are generated when the systole and diastole are switched, so depending on the systolic extraction method by the systolic extraction part, two sounds may not be included. The systolic heart murmur determination unit does not need to detect whether a sound other than two sounds is present.
According to a third aspect of the present invention, in the systolic heart noise detection device according to the second aspect, the systolic noise determination unit has the same sound other than the one sound and / or two sounds in a plurality of systolic periods. When it is detected at the timing, it is determined that there is cardiac noise.
According to a third aspect of the present invention, in the systolic heart murmur detection device according to the third aspect, sounds other than the one sound and / or two sounds are detected at the same timing in the time of ten or more consecutive systoles. In this case, it is determined that there is heart noise.
According to a fourth aspect of the present invention, in the systolic heart noise detecting device according to the second or third aspect, in the case of detecting whether or not a sound other than one sound exists, the systolic heart noise detecting device The systolic heart murmur determination unit is configured to generate a sound other than the one sound and / or two sounds when a sound having an amplitude exceeding a predetermined threshold is present after a predetermined time has elapsed from the start of the systole to the end of the systole. Is detected.
According to a fifth aspect of the present invention, in the systolic heart noise detecting device according to any one of the second to fourth aspects, when it is detected whether a sound other than one sound is present, the systolic heart noise is detected. When the determination unit detects whether there is a sound other than two sounds, the sound having an amplitude exceeding a predetermined threshold is present between the start of the systole and a predetermined time before the end of the systole. It detects the presence of a sound other than two sounds.
The invention according to claim 6 is a program for causing a computer to realize a function as the systolic heartbeat detection device. The computer includes various devices such as a smart phone, a tablet computer, and a portable information terminal that have a CPU and a function that operates by incorporating a program.

With the configuration as described above, the present invention has the following effects.
According to the first and second aspects of the present invention, it is possible to automatically obtain a heart murmur during the systole of the heart that occurs in a disease such as aortic valve stenosis. Then, by determining whether or not the systole is based on the electrocardiogram data, it is possible to make an accurate and automatic determination.
The invention according to claim 3 can reduce misjudgment due to normal noise such as breathing sound by measuring the systole multiple times.
The invention according to claim 4 can reduce erroneous determination due to breathing sound or the like more reliably by measuring the systole 10 times or more.
According to the fifth aspect of the present invention, since one sound having a peak at the start of the systole attenuates in a short time from the systole, whether or not there is a sound having an amplitude greater than or equal to a predetermined threshold in the systole except this period. Therefore, it is possible to easily extract a sound other than a single sound that may cause heart noise.
According to the sixth aspect of the invention, since two sounds are generated at the end of the systole, if it is determined whether there is a sound having an amplitude equal to or greater than a predetermined threshold in the systole except for this period, two sounds are easily obtained. It is possible to extract sounds other than sounds that have the possibility of heart noise.
The invention according to claim 7 is a non-medical worker who is not in a medical institution or a medical examination center by himself / herself in a systolic heart by incorporating the program such as a smartphone and connecting a terminal capable of acquiring electrocardiogram data and electrocardiogram data. Noise can be measured.

It is a block diagram which shows typically the hardware constitutions of the systolic heart noise detection apparatus which concerns on embodiment. (A) is a perspective view of the surface side which shows the example of the stethoscope with the electrode for electrocardiograms, (b) is a perspective view of the back side which shows the example of the stethoscope with the electrodes for electrocardiogram. It is a functional block diagram which shows typically the function of a systolic heart noise detection apparatus. (A) is a figure which shows an example of an electrocardiogram signal, (b) is a figure which decomposes | disassembles and shows an example of a heart sound signal. It is a flowchart which shows operation | movement of a systolic heart noise detection apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram schematically showing the hardware configuration of the systolic heart noise detection device X according to the embodiment. The systolic heartbeat detection device X stores a CPU 11 that performs arithmetic processing, a RAM 12 that is a work area of the CPU, a ROM 13 that stores basic programs and data, a clock 14 that takes CPU operation timing, and data and programs. Connected to an external recording device 15 such as an SSD, a monitor 16 having a touch panel for inputting data and displaying information, electrocardiogram electrodes 20a, 20b and 20c of a stethoscope Y with an electrocardiogram electrode to be described later, and an auscultation unit 30 And an analog interface 17 including an AD converter. The systolic heart murmur detection device X is formed by incorporating a program for realizing the operation described below into such hardware. In addition, these hardware is stored in the housing | casing formed with the metal and the synthetic resin.

  FIG. 2A shows a perspective view of the distal end portion of the stethoscope Y with an electrocardiogram electrode connected to the analog interface 17 as viewed obliquely from above, and FIG. 2B shows the distal end portion of the stethoscope Y with an electrocardiogram electrode obliquely downward. The perspective view seen from is shown. The stethoscope Y with an electrocardiogram electrode includes three electrocardiogram electrodes 20a, 20b, 20c, an auscultation unit 30, and an electric cable 40. The auscultation unit 30 has substantially the same structure as a chest piece portion of a general diaphragm type stethoscope, but has a built-in microphone for converting sound into an electrical signal. The electrocardiogram electrodes 20a, 20b, and 20c are electrodes arranged in a regular triangle around the auscultation unit 30, and constitute a plus electrode, a minus electrode, and a ground electrode, respectively. The electrocardiogram electrodes 20a, 20b, and 20c are fixed in an elastomer cover that is integrally fixed to the auscultation unit 30 on the back side, the exposed surfaces of the electrocardiogram electrodes 20a, 20b, and 20c and the diaphragm of the auscultation unit 30 The surface of the electrocardiogram electrode 20a, 20b, and 20c is exposed to the body when the diaphragm surface of the auscultation unit 30 is brought into contact with the body surface of the heart portion. It is formed so as to be in proper contact with the surface. The electric wires electrically connected to the electrocardiogram electrodes 20a, 20b, and 20c and the electric wires connected to the microphone built in the auscultation unit 30 are connected to the analog interface 17 of the systolic heart noise detector X via the electric cable 40. The

FIG. 3 is a functional block diagram schematically showing the function of the systolic heart noise detector X. It has an electrocardiogram signal reception unit 101, an electrocardiogram signal reception unit 102, a systolic extraction unit 103, and a cardiac noise determination unit 104.
The electrocardiogram signal receiving unit 101 receives an electrocardiogram signal transmitted from the electrocardiogram electrodes 20a, 20b, and 20c of the stethoscope Y with the electrocardiogram electrode. FIG. 4A shows an example of an electrocardiogram obtained based on the electrocardiogram electrodes 20a, 20b, and 20c. There are P waves, Q waves, R waves, S waves, and T waves in the electrocardiogram. From the peak of the R wave, the end of the T wave is the systole of the heart, and the other is the diastole of the heart.
The heart sound signal receiving unit 102 receives a signal sent from the built-in microphone of the auscultation unit 30 of the stethoscope Y with an electrocardiogram electrode. FIG. 4B shows an example of sounds around the heart collected by the auscultation unit 30. A heart sound is a sound generated with the heartbeat and is generated as an I sound (single sound), an II sound (two sounds), a III sound (three sounds), or an IV sound (four sounds). Of these, the I sound (one sound) occurs immediately after the start of the systole of the heart, and the II sound (two sounds) occurs at the boundary between the systole and the diastole. The heart murmur is a sound that occurs with the heartbeat but does not occur in a normal heart. The systolic heart murmur detector X aims to detect this murmur during systole. A breathing sound or the like is a normal sound generated by an internal activity such as breathing in addition to the heart. Since the auscultation unit 30 converts a sound in which these sounds are overlapped into an electric signal with a microphone, the heart sound signal received by the heart sound data receiving unit 102 is received as a multiple of sounds around the heart.

The systole extraction unit 103 extracts the systole of the heart based on the electrocardiogram signal received by the electrocardiogram signal reception unit 101. Specifically, an R wave and a T wave are extracted from the electrocardiogram shown in FIG. 4A, and a period from the peak of the R wave to the end of the T wave is defined as a systole. However, since the II sound (two sounds) is generated at the end of the T wave, the time from the end of the T wave until the end of the systole is set so that the II sound (two sounds) is not included here. Suddenly.
The cardiac noise determination unit 104 determines whether there is cardiac noise in the systole extracted by the systolic determination unit 103. The cardiac noise determination unit 104 includes a cardiac noise detection unit 104a and a determination unit 104b. The cardiac noise detection unit 104a detects whether there is a sound having an amplitude exceeding a predetermined threshold between 0.3 seconds after the start of the systole extracted by the systole extraction unit 103 and the end of the systole. The threshold value can be appropriately set such as obtaining from the amplitude of the I sound (one sound) or using an absolute value obtained by an experiment or the like. The reason for determining from 0.3 seconds after the start of the systole is that the I sound (one sound) always exists as a loud sound at the beginning of the systole, so that the time until it becomes sufficiently small is excluded. is there. Since this time is influenced by the pulse rate and the like, it is not limited to 0.3 seconds, but can be changed as appropriate, and may vary depending on the pulse rate. If there is a sound that exceeds the threshold, the cardiac noise detection unit 104a records the generation timing within the systole. The determination unit 104b determines that there is cardiac noise when the cardiac noise detection unit 104a performs detection in 10 consecutive systoles, and there is a sound that exceeds the threshold at the same timing in all 10 times. . The determination based on the ten systoles is to eliminate the influence of noise such as breathing sound, and the influence of the breathing sound can be eliminated by measuring about ten times from the breathing timing. The number of times is not limited to 10 and may be changed as appropriate. In addition, the determination criterion that there is a sound that exceeds the threshold value in all ten systoles is also an example, and the determination condition is also changed as appropriate, such as determining that there is cardiac noise even when the frequency threshold value less than 10 is exceeded. Can do.

Next, the operation of the systolic heart noise detection device X having the above configuration will be described. 6 is a flowchart showing the operation according to FIG. First, the examiner consults the stethoscope Y with the electrocardiogram electrode so that the auscultation unit 30 and the electrocardiogram electrodes 20a to 20c are in firm contact with the body surface of the examinee with the electrocardiogram electrode 20a facing down. Press against the person's heart. As a result, an electrocardiogram signal is sent from the electrocardiogram electrodes 20a to 20c, and a heart sound signal is sent from the auscultation unit 30 to the systolic heart noise detection device X. Therefore, the electrocardiogram signal reception unit 101 receives the electrocardiogram signal, and the heart sound signal The accepting unit 102 accepts a heart sound signal (s101). The systolic extraction unit 103 extracts the systole of the heart based on the accepted electrocardiogram signal (s102). Next, the heart noise detection unit 104 of the heart noise determination unit 104 increments the variable corresponding to the number of examinations by one (s103), and the heart sound received in the period excluding the first 0.3 seconds of the extracted systole. It is determined whether the amplitude of the signal exceeds a predetermined threshold (s104). If the threshold is not exceeded, the determination unit 104b determines that there is no cardiac noise. When the threshold value is exceeded in s104, the cardiac noise detection unit 104a records the timing in excess (s105). The above operations from s103 to s105 are repeated until the variable becomes 10 (s106). When the variable is 10, that is, when 10 operations are completed, the determination unit 104b of the cardiac noise determination unit 104 has a timing when the threshold is exceeded. Are all the same in 10 times. (S107). Here, if all have the same timing, it is determined that there is cardiac noise (s108), and if there is a different timing, it is determined that there is no cardiac noise (s109). Thereafter, the determination result by the cardiac noise determination unit 104 is displayed on the monitor 16 and recorded in association with the examinee information (s110), and the process ends.
As described above, the systolic heart murmur detection device X according to the present embodiment detects the systolic heart murmur that has been extracted by human experience, and extracts the systolic rhythm of the heart from the electrocardiogram signal. By using this, it is possible to automatically determine whether there is heart noise during the systole.

In the above embodiment, the systolic heart noise detection device is exemplified as a dedicated device. For example, application software that realizes the above operation is incorporated in a smartphone, and an electrocardiogram electrode is formed so as to be connectable to the smartphone. By connecting a stethoscope to a smartphone, the smartphone can be used as a systolic heartbeat detection device. This makes it possible for the examinee himself to easily detect systolic heart noise at home.
Further, in the above embodiment, a stethoscope with an electrocardiogram electrode is connected to the systolic heart noise detection device so as to directly receive an electrocardiogram signal and a heart sound signal. Can be read through a USB memory or a communication line and used to detect cardiac noise during systole.
Further, in the above embodiment, the electrocardiogram signal and the heart sound signal are analyzed by the CPU as digital data, but it is also possible to perform the analog signal as it is until it is determined whether the heart sound signal exceeds the threshold value.
Then, when the heart noise detection unit detects whether the heart sound signal exceeds the threshold value 10 times, after acquiring the electrocardiogram signal and the heart sound signal at the heart rate of 10 times, it is determined whether the threshold value is exceeded each time. Alternatively, each time an electrocardiogram signal and a heart sound signal corresponding to one heartbeat are received, it may be detected whether the heart sound signal exceeds a threshold value.
Then, in the above embodiment, in order to eliminate the I sound (single sound), it is detected whether the heart sound signal exceeds the threshold value after 0.3 second of the systole, but the I sound (single sound). Is not limited to this, for example, an I sound (one sound) is estimated based on 10 heart sound signals at the peak of the R wave of the electrocardiogram, and this waveform is subtracted from the heart sound signal, Other methods such as determining whether or not the threshold value is exceeded with respect to the value obtained by subtracting the average I sound waveform data may be employed.
Further, in the above embodiment, the end time is extracted slightly earlier so that the II sound (two sounds) is not included in the systole, but the time until the II sound (two sounds) is included is extracted as the systole. Alternatively, processing may be performed so as not to be confused with heart noise by subtracting the estimated waveform of the II sound (two sounds).

X Systolic heart noise detection device Y Stethoscopes 20a, 20b, 20c with electrocardiogram electrodes Electrocardiogram electrode 30 Auscultation unit 101 Electrocardiogram signal reception unit 102 Heart sound signal reception unit 103 Systole extraction unit 104 Heart noise determination unit 104a Heart noise detection unit 104b Judgment part

Claims (7)

An electrocardiogram signal receiving unit for receiving an electrocardiogram signal;
A heart sound signal receiving unit for receiving heart sound signals;
A systolic extraction unit that extracts the approximate systolic time of the heart from the electrocardiogram signal;
A systolic heart noise detecting device comprising: a systolic heart noise determining unit that determines whether heart noise is present in a heart sound at a time extracted by the systolic extracting unit from the heart sound signal.   The systolic heart noise determination unit detects from the heart sound signal whether there is a sound other than one sound and / or two sounds in the heart sound at the time extracted by the systolic extraction unit, and based on the detection result The systolic heart noise detection device according to claim 1, wherein it is determined whether or not heart noise is present.   The said systolic noise judgment part judges that cardiac noise exists when sounds other than said one sound and / or two sounds are detected at the same timing in the time of a plurality of systolic periods. Systolic heart murmur detector.   4. The systolic noise determination unit determines that there is cardiac noise when sounds other than the one sound and / or two sounds are detected at the same timing in ten or more consecutive systolic times. The systolic heart murmur detection device described in 1.   When detecting whether there is a sound other than a single sound, the systolic heart murmur determination unit has a sound with an amplitude exceeding a predetermined threshold between the start of the systole and the end of the systole after the start of the systole. 5. The systolic heart noise detection device according to claim 2, wherein the presence of a sound other than the one sound is detected when the sound is present.   When detecting whether there is a sound other than two sounds, the systolic heart murmur determining unit detects a sound having an amplitude exceeding a predetermined threshold between a start of the systole and a predetermined time before the end of the systole. The systolic heart noise detection device according to any one of claims 2 to 5, wherein the presence of a sound other than the two sounds is detected when it exists.   The program which makes a computer implement | achieve the function as a systolic heart noise detection apparatus of any one of Claim 1 to 6.

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