JP2011212364A - Cardiac sound measuring device - Google Patents

Abstract

Provided is a heart sound measuring device capable of accurately discriminating a heart cycle while avoiding the influence of pulse wave propagation time based on a pulse wave and accurately identifying the type of heart sound or heart noise.
In this heart sound measuring device, a cardiac cycle time division unit (6) is based on a pulse wave propagation time T determined by a pulse wave propagation time determination unit (11) and a pulse wave signal from a pulse wave detection unit (3). Since the divided periods Q11 to Q23 of the cardiac cycle TH are defined, the cardiac cycle TH and the divided periods Q11 to Q23 can be accurately defined in consideration of the pulse wave propagation time T. Therefore, the cardiac cycle time division unit 6 is not affected by the pulse wave propagation time T even when a peripheral site such as a wrist, finger, or ankle where the pulse wave detection unit 3 is relatively easy to wear is used as a measurement site. The heart cycle can be accurately defined. Therefore, the heart sound specifying unit 7 and the heart noise specifying unit 8 can specify in which divided period among the plurality of divided periods of the heart cycle that are accurately defined, the heart sound band signal and the heart noise band signal.
[Selection] Figure 1

Description

  The present invention relates to a heart sound measuring apparatus that extracts and measures heart sounds and heart noises from sounds generated from a living heart.

  Since heart sounds include various types of excessive heart sounds and heart noises caused by heart disease, in order to detect signs of heart disease at an early stage, heart sounds are measured on a daily basis. It is desirable to check for noise.

  For the evaluation of heart disease due to heart sounds, the auscultation method in which a doctor auscultates using a stethoscope is the mainstream, and diagnosis by this auscultation method requires specialized knowledge. It is extremely difficult to perform on a daily basis, and it is not realistic to receive auscultation by a doctor on a daily basis.

  For this reason, it is desired that an apparatus capable of easily and routinely confirming the presence or absence of excessive heart sounds and heart noise on a daily basis by a general person without specialized knowledge at home is desired.

  Conventionally, as an alternative to auscultation, a heart sound meter has been devised that measures a heart sound or heart noise from a measured heart sound signal by attaching a microphone (heart sound sensor) that measures the heart sound to the body surface such as the chest wall (patented) Document 1 (Japanese Patent Laid-Open No. 3-133426), Patent Document 2 (Japanese Patent No. 3952608)).

  In these heart sound meters, heart sounds and heart noises are extracted from the measured heart sound signals to evaluate heart disease, and the extracted heart sounds and heart noises are recorded at any point in the cardiac cycle (ventricular systole and diastole). It is necessary to determine whether it occurs at (phase).

  As a method for discriminating the phase of the heart sound or heart noise in the cardiac cycle, the difference in time interval between the heart sound I sound (S1) and the II sound (S2) that are alternately observed in the heart sound signal is determined. Techniques have also been proposed. In this discrimination method, a period in which the time interval between the heart sounds I and II is short is a systole, and a period in which the time interval is long is an diastole.

  However, as described in the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 3-133426), depending on the symptoms of heart disease, the time interval between the systole and the diastole is equal, or the diastole is better. It may be shorter than the systole. Therefore, in reality, there is a problem that erroneous determination is likely to occur when the systole and diastole of the cardiac cycle are determined from only the heart sound signal.

  For this reason, as shown in Patent Document 1 and Patent Document 2 described above, a technique is used in which an electrocardiogram signal is measured simultaneously with a heart sound signal, and a cardiac cycle is discriminated based on the electrocardiogram signal. .

  As another method other than using an electrocardiogram signal, Patent Document 3 (Japanese Patent Publication No. 2008-534228) discloses a heart sound signal and pulsation (carotid artery wave, radial artery pulsation, brachial artery pulsation). 1) and a heart gating system and method for identifying a heart sound I sound (S1) and a II sound (S2) and transmitting a gating signal corresponding to the II sound (S2) to a cardiac imaging device. Has been proposed.

  By the way, in the method of discriminating the cardiac cycle based on the electrocardiogram signal as in Patent Document 1 and Patent Document 2, in addition to mounting at least one microphone (heart sound sensor) for measuring heart sounds, It is necessary to attach the electrodes for electrocardiogram measurement to two or three places of the living body. When it is assumed that the general person uses at home, etc., these plural electrocardiograph electrodes are used by the user himself / herself. Wearing it is cumbersome and not suitable for daily use over a long period of time.

  On the other hand, in the technique of using pulsation (pulse wave) without using electrocardiogram as in Patent Document 3, it is not necessary to attach a plurality of electrodes for electrocardiogram measurement. Instead, a pulse wave that measures pulse waves. Since only one sensor needs to be attached to an arbitrary measurement site such as the upper arm or the wrist skull, it is considered that it can be used relatively easily when a general person uses it daily at home. It is done.

  However, when the electrocardiogram signal is used as a reference as in Patent Document 1 and Patent Document 2, the cardiac cycle can be accurately captured (the R wave of the electrocardiogram signal is used as the start point of the systole). In the case of using pulsation (pulse wave) as in Patent Document 3, the pulse wave propagates from the aortic origin to the peripheral pulse wave measurement site. There is a possibility that the I sound (S1) and the II sound (S2) cannot be correctly identified depending on the time required for the time (pulse wave propagation time).

  Specifically, when using a peripheral measurement site such as a wrist, finger, or ankle, where the pulse wave sensor is relatively easy to wear, the distance from the aortic root is increased. As a result, the value of the pulse wave propagation time increases, and the pulse waveform shifts to a position that is delayed in time, so that the period between the I sound (S1) and the II sound (S2) of the heart sound (that is, the original sound) There is a possibility that the peak of the pulse waveform that should appear in the systole appears after the II sound (S2).

  In such a case, the I sound (S1) and the II sound (S2) are mistakenly identified, but the pulse rate is particularly slow (ie, the pulse wave propagation time is long) and the heart rate is high. If it is high, there is a high possibility that such a problem will occur. For example, if the pulse wave propagation speed is 400 cm / second and the distance from the aortic root to the pulse wave measurement site is 80 cm (such as the fingertip of a hand), the pulse wave propagation time takes about 200 milliseconds. When the number is 120 times / minute, if the time ratio between systole and diastole in the cardiac cycle is 4: 6, the systole is about 200 milliseconds (depending on individual differences and physical condition, the time ratio of the systole is further The peak of the pulse waveform may appear in the diastole after the II sound (S2).

  Also, if you want to determine the cardiac cycle more precisely (for example, six cardiac cycles: early systole, mid systole, late systole, early diastole, mid diastole, and late diastole), the time per cardiac cycle will be shortened. Therefore, the influence of the pulse wave propagation time as described above is further increased, and there is a high possibility that the cardiac cycle cannot be correctly identified.

  Further, Patent Document 3 discriminates the I sound (S1) and the II sound (S2) and transmits a gating signal corresponding to the II sound (S2), and uses pulsation (pulse wave). Therefore, it is not considered to identify heart sounds and heart noises other than I and II sounds, and excess heart sounds and heart noises cannot be identified.

Japanese Patent Laid-Open No. 3-133426 Patent No. 3952608 Special table 2008-534228 gazette

  SUMMARY OF THE INVENTION An object of the present invention is to provide a heart sound measuring device that can accurately determine the heart cycle based on the pulse wave while avoiding the influence of the pulse wave propagation time, and can accurately identify the type of heart sound or heart noise. is there.

In order to solve the above problems, a heart sound measuring device of the present invention detects a sound generated from the heart of a living body and outputs a heart sound signal as a heart sound signal;
A heart sound band extraction unit that extracts and outputs a component corresponding to the frequency of the heart sound from the heart sound signal;
A pulse wave detector for detecting a pulse wave of a certain part of the living body and outputting it as a pulse wave signal;
A pulse wave propagation time determining unit for determining a pulse wave propagation time for the pulse wave to propagate from the aorta starting part of the living body to the partial position;
Based on the pulse wave propagation time determined by the pulse wave propagation time determination unit and the pulse wave signal, a cardiac cycle time division unit that defines a division period in which the cardiac cycle of the heart is divided into a plurality of times;
The heart sound band signal, which is a component extracted by the heart sound band extraction unit, is identified as being in any one of a plurality of divided periods defined by the heart cycle time division unit, and the heart sound based on the heart sound band signal And a heart sound specifying unit for specifying the type.

  According to the heart sound measuring apparatus of the present invention, the cardiac cycle time division unit calculates the division period of the cardiac cycle based on the pulse wave propagation time and the pulse wave signal determined by the pulse wave propagation time determination unit. Therefore, the cardiac cycle and its divided period can be accurately defined in consideration of the pulse wave propagation time. Therefore, even when the peripheral part such as the wrist, finger, and ankle is used as the measurement part, which is relatively easy to mount the pulse wave detection part, the cardiac cycle time division part is not affected by the pulse wave propagation time. Thus, the heart cycle can be accurately defined. Therefore, the heart sound specifying unit can specify in which divided period of the plurality of divided periods of the accurately specified heart cycle the heart sound band signal is present, and accurately specify the type of heart sound based on the heart sound band signal. It becomes possible to identify.

Further, in the heart sound measuring device of one embodiment, a heart noise band extracting unit that extracts and outputs a component corresponding to a frequency of heart noise from the heart sound signal;
The cardiac noise band signal, which is a component extracted by the cardiac noise band extraction unit, is specified in which of the plurality of divided periods defined by the cardiac cycle time division unit, and the cardiac noise band And a cardiac noise identifying unit that identifies the type of cardiac noise caused by the signal.

  According to the heart sound measuring device of this embodiment, the cardiac noise specifying unit can accurately specify in which divided period of the divided periods of the cardiac cycle the cardiac noise band signal is, The type can be accurately identified.

Further, in the heart sound measurement device of one embodiment, a heart sound detection unit that detects a sound generated from the heart of a living body and outputs it as a heart sound signal;
A cardiac noise band extracting unit that extracts and outputs a component corresponding to the frequency of cardiac noise from the cardiac sound signal;
A pulse wave detector for detecting a pulse wave of a certain part of the living body and outputting it as a pulse wave signal;
A pulse wave propagation time determining unit for determining a pulse wave propagation time for the pulse wave to propagate from the aorta starting part of the living body to the partial position;
Based on the pulse wave propagation time determined by the pulse wave propagation time determination unit and the pulse wave signal, a cardiac cycle time division unit that defines a division period in which the cardiac cycle of the heart is divided into a plurality of times;
The cardiac noise band signal, which is a component extracted by the cardiac noise band extraction unit, is specified in which of the plurality of divided periods defined by the cardiac cycle time division unit, and the cardiac noise band And a cardiac noise identifying unit that identifies the type of cardiac noise caused by the signal.

  According to the heart sound measuring device of this embodiment, the cardiac cycle time division unit is configured to divide the cardiac cycle based on the pulse wave propagation time and the pulse wave signal determined by the pulse wave propagation time determination unit. Therefore, it is possible to accurately define the cardiac cycle and its divided period in consideration of the pulse wave propagation time. Therefore, even when the peripheral part such as the wrist, finger, and ankle where the pulse wave detection unit is relatively easy to install is used as the measurement site, the cardiac cycle time division unit is not affected by the pulse wave propagation time. Can specify the cardiac cycle. Therefore, the cardiac noise specifying unit can specify in which divided period of the plurality of divided periods of the precisely defined cardiac cycle the cardiac noise band signal is present. The type can be accurately identified.

  In the heart sound measuring device of one embodiment, the result of determining the presence or absence of abnormality of the detected heart sound signal based on the type of heart sound by the heart sound band signal specified by the heart sound specifying unit is output as determination result information. A heart sound determination unit; and a heart sound determination result output unit that presents the determination result information to the user.

  According to the heart sound measuring apparatus of this embodiment, the result of determining the presence or absence of abnormality of the heart sound signal by the heart sound determination unit is output as determination result information by the heart sound determination result output unit and presented to the user. Since it is possible to show the user whether or not the heart sound signal contains excessive heart sounds that may appear when there is some abnormality in the surrounding circulatory system, etc., the user can indicate whether or not the heart sound signal is abnormal. It becomes possible to confirm easily.

  Further, in the heart sound measuring device of one embodiment, the result of determining the presence or absence of abnormality of the detected heart sound signal based on the presence or absence of heart noise due to the heart noise band signal specified by the heart noise specifying unit is determination result information. And a cardiac noise determination result output unit for presenting the determination result information to the user.

  According to the heart sound measuring apparatus of this embodiment, the result of determining the presence or absence of abnormality of the heart sound signal by the heart noise determination unit is output as determination result information by the heart noise determination result output unit and presented to the user. Therefore, it is possible to present to the user whether or not heart noise that may appear when there is any abnormality in the circulatory system around the heart is included in the heart sound signal. The presence / absence can be easily confirmed.

Further, in the heart sound measuring device of one embodiment, the cardiac noise determination unit is
Results of determining the presence or absence of detected heart sound signal and the type of abnormality of the heart sound signal based on the presence or absence of heart noise due to the heart noise band signal specified by the heart noise specifying unit and the type of heart noise Is output as determination result information.

  According to the heart sound measuring device of this embodiment, the heart noise determination unit outputs the result of determining the presence / absence of abnormality of the heart sound signal and the type of abnormality of the heart sound signal as determination result information by the heart noise determination result output unit. And presenting it to the user, whether the heart sound signal includes heart noise that may appear when there is some abnormality in the circulatory system around the heart, and the type of the heart noise Since the information can be presented to the user, the user can easily confirm the presence / absence of the heart sound signal and the type of abnormality.

Further, in the heart sound measuring device of one embodiment, the heart sound determination unit is
A heart sound frequency calculating unit that calculates the frequency of appearance of heart sounds by the heart sound band signal specified by the heart sound specifying unit at a plurality of heart rates for each type of heart sound;
The heart sound determination unit determines whether or not there is an abnormality in the detected heart sound signal by comparing the frequency for each heart sound type calculated by the heart sound frequency calculation unit with a predetermined threshold value for each heart sound type. .

  According to the heart sound measuring apparatus of this embodiment, the heart sound determination unit calculates, for each heart sound type, the frequency at which heart sounds based on heart sound band signals appear at the plurality of heart rates by the heart sound frequency calculation unit. The appearance frequency for each type is compared with a threshold value to determine whether there is an abnormality in the heart sound signal. Therefore, it is possible to reduce the influence of normal heart sound burying and misrecognition of excessive heart sounds caused by accidental noise from outside the living body other than the heart sound, and more accurately determine whether there is an abnormality in the heart sound signal. It becomes possible.

In the heart sound measuring device according to the embodiment, the heart noise determination unit may determine, for each type of heart noise, a frequency at which heart noise due to the heart noise band signal specified by the heart noise specifying unit appears in a plurality of heart rates. Further comprising a cardiac noise frequency calculation unit for calculating,
The cardiac noise determination unit compares the frequency of each type of cardiac noise calculated by the cardiac noise frequency calculation unit with a predetermined threshold value for each type of cardiac noise, thereby detecting an abnormality of the detected cardiac sound signal. Determine presence or absence.

  According to the heart sound measuring apparatus of this embodiment, the heart noise determination unit determines the frequency of occurrence of heart noise due to the specified heart noise band signal at the plurality of heart rates by the heart noise frequency calculation unit. It is calculated for each type, and the appearance frequency for each type of heart noise is compared with a threshold value to determine whether there is an abnormality in the heart sound signal. As a result, it is possible to reduce the influence of misrecognition of heart noise caused by accidental mixing of noise other than the sound of the heart from the outside of the living body, and more accurately determine whether there is an abnormality in the heart sound signal.

  According to the heart sound measuring apparatus of the present invention, the cardiac cycle time division unit calculates the division period of the cardiac cycle based on the pulse wave propagation time and the pulse wave signal determined by the pulse wave propagation time determination unit. Therefore, it is possible to accurately specify the cardiac cycle and its divided period in consideration of the pulse wave propagation time. Therefore, even when the peripheral part such as the wrist, finger, and ankle is used as the measurement part, which is relatively easy to mount the pulse wave detection part, the cardiac cycle time division part is not affected by the pulse wave propagation time. Thus, the cardiac cycle can be accurately identified. Therefore, the heart sound specifying unit can specify in which divided period of the plurality of divided periods of the accurately specified heart cycle the heart sound band signal is present, and accurately specify the type of heart sound based on the heart sound band signal. It becomes possible to identify.

  That is, according to the present invention, even when the cardiac cycle (systole / diastolic phase) is determined based on the pulse wave, the type of heart sound and heart noise can be identified without being affected by the pulse wave propagation time. As a result, a pulse wave that is easier to measure than electrocardiogram can be used as a signal to be measured simultaneously with the heart sound, so that ordinary people can easily check for the presence of excessive heart sounds and heart noise on a daily basis at home. It becomes possible.

It is a block diagram which shows one Embodiment of the heart sound measuring apparatus which concerns on this invention. It is a wave form diagram which shows an example of each division | segmentation period of the cardiac cycle by the waveform of a pulse wave signal, and a cardiac cycle time division part. It is a figure which shows an example of discrimination | determination of the heart sound and the heart noise in each division period of a cardiac cycle as a list. It is a flowchart which shows an example of operation | movement of the heart sound measuring apparatus of the said embodiment. It is a wave form diagram which shows an example of a normal heart sound signal. It is a wave form diagram showing an example of a heart sound signal when there is aortic valve stenosis. It is a wave form diagram showing an example of a heart sound signal when there is aortic valve insufficiency. It is a wave form diagram which shows an example of a heart sound signal in case there exist III sound and IV sound which are excess heart sounds. It is a figure which shows an example of the output of the determination result by the output part of the heart sound measuring apparatus of the said embodiment.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(Configuration of heart sound measuring device)
FIG. 1 is a block diagram of a heart sound measuring apparatus according to an embodiment of the present invention. The heart sound measuring device of this embodiment includes an analysis processing unit 1, a heart sound detection unit 2, a pulse wave detection unit 3, and an output unit 10.

  The heart sound detector 2 detects a sound generated from a human heart as a living body and outputs it as a heart sound signal. The heart sound detection unit 2 is attached to a predetermined part near the heart of the living body, collects sound generated from the heart of the living body, and outputs it as a heart sound signal. As a sound detection method by the heart sound detection unit 2, for example, an ultra-small microphone functioning as a heart sound sensor is fixed to the chest of the measurement subject with an adhesive tape or the like, and is provided inside the heart sound detection unit 2. Sound collected by a piezoelectric element (not shown) is converted into a weak electrical signal, and an analog electrical signal amplified by an amplifier (not shown) provided in the heart sound detector 2 is output as a heart sound signal. To do.

  Furthermore, an AD converter may be provided inside the heart sound detection unit 2 and output as a heart sound signal obtained by converting an electrical signal into digital data. Furthermore, if the heart sound detection unit 2 includes a battery and a wireless communication unit (not shown), and the heart sound signal converted into digital data is transmitted wirelessly by the wireless communication unit, the heart sound detection unit 2 is made wireless. It is possible to collect heart sound signals with low restraint and less trouble to daily life. In this case, the analysis processing unit 1 of this heart sound measuring device is also provided with a wireless communication unit (not shown) so that it can receive the digitally converted heart sound signal transmitted wirelessly from the heart sound detection unit 2. .

  The heart sound detection method by the heart sound detection unit 2 is not limited to the above, and various detection methods can be adopted as long as the sound generated from the heart of the living body to be measured can be collected. be able to.

  The pulse wave detection unit 3 is attached to a certain part of the human body as the living body (for example, a peripheral part such as a wrist, a finger, and an ankle), and a local pulse wave of an artery to be measured. Is detected and output as a pulse wave signal.

  As the pulse wave detection method by the pulse wave detector 3, for example, (a) the light receiving element detects the degree to which the measurement light emitted from the light emitting element is reflected or absorbed according to the blood volume in the artery. There are a photoelectric volume pulse wave method, and (b) a pressure pulse wave method in which a change in pressure in an artery is detected by a piezoelectric element or the like in close contact with a living body.

  The pulse wave detection method by the pulse wave detection unit 3 is not limited to the above (a) and (b), and any method can locally detect the pulse wave of the artery to be measured. For example, various known detection methods can be employed. The pulse wave measurement site is not particularly limited, but is preferably as minimally invasive and low-restraint as possible. , Fingertips, wrists, earlobe, ankles and the like.

  The pulse wave detection unit 3 can be made wireless by including a battery and a wireless communication unit (not shown) as in the case of the heart sound detection unit 2, but if the measurement site is a wrist, for example, If the analysis processing unit 1 forming the main body of the heart sound measuring device is a wristwatch type and the pulse wave detection unit 3 is integrally formed with the analysis processing unit 1, wireless connection is not necessary. If the measurement site is a fingertip, wireless connection is not necessarily required if the pulse wave detector 3 attached to the fingertip and the analysis processing unit 1 forming the wristwatch-type heart sound measuring device main body are connected with a short cable. Not there. In other words, an appropriate configuration may be adopted according to the usage form and purpose of the apparatus.

  The pulse wave signal output from the pulse wave detection unit 3 and the heart sound signal output from the heart sound detection unit 2 are input to the analysis processing unit 1.

  The analysis processing unit 1 includes a heart sound band extraction unit 4 and a heart noise band extraction unit 5. Only one of the heart sound band extraction unit 4 and the heart noise band extraction unit 5 may be provided. The heart sound band extraction unit 4 extracts a component corresponding to the frequency of the heart sound from the heart sound signal and outputs it as a heart sound band signal. Specifically, the heart sound band extraction unit 4 functions as a bandpass filter that transmits only a signal in a frequency band that is a main frequency component of the heart sound without attenuation. The transmission frequency band of this band-pass filter may be set to about 20 to 100 Hz as an example. However, since the frequency band of heart sounds varies depending on individual differences and physical condition, an optimal transmission frequency band is selected as necessary. It is desirable that it can be set.

  Further, the heart sound band extraction unit 4 is provided with a plurality of bandpass filters having different frequency bands in accordance with the type of heart sound to be detected, and extracts frequency components for each heart sound type to extract the heart sound for each heart sound type. A band signal may be output. For example, I sound (S1) and II sound (S2), which are normal heart sounds, are typically in the range of I sound (S1) in the range of 70 to 140 Hz and II sound (S2) in the range of 50 to 100 Hz. The III sound (S3) and the IV sound (S4), which are excessive heart sounds, typically have a III sound (S3) in the range of about 30 to 60 Hz and an IV sound (S4) in the range of about 20 to 50 Hz. Therefore, if the heart sound band extraction unit 4 is provided with a band pass filter for each type of I sound to IV sound of these heart sounds, and outputs a heart sound band signal for each heart sound type, the type of heart sound is determined. It becomes possible to specify more easily. For other harmonic heart sounds such as harmonic ejection sound (ES) and mitral valve opening sound (OS), a heart sound band signal can be extracted similarly by providing a band-pass filter for each type.

  When only the excessive heart sounds are measured, the band for the heart sound band extraction unit 4 is a band for III sound (S3), IV sound (S4), ejection sound (ES), and mitral valve opening sound (OS). Only a pass filter may be provided. That is, the heart sound band extraction unit 4 may be configured according to the type of heart sound to be measured.

  In addition, the band pass filter which comprises the heart sound zone extraction part 4 should just be implement | achieved by a digital filter process, when the heart sound signal output from the heart sound detection part 2 is digital data. When the heart sound signal output from the heart sound detection unit 2 is an analog electric signal, the bandpass filter constituting the heart sound band extraction unit 4 can be realized by an analog filter circuit. When the heart sound band extraction unit 4 is configured by this analog filter circuit, the heart sound band extraction unit 4 is not located inside the analysis processing unit 1 but between the analysis processing unit 1 and the heart sound detection unit 2.

  The cardiac noise band extracting unit 5 extracts a component corresponding to the frequency of cardiac noise from the cardiac sound signal and outputs it as a cardiac noise band signal. Specifically, the heart noise band extraction unit 5 functions as a bandpass filter that transmits only a signal in a frequency band that is a main frequency component of heart noise without attenuation. As an example, the transmission frequency band of the bandpass filter constituting the heart noise band extraction unit 5 may be set to about 100 to 500 Hz, but the frequency band of the heart noise is necessary because it varies depending on individual differences and physical condition. It is desirable that an optimal transmission frequency band can be set according to the frequency.

  Further, like the above-described heart sound band extraction unit 4, the heart noise band extraction unit 5 may include a plurality of band pass filters having different frequency bands according to the type of heart noise to be detected. The cardiac noise band extraction unit 5 composed of a plurality of bandpass filters having different frequency bands can extract a frequency component for each type of cardiac noise and output a cardiac noise band signal for each type of cardiac noise. .

  The band-pass filter constituting the heart noise band extraction unit 5 is realized by digital filter processing when the heart sound signal output from the heart sound detection unit 2 is digital data, as in the heart sound band extraction unit 4 described above. That's fine. When the heart sound signal output from the heart sound detection unit 2 is an analog electrical signal, the bandpass filter constituting the heart noise band extraction unit 5 can be realized by an analog filter circuit. In the case of this analog filter circuit, the heart noise band extracting unit 4 is located not between the analysis processing unit 1 but between the analysis processing unit 1 and the heart sound detection unit 2.

  Note that the heart sound band extraction unit 4 and the heart noise band extraction unit 5 described above do not necessarily need to include both. For example, when only the heart noise is measured, only the heart noise band extraction unit 5 may be provided. . When only the heart sound is measured, only the heart sound band extraction unit 4 may be provided.

  Further, the analysis processing unit 1 includes a pulse wave propagation time determination unit 11 that determines a pulse wave propagation time in which a pulse wave propagates from the aortic origin of the living body to the partial position. The pulse wave propagation time determination unit 11 propagates the pulse wave signal measured by the pulse wave detection unit 3 at the same time as the heart sound signal detected by the heart sound detection unit 2 from the aortic origin to the peripheral pulse wave measurement site. The pulse wave propagation time T, which is the time required to do this, is determined.

More specifically, the pulse wave propagation time determination unit 11 calculates the pulse wave velocity PWV from the pulse wave signal by analyzing the acquired pulse wave signal. Further, the pulse wave propagation time determination unit 11 calculates the pulse wave according to the following equation (1) based on the calculated pulse wave propagation speed PWV and the distance L from the aortic root to the peripheral pulse wave measurement site. The propagation time T is calculated.
T = L / PWV (1)

As a method of calculating the pulse wave velocity PWV from one pulse wave signal measured at one measurement site by the pulse wave detection unit 3, a traveling wave component and a reflected wave component included in the pulse wave are extracted, There is a method for calculating the pulse wave velocity from the time difference (phase difference) between the traveling wave component and the reflected wave component. Such a method for calculating the pulse wave velocity is disclosed in Japanese Patent Laid-Open Nos. 2003-10139 and 2007-7075. For example, the peak of the traveling wave component and the peak of the reflected wave component of the pulse wave detected by the pressure pulse wave detection probe are determined, and the time difference between the peak of the traveling wave component and the peak of the reflected wave component is defined as the pulse wave propagation time. The pulse wave propagation velocity is calculated from the pulse wave propagation time and the pulse wave propagation distance. As the pulse wave propagation distance, for example, a distance from the aortic valve to a pulse wave detection site through a reflection point located in the vicinity of the iliac artery is adopted. In addition, as a method for obtaining the distance L from the aortic origin to the peripheral pulse wave measurement site, the user previously measures the distance from the vicinity of the aortic origin to the peripheral pulse wave measurement site. Although a method of storing in a storage unit (not shown) built in the heart sound pulse measuring device is conceivable, the distance L may be determined by other methods.
The method for determining the pulse wave propagation time T is not limited to these methods. For example, the pulse wave propagation time T is measured by using a device that measures other pulse wave propagation speed (or pulse wave propagation time). Various methods can be employed, such as using the value of pulse wave velocity (or pulse wave propagation time) by taking it into a heart sound measuring device.

  In addition, the analysis processing unit 1 of this embodiment includes a cardiac cycle time division unit 6. The pulse wave propagation time T calculated by the pulse wave propagation time determining unit 11 is input to the cardiac cycle time division unit 6, and the cardiac cycle time division unit 6 receives the pulse wave propagation time T and the pulse wave. Based on the signal, a divided period obtained by dividing the cardiac cycle of the heart into a plurality of parts is defined.

  Specifically, the cardiac cycle time division unit 6 temporally outputs a pulse wave signal obtained from the pulse wave detection unit 3 as shown in the column (A) of FIG. 2 for a time corresponding to the pulse wave propagation time T. Analyzing the pulse wave signal going back to. The pulse wave signal traced back in time is shifted forward by the pulse wave propagation time T by the phase of the pulse wave signal in the column (A) of FIG. 2, as exemplified in the column (B) of FIG. Signal.

  The cardiac cycle time division unit 6 extracts a feature point related to a change in the cardiac cycle from the pulse wave signal shown in FIG. 2B that is traced back by this pulse wave propagation time T, and based on this feature point, A reference timing for time-dividing the cycle is generated.

  The cardiac cycle time division unit 6 extracts, for example, the phase of the minimum point A1 corresponding to the start of the systole of the cardiac cycle from the pulse wave signal shown in the column (B) of FIG. 2, and further expands the cardiac cycle. A phase of a notch (dichroic notch) B corresponding to the start of the period is extracted, and a minimum point A2 corresponding to the start of the systole of the next pulse (beat) is extracted. The cardiac cycle time division unit 6 determines the reference timings P1, P2, P3 indicating the systole Q1 and the diastole Q2 as shown in the column (C) of FIG. To decide.

  By doing so, the cardiac cycle is specified without being influenced by the pulse wave propagation time T even when using peripheral measurement sites such as wrists, fingers, and ankles, where the pulse wave detector 3 is relatively easy to wear. be able to.

  Here, as shown in the column (B) of FIG. 2, the pulse waveform minimum points A1 and A2 have a time delay TC with respect to the reference timings P1 and P3 of the start point of the systole Q1 of the heart sound signal, The notch B of the pulse waveform has a time delay TD with respect to the reference timing P2 at the start point of the diastole Q2 of the heart sound signal. The time delays TC and TD are due to a slight time difference until a change in blood output accompanying the contraction and dilation of the heart appears as a change in arterial pulsation. The time delays TC and TD vary depending on individual differences and physical condition. Therefore, in this embodiment, as shown in the (B) column and (C) column of FIG. 2, the time delay TC is subtracted from the time of the minimum points A1 and A2 of the pulse waveform (temporal). The reference timings P1 and P3 of the start point of the systole Q1 of the heart sound signal are determined. Further, in this embodiment, as shown in the (B) column and (C) column of FIG. 2, the time delay TD is subtracted from the time of the notch B of the pulse waveform (retrospectively in time). The reference timing P2 of the starting point of the expansion period Q2 is determined. In this embodiment, the time delay TC is a value obtained in advance, for example, and the time of the I sound (S1) corresponding to the start of the systole Q1 of the heart sound signal and the minimum points A1 and A2 of the pulse waveform. A value obtained by measuring data obtained by measuring a time difference Δt1 with respect to a plurality of subjects from a young person to an elderly person for each gender by a statistical method is used. In this embodiment, the time delay TD is a value obtained in advance, for example, and the time of the II sound (S2) corresponding to the start of the diastole Q2 of the heart sound signal and the notch B of the pulse waveform. A value obtained by measuring data obtained by measuring a time difference Δt2 with respect to a plurality of subjects from young to elderly for each gender by a statistical method is used.

  Further, the cardiac cycle time division unit 6 may further divide the cardiac cycle TH more finely. For example, the systolic period Q1 shown in the column (C) of FIG. 2 is divided into an early systolic period Q11, a middle systolic period Q12, and a late systolic period Q13 as shown in the column (D) of FIG. You may divide into Q21, expansion middle Q22, and expansion late Q23. In this case, the cardiac cycle time division unit 6 divides the cardiac cycle TH into six periods. Thereby, it is possible to specify the type of heart sound and heart noise more finely. The method for dividing the cardiac cycle is not particularly limited. For example, the systolic period Q1 and the diastolic period Q2 shown in the column (B) of FIG. 2 may be simply divided into n (n is a natural number of 2 or more), respectively, or the division timing may be determined by analyzing the pulse wave signal. May be determined. In addition, cardiac cycle such as determining the division timing based on the results obtained by statistical methods for data obtained by measuring multiple subjects from young to elderly for each gender as described above As long as the method can properly divide the data, various division methods can be employed.

  In addition, the analysis processing unit 1 of this embodiment includes a heart sound specifying unit 7. The heart sound specifying unit 7 has a heart sound band signal, which is a component extracted by the heart sound band extracting unit 4, of a plurality of divided periods Q 1, Q 2 or Q 11 -Q 13, Q 21 -Q 23 defined by the heart cycle time dividing unit 6. Which of the divided periods is specified, and the type of heart sound based on the heart sound band signal is specified.

  More specifically, the heart sound specifying unit 7 is provided for each divided period (Q1, Q2, Q11 to Q13, Q21 to Q23) defined by the cardiac cycle time dividing unit 6 time-dividing the cardiac cycle TH. Referring to the heart sound band signal in each divided period, it is determined whether or not there is a signal that meets a predetermined condition indicating the characteristics of the heart sound. Then, as a result of referring to the heart sound band signal during each of the divided periods, the heart sound specifying unit 7 determines that the heart sound band signal is a heart sound when there is a heart sound band signal satisfying a predetermined condition indicating the characteristics of the heart sound. Recognize and specify the type of heart sound based on the heart sound band signal. Here, examples of the predetermined condition indicating the characteristics of the heart sound include the amplitude value, the number of amplitudes, and the duration of the sound signal included in the heart sound band signal. Using these conditions, it is possible to easily determine whether or not the heart sound band signal satisfies the characteristics of heart sounds. By appropriately combining these conditions, for example, the amplitude value of the sound signal included in the heart sound band signal is greater than or equal to a predetermined magnitude, the number of amplitudes is within a predetermined range, and the duration is predetermined. If it is within the range, it is determined that a predetermined condition is satisfied. Note that the determination conditions for the heart sound are not limited to those described above. For example, various determinations can be made as long as the method can appropriately determine the presence of heart sounds during each divided period, such as using time-frequency analysis. The method can be adopted.

  When the heart sound band extraction unit 4 is configured to output a heart sound band signal for each type of heart sound, the heart sound specifying unit 7 determines each divided period (Q1, Each heart sound band signal for each type of heart sound in Q2, Q11 to Q13, Q21 to Q23) is referred to, respectively, to determine whether or not there is a signal that meets a predetermined condition indicating the characteristics of each heart sound. Then, the heart sound specifying unit 7, when there is a signal satisfying a condition indicating any one characteristic of each heart sound for each type of the heart sound band signal in each divided period, The type of heart sound can be identified. Thereby, for example, the discrimination between the subtone I sound (S1) and the harmonic ejection sound (ES) appearing in the early contraction period Q11 in the (D) column in FIG. 2 or the (D) column in the (D) column in FIG. More accurate classification of heart sounds that occur in the same period (within the same division period), such as discrimination between subtone II sounds (S2) and harmonic mitral valve opening sounds (OS) that appear in Q21 Can be identified.

  In addition, as described above, even when the heart sound band extraction unit 4 outputs only one type of heart sound band signal in a configuration that does not output a heart sound band signal for each type of heart sound, a plurality of types of heart sounds are selected for each divided period. It is possible to specify. That is, in this case, the heart sound specifying unit 7 sets a predetermined condition (such as the amplitude value of the heart sound band signal, the number of amplitudes, the duration, the frequency characteristics, etc.) indicating characteristics specific to each heart sound for one type of heart sound band signal. A plurality is used for each type. Thereby, it is possible to specify a plurality of types of heart sounds for each divided period from one type of heart sound band signal.

  In addition, the analysis processing unit 1 of this embodiment includes a cardiac noise specifying unit 8. The cardiac noise specifying unit 8 is configured such that a cardiac noise band signal, which is a component extracted by the cardiac noise band extracting unit 5, is converted into a plurality of divided periods Q1, Q2 or Q11 to Q13, Q21 defined by the cardiac cycle time dividing unit 6. The division period of -Q23 is specified, and the type of cardiac noise due to the cardiac noise band signal is specified.

  More specifically, the cardiac noise specifying unit 8 is divided into division periods (Q1, Q2, Q11 to Q13, Q21 to Q23) defined by the cardiac cycle time division unit 6 performing time division on the cardiac cycle TH. By referring to the heart noise band signal during each divided period, it is determined whether or not there is a signal that meets a predetermined condition indicating the characteristics of the heart noise. Then, as a result of referring to the cardiac noise band signal during each of the divided periods, the cardiac noise specifying unit 8, if there is a cardiac noise band signal that satisfies a predetermined condition indicating the characteristics of the cardiac noise, The band signal is recognized as heart noise, and the type of heart noise due to the heart noise band signal is specified. Here, examples of the predetermined condition indicating the characteristics of the cardiac noise include the amplitude value, the number of amplitudes, and the duration of a sound signal included in the cardiac noise band signal. Using these conditions, it is possible to easily determine whether or not the cardiac noise band signal satisfies the characteristics of cardiac noise. By appropriately combining these conditions, for example, the amplitude value of the sound signal included in the heart sound band signal is greater than or equal to a predetermined magnitude, the number of amplitudes is within a predetermined range, and the duration is predetermined. If it is within the range, it is determined that a predetermined condition is satisfied. Note that the determination condition of the above-mentioned heart noise is not limited to the above-described ones. For example, various methods can be used as long as the method can appropriately determine the presence of heart noise during each divided period, such as using time-frequency analysis. Can be adopted.

  When the cardiac noise band extracting unit 5 is configured to output a cardiac noise band signal for each type of cardiac noise, the cardiac noise specifying unit 8 includes each division defined by time-dividing the cardiac cycle TH. Whether there is a signal that meets a predetermined condition indicating characteristics of each heart noise by referring to each heart noise band signal for each type of heart noise during the period (Q1, Q2, Q11 to Q13, Q21 to Q23) Determine whether or not. Then, the cardiac noise specifying unit 8 has a type indicating the characteristics when there is a signal satisfying a condition indicating any characteristic of the cardiac noise for each type of the cardiac noise band signal in each of the divided periods. The type of heart murmur can be identified. This makes it possible to more accurately identify the type of cardiac noise that occurs in the same period (within the same divided period).

  Even when the cardiac noise band extracting unit 4 outputs only one type of cardiac noise band signal in a configuration that does not output a cardiac noise band signal for each type of cardiac noise, a plurality of types of cardiac noise are provided for each divided period. Can be specified. That is, in this case, the cardiac noise specifying unit 8 performs, for one type of cardiac noise band signal, a predetermined condition indicating a characteristic characteristic of each cardiac noise (amplitude value, number of amplitudes, duration, frequency characteristics of the cardiac noise band signal). It is also possible to identify a plurality of types of cardiac noise for each divided period from one type of cardiac noise band signal.

  Note that both the heart sound specifying unit 7 and the heart noise specifying unit 8 described above do not necessarily need to include both. For example, when only the heart noise is specified, only the heart noise specifying unit 8 may be provided. When only the heart sound is measured, only the heart sound specifying unit 7 may be provided.

  Further, the analysis processing unit 1 of this embodiment includes a determination unit 9 having a heart sound determination unit 15 and a heart noise determination unit 16.

  The heart sound determination unit 15 outputs, as determination result information, the result of determining the presence / absence of the detected heart sound signal and the type of abnormality based on the type of heart sound based on the heart sound band signal specified by the heart sound specifying unit 7 To do. In addition, the cardiac noise determination unit 16 determines the presence / absence of abnormality of the detected heart sound signal and the type of abnormality based on the type of cardiac noise based on the cardiac noise band signal identified by the cardiac noise identification unit 8. Is output as determination result information.

  More specifically, the heart sound determination unit 15 is divided into a plurality of divided periods by the heart sound specifying unit 7 for each of a plurality of divided periods (Q1, Q2, Q11 to Q13, Q21 to Q23) defined by the cardiac cycle time dividing unit 6. With reference to the presence or absence of the specified heart sound, it is determined whether or not an excessive heart sound has appeared and whether or not a normal heart sound has appeared in a predetermined divided period, and based on this determination result The presence or absence of abnormality of the detected heart sound signal and the type of abnormality are determined. That is, the heart sound determination unit 15 determines that the detected heart sound signal is abnormal when the excessive heart sound appears, and the heart sound based on the heart sound signal when the normal heart sound does not appear. Is determined to be abnormal. On the other hand, when the excessive heart sound does not appear and the normal heart sound appears, the heart sound determination unit 15 determines that the heart sound signal is not abnormal due to the excessive heart sound.

  In addition, the cardiac noise determination unit 16 performs the division by the cardiac noise identification unit 8 during each divided period for each of a plurality of divided periods (Q1, Q2, Q11 to Q13, Q21 to Q23) defined by the cardiac cycle time dividing unit 6. With reference to the presence or absence of the specified heart noise, it is determined whether or not heart noise has appeared. Based on the determination result, the presence or absence of the detected heart sound signal and the type of abnormality are determined. That is, when the cardiac noise has appeared, the cardiac noise determination unit 16 determines that the detected cardiac sound signal is abnormal due to cardiac noise, while when the cardiac noise has not appeared, It is determined that the heart sound signal is not abnormal due to heart noise.

  Next, an example of discrimination of heart sounds and heart noises in the cardiac cycle TH will be described with reference to the table shown in FIG. In the table of FIG. 3, as shown in the leftmost column, the cardiac cycle TH is time-divided into six divided periods, namely, the early systolic period Q11, the middle systolic period Q12, the late systolic period Q13, the early diastole Q21, the middle diastole Q22, and the late diastole Q23. An example is shown.

  In this example, a heart sound column is provided in the center column of the above table, and a heart noise column is provided in the right end column. In the heart sound column, a normal heart sound column and an excessive heart sound column are provided. In the normal heart sound column, the normal heart sound I sound (S1) appears in the early contraction period Q11, and the normal heart sound II sound ( S2) is shown to appear in Q21 in the first half of the expansion. In the excessive heart sound column, ejection sound (ES) appears in the early contraction Q11, mitral valve opening sound (OS) appears in the expanded early Q21, and the III sound (S3) appears in the expanded early Q21. It is shown that the IV sound (S4) appears in the late expansion Q23, appearing over either one or both of the expansion middle Q22. In the heart noise column, total systolic reflux noise appears in the early systolic period Q11, systolic ejection noise appears from the early systolic period Q11 to the middle systolic period Q12, and extended early reflux noise appears. It is shown that the middle diastole rambling noise appears in the early diastole Q21, the mid diastole rambling noise appears in the mid diastole Q22, and the atrial contraction noise appears in the late diastole Q23.

  In this way, in the cardiac cycle (leftmost column) in FIG. 3, in each divided period Q11 to Q13, Q21 to Q23 of the cardiac cycle, the column of “normal heart sounds” should appear if it is normal (I sound). , II sound). The heart sound determination unit 15 produces an I sound in the first contraction Q11, an II sound in the first expansion Q21, and an excessive heart sound over each of the divided periods Q11 to Q13, Q21 to Q23 of the cardiac cycle. Otherwise, it is determined that the detected heart sound signal is not abnormal due to excessive heart sounds. In addition, the heart sound determination unit 15 abnormally detects heart sounds in each case in which no I sound appears in the first contraction period Q11, II sound does not appear in the first expansion period Q21, or the excessive heart sound appears in the cardiac cycle. Judge that there is.

  The cardiac noise determination unit 16 determines that the detected cardiac sound signal is free of abnormality due to cardiac noise if the cardiac noise does not appear in any of the divided periods Q11 to Q13 and Q21 to Q23 in FIG. When the cardiac noise appears in any of the divided periods of the cardiac cycle, it is determined that the cardiac sound signal is abnormal due to cardiac noise.

  The determination unit 9 is not limited to the determination example described with reference to FIG. 3 described above. For example, a heart sound other than the I sound (S1) in the first contraction period Q11 and the II sound (S2) in the first expansion period Q21, If heart murmur is specified, it may be determined as abnormal. Further, the determination unit 9 determines whether cardiac noise is present in the systolic noise by determining whether the cardiac noise is present in the systole or diastole in the cardiac cycle TH. It is good also as what discriminate | determines which is two types of cardiac noise of a diastolic noise. As the determination unit 9, any other determination method may be adopted as long as it can determine at least whether there is an abnormality in heart sound or heart noise. In addition, both the heart sound determination unit 15 and the heart noise determination unit 16 described above do not necessarily need to include both. For example, when only the heart noise is determined, only the heart noise determination unit 16 may be included. When only the heart sound is determined, only the heart sound determination unit 15 may be provided.

  In this embodiment, the heart sound determination unit 15 may include a heart sound frequency calculation unit 17. The heart sound frequency calculating unit 17 calculates the frequency at which heart sounds based on the heart sound band signal specified by the heart sound specifying unit 7 appear in a plurality of heart rates for each type of heart sound. In this case, the heart sound determination unit 15 compares the frequency for each heart sound type calculated by the heart sound frequency calculation unit 17 with a predetermined threshold value for each heart sound type, thereby detecting an abnormality in the detected heart sound signal. The presence or absence of is determined.

Specifically, the heart sound frequency calculation unit 17 calculates the frequency of appearance of excess heart sounds and normal heart sounds for each divided period of each heart cycle for a preset heart rate, and the heart sound determination unit 15 calculates the calculated excess sound amount. The presence / absence of abnormality is determined by comparing the appearance frequency of the heart sound and the normal heart sound with a preset threshold value. For example, when the threshold value of the appearance frequency of normal heart sounds is set to 90% and the threshold value of the appearance frequency of excessive heart sounds is set to 30% as the threshold value, the heart sound determination unit 15 sets the appearance frequency of the normal heart sounds to 90%. If it is less than 30% or the frequency of excess heart sounds is 30% or more, it is determined as “abnormal”, and in other cases (that is, the frequency of normal heart sounds is 90% or more and the frequency of excess heart sounds is less than 30%) Is determined to be “normal”. An appropriate value may be arbitrarily set as the threshold value, but it is desirable that an optimum threshold value can be set as necessary in consideration of individual differences, changes due to physical condition, measurement errors, and the like.
Note that the determination result information output by the heart sound determination unit 15 is information that can identify at least the presence or absence of an abnormality in the heart sound signal. If there is an abnormality due to excessive heart sounds, the determination result information is further specified as information for identifying the cause of the abnormality. It is desirable to include information indicating the type of excessive heart sounds that have been made. Furthermore, when the heart sound determination unit 15 includes the heart sound frequency calculation unit 17, it is preferable that the determination result information includes information indicating the appearance frequency of excessive heart sounds.

  In this embodiment, the cardiac noise determination unit 16 may include a cardiac noise frequency calculation unit 18. The cardiac noise frequency calculation unit 18 calculates the frequency at which cardiac noise due to the cardiac noise band signal identified by the cardiac noise identifying unit 8 appears in a plurality of heart rates for each type of cardiac noise. In this case, the cardiac noise determination unit 16 detects the frequency of each type of cardiac noise calculated by the cardiac noise frequency calculation unit 18 by comparing the frequency with a predetermined threshold value for each type of cardiac noise. Determine whether there is an abnormality in the heart sound signal. For example, when the threshold value of the appearance frequency of a certain type of cardiac noise is set to 30% as the threshold value, the cardiac noise determination unit 16 determines that “abnormal” if the frequency of occurrence of the cardiac noise is 30% or more. In other cases (ie, the occurrence frequency of heart noise is less than 30%), it is determined as “normal”. An appropriate value may be arbitrarily set as the threshold value, but it is desirable that an optimum threshold value can be set as necessary in consideration of individual differences, changes due to physical condition, measurement errors, and the like.

  The determination result information output from the cardiac noise determination unit 16 is information that can identify at least the presence or absence of abnormality due to cardiac noise. If there is an abnormality due to cardiac noise, the determination result information is further used as information for identifying the cause of the abnormality. It is desirable to include information indicating the specified type of cardiac noise. Furthermore, when the cardiac noise determination unit 16 includes the cardiac noise frequency calculation unit 18, the determination result information preferably includes information indicating the appearance frequency of cardiac noise.

Further, the heart sound measuring device of this embodiment includes an output unit 10, and this output unit 10 includes a heart sound determination result output unit 20 and a heart noise determination result output unit 21. The heart sound determination result output unit 20 presents (or provides as data) determination result information of the heart sound signal output from the heart sound determination unit 15 to the user. The cardiac noise determination result output unit 21 presents (or provides as data) determination result information of the heart sound signal output from the cardiac noise determination unit 16 to the user. Moreover, presentation of the determination result information to the user by the output unit 10 is performed on various displays, for example.
The output unit 10 may be used for the purpose of using the heart sound measuring device, such as a display such as an LCD (liquid crystal display), a recording medium such as a memory card, and a communication interface that transmits data to an external device. Accordingly, it can be realized by appropriate output means. Moreover, if the waveform (heart sound diagram) of the heart sound signal is also presented simultaneously by the output unit 10, it is useful for the user to grasp the state of the heart sound. Further, the output unit 10 may simultaneously present the waveform of the pulse wave signal as necessary.
In addition, when the determination unit 9 includes the heart sound frequency calculation unit 17 and the heart noise frequency calculation unit 18, it is useful for the user if the output unit 10 also presents the frequency of occurrence of heart sounds and heart noises at the same time. is there. In this case, the waveform of the heart sound signal is generated by synthesizing the detected heart sound and heart noise from the heart sound signal for a predetermined heart rate and presented as a representative waveform, or the heart sound signal for the predetermined heart rate is generated. If an averaged waveform is generated and presented as a representative waveform, it becomes easier for the user to grasp the appearance of heart sounds and heart noise.

  The analysis processing unit 1 includes a microcomputer including a CPU, a ROM and a RAM (not shown), and an AD converter (not shown) if necessary. The CPU executes signal processing and analysis processing of the heart sound signal and the pulse wave signal using the AD converter, the RAM which is a temporary storage unit, or the like by a program stored in the ROM in advance, and the result is obtained. This is output to the output unit 10. Therefore, the analysis processing unit 1 uses the CPU to perform the heart sound band extraction unit 4, the heart noise band extraction unit 5, the pulse wave propagation time determination unit 11, the heart cycle time division unit 6, the heart sound identification unit 7, the heart noise identification. The functions of the unit 8, the heart sound determination unit 15, the heart noise determination unit 16, the heart sound frequency calculation unit 17, and the heart noise frequency calculation unit 18 are realized.

  Next, the operation of the heart sound measuring device of this embodiment will be described with reference to FIGS.

  FIG. 4 is a flowchart showing the operation of the heart sound measuring device. First, in step S101, the heart sound detection unit 2 and the pulse wave detection unit 3 simultaneously measure a heart sound signal and a pulse wave signal for a set time set in advance, and a RAM (not shown) provided in the analysis processing unit 1. ) Is stored sequentially. The set time may be arbitrarily set to an appropriate time corresponding to a predetermined heart rate of at least one heartbeat, but considering the influence of body movement, external noise, etc., measure about 30 heartbeats if possible. Is desirable. In this case, for example, assuming that the heart rate is 60 times / minute, the set time may be 30 seconds corresponding to 30 heartbeats.

  Subsequently, in step S102, the heart sound band extraction unit 4 and the heart noise band extraction unit 5 extract the heart sound band signal and the heart noise band signal from the heart sound signal, and as a signal time-sequentially associated with the heart sound signal, The data is sequentially stored in the RAM (not shown) provided in the analysis processing unit 1. When the heart sound signal output from the heart sound detection unit 2 is digital data, the heart sound signal stored in the RAM of the analysis processing unit 1 is digital-filtered in step S101 to perform the heart sound band signal and the heart noise band. Extract the signal. If the heart sound signal output from the heart sound detector 2 is an analog electrical signal, the heart sound band signal and the heart noise band signal are extracted by passing the heart sound signal measured in step S101 through an analog filter circuit. To do.

  Subsequently, in step S103, the pulse wave propagation time determining unit 11 included in the heart sound measuring device calculates a pulse wave propagation time T for each heartbeat (pulse) from the measured pulse wave signal, and the analysis processing unit 1 It memorize | stores in RAM (not shown) with which it is equipped. Subsequently, in step S104, the cardiac cycle time division unit 6 time-divides the cardiac cycle TH for each heartbeat to divide each division period (systolic Q1, diastolic Q2 and pre-systolic, middle, Late Q11 to Q13, pre-expansion, middle, late Q22 to Q23) are generated and stored in the RAM of the analysis processing unit 1 as timing information associated with heart sound signals in time series.

  Subsequently, in step S105, the heart sound specifying unit 7 and the heart noise specifying unit 8 specify heart sound and heart noise for each of the divided periods from the heart sound band signal and the heart noise band signal, and for each divided period. As time-related information, the information is stored in the RAM of the analysis processing unit 1. Subsequently, in step S <b> 106, the determination unit 9 determines the presence / absence of abnormality from the measured heart sound signals for the set time, and outputs the result to the output unit 10.

  By performing the above series of operations, the type of heart sound and heart noise included in the heart sound signal is specified based on the heart cycle specified by the pulse wave signal measured together with the heart sound signal, and abnormalities are detected from the specified heart sound and heart noise. Can be determined and presented to the user.

  Next, an example of measurement by the heart sound measuring device will be described with reference to FIGS. 5 to 8 are signal waveform diagrams showing one measurement example of heart sound signals having different characteristics. FIG. 9 shows an example of output of the determination result by the determination unit 9 corresponding to the heart sound signals in the measurement examples of FIGS. 5 to 8 to the output unit 10 (example of screen display on the display).

  5 to 8, the pulse wave signal output from the pulse wave detection unit 3 is a pulse wave signal that is traced back by a time corresponding to the pulse wave propagation time T in the (A) column. The signal waveform is shown. From this pulse wave signal, the cardiac cycle time division unit 6 specifies the divided periods (pre-systolic Q11 to late diastole Q23) divided into six that form the cardiac cycle of the heart. Moreover, the (B) column of each waveform diagram of FIG. 5 to FIG. 8 shows the signal waveform of the heart sound signal output from the heart sound detector 2. Further, in the (C) column of each of the waveform diagrams of FIGS. 5 to 8, the signal of the heart sound band signal output by extracting the frequency component of the heart sound from the heart sound signal of the column (B) by the heart sound band extracting unit 4. The waveform is shown. 5 to 8, the heart noise band signal output by extracting the frequency component of heart noise from the heart sound signal in the column (B) by the heart noise band extracting unit 5 is displayed in the column (D). The signal waveform is shown.

  FIG. 5B shows an example of a normal heart sound signal. Since the heart sound signal in the (B) column of FIG. 5 is normal, the heart sound band signal in the (C) column of FIG. 5 includes the I sound (S1) in the first contraction Q11 and the II sound (S2) in the first expansion Q21. Has appeared, and nothing appears as the cardiac noise band signal in the column (D) of FIG. In this case, as shown in the column (A) of FIG. 9, the display display as an example of the output unit 10 shows the waveform of the heart sound signal and the determination result by the determination unit 9 in the “determination” column at the bottom of the screen. "No error" is output.

  On the other hand, the (B) column of FIG. 6 is a waveform diagram of a heart sound signal showing an example when there is aortic valve stenosis. In this waveform diagram, in the heart sound signal in the column (B) of FIG. 6, in addition to the normal sounds I (S1) and II (S2), systolic noise appears at the peak of the systolic period Q12. . Accordingly, in the heart sound band signal in the column (C) of FIG. 6, the I sound (S1) appears in the early contraction Q11 and the II sound (S2) appears in the expansion early Q21, and the heart sound in the (D) column of FIG. In the noise band signal, cardiac noise (systolic ejection noise) mainly having the middle systolic period Q12 appears (appears at a frequency of 90% as an example). In this case, the display display as an example of the output unit 10 shows the waveform of the heart sound signal as shown in the column (B) of FIG. 9 and the heart noise frequency calculation unit 18 in the “determination” column at the bottom of the screen. “There is systolic noise (frequency: 90%)” is output as a determination result by the determination unit 9 provided.

  Moreover, the (B) column of FIG. 7 is a waveform diagram showing an example of a heart sound signal when there is aortic valve insufficiency. In this waveform diagram, in the heart sound signal in the column (B) of FIG. 7, in addition to the normal heart sounds I sound (S1) and II sound (S2), diastole noise appears at the peak of the early diastole Q21. . Accordingly, in the heart sound band signal in the column (C) of FIG. 7, the I sound (S1) appears in the early contraction Q11 and the II sound (S2) appears in the expansion early Q21, and the heart noise band in the column (D) of FIG. In the waveform diagram of the signal, cardiac noise (extended early reflux noise) mainly consisting of the extended first term Q21 appears (appears at a frequency of 80% as an example). In this case, as shown in the column (C) of FIG. 9, the display display as an example of the output unit 10 shows the waveform of the heart sound signal, and in the “determination” column at the bottom of the screen, the heart noise frequency calculation unit 18. “There is diastole noise (frequency: 80%)” is output as a determination result by the determination unit 9 including

  Moreover, the (B) column of FIG. 8 is a waveform diagram showing an example of a heart sound signal when there is an III sound (S3) and an IV sound (S4) which are excessive heart sounds. In this waveform diagram, in the heart sound signal in the column (B) of FIG. 8, in addition to the normal sounds I (S1) and II (S2), the excessive sounds III (S3) and IV (S4) ) Has appeared. Further, in the heart sound band signal in the column (C) of FIG. 8, in addition to the I sound (S1) appearing in the early contraction Q11 and the II sound (S2) appearing in the early expansion Q21, the III sound ( S3), the IV sound (S4) appears in the late expansion Q23 (for example, the III sound appears at a frequency of 40% and the IV sound appears at a frequency of 30%). Note that nothing appears as a cardiac noise band signal in the column (D) of FIG. In the case of the waveform diagram of FIG. 8, the display display as an example of the output unit 10 shows the waveform of the heart sound signal as shown in the (D) column of FIG. As the determination result by the determination unit 9 including the heart sound frequency calculation unit 17, “III sound present (frequency: 40%)” and “IV sound present (frequency: 30%)” are output.

  The heart sound measuring device of the present invention is suitable for use in evaluating excess heart sounds and heart noise, and is measured at a peripheral part that is easier to measure than the electrocardiogram for determining the cardiac cycle for identifying heart sounds and heart noise. Because it uses pulse waves, it can be used as a device that allows ordinary people to easily check for the presence of excessive heart sounds and heart noise on a daily basis at home, in addition to diagnostic heart sound measuring devices used in hospitals, etc. It is.

DESCRIPTION OF SYMBOLS 1 Analysis processing part 2 Heart sound detection part 3 Pulse wave detection part 4 Heart sound band extraction part 5 Heart noise band extraction part 6 Heart cycle time division part 7 Heart sound specific part 8 Heart noise specific part 9 Judgment part 10 Output part 11 Pulse wave propagation time Determination unit 15 Heart sound determination unit 16 Heart noise determination unit 17 Heart sound frequency calculation unit 18 Heart noise frequency calculation unit 20 Heart sound determination result output unit 21 Heart noise determination result output unit

Claims (8)

A heart sound detection unit that detects a sound generated from the heart of a living body and outputs it as a heart sound signal;
A heart sound band extraction unit that extracts and outputs a component corresponding to the frequency of the heart sound from the heart sound signal;
A pulse wave detector for detecting a pulse wave of a certain part of the living body and outputting it as a pulse wave signal;
A pulse wave propagation time determining unit for determining a pulse wave propagation time for the pulse wave to propagate from the aorta starting part of the living body to the partial position;
Based on the pulse wave propagation time determined by the pulse wave propagation time determination unit and the pulse wave signal, a cardiac cycle time division unit that defines a division period in which the cardiac cycle of the heart is divided into a plurality of times;
The heart sound band signal, which is a component extracted by the heart sound band extraction unit, is identified as being in any one of a plurality of divided periods defined by the heart cycle time division unit, and the heart sound based on the heart sound band signal A heart sound measuring device comprising: a heart sound specifying unit for specifying the type of the sound. The heart sound measuring device according to claim 1,
A cardiac noise band extracting unit that extracts and outputs a component corresponding to the frequency of cardiac noise from the cardiac sound signal;
The cardiac noise band signal, which is a component extracted by the cardiac noise band extraction unit, is specified in which of the plurality of divided periods defined by the cardiac cycle time division unit, and the cardiac noise band A heart sound measuring apparatus comprising: a heart noise specifying unit that specifies a type of heart noise caused by a signal. A heart sound detection unit that detects a sound generated from the heart of a living body and outputs it as a heart sound signal;
A cardiac noise band extracting unit that extracts and outputs a component corresponding to the frequency of cardiac noise from the cardiac sound signal;
A pulse wave detector for detecting a pulse wave of a certain part of the living body and outputting it as a pulse wave signal;
A pulse wave propagation time determining unit for determining a pulse wave propagation time for the pulse wave to propagate from the aorta starting part of the living body to the partial position;
Based on the pulse wave propagation time determined by the pulse wave propagation time determination unit and the pulse wave signal, a cardiac cycle time division unit that defines a division period in which the cardiac cycle of the heart is divided into a plurality of times;
The cardiac noise band signal, which is a component extracted by the cardiac noise band extraction unit, is specified in which of the plurality of divided periods defined by the cardiac cycle time division unit, and the cardiac noise band A heart sound measuring apparatus comprising: a heart noise specifying unit that specifies a type of heart noise caused by a signal. The heart sound measuring device according to claim 1 or 2,
A heart sound determination unit that outputs, as determination result information, a result of determining the presence or absence of abnormality of the detected heart sound signal, based on the type of heart sound by the heart sound band signal specified by the heart sound specifying unit;
A heart sound measurement device comprising: a heart sound determination result output unit for presenting the determination result information to a user. In the heart sound measuring device according to any one of claims 2 to 4,
Based on the presence or absence of cardiac noise due to the cardiac noise band signal identified by the cardiac noise identification unit, a cardiac noise determination unit that outputs the result of determining the presence or absence of a detected cardiac sound signal as determination result information;
A heart sound measurement apparatus comprising: a heart noise determination result output unit for presenting the determination result information to a user. The heart sound measuring device according to claim 5,
The cardiac murmur determination unit is
Results of determining the presence or absence of detected heart sound signal and the type of abnormality of the heart sound signal based on the presence or absence of heart noise due to the heart noise band signal specified by the heart noise specifying unit and the type of heart noise Is output as determination result information. In the heart sound measuring device according to any one of claims 4 to 6,
The heart sound determination unit
A heart sound frequency calculating unit that calculates the frequency at which heart sounds from the heart sound band signal specified by the heart sound specifying unit appear in a plurality of heart rates for each type of heart sound;
The heart sound determination unit determines whether or not there is an abnormality in the detected heart sound signal by comparing the frequency for each heart sound type calculated by the heart sound frequency calculation unit with a predetermined threshold value for each heart sound type. A heart sound measuring device characterized by the above. The heart sound measuring device according to any one of claims 5 to 7,
The cardiac murmur determination unit is
A heart noise frequency calculating unit that calculates the frequency at which heart noise due to the heart noise band signal specified by the heart noise specifying unit appears in a plurality of heart rates for each type of heart noise;
The cardiac noise determination unit compares the frequency of each type of cardiac noise calculated by the cardiac noise frequency calculation unit with a predetermined threshold value for each type of cardiac noise, thereby detecting an abnormality of the detected cardiac sound signal. A heart sound measuring device characterized by determining presence or absence.

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