Heart disease testing equipment

Abstract

To provide a heart disease examination device that can determine aortic valve stenosis and mitral valve insufficiency by a simple configuration, and provide a heart disease examination method.SOLUTION: A heart disease examination device has a phonocardiogram acquisition unit for acquiring a phonocardiogram of a subject, a systolic murmur measurement unit for measuring noise of late systolic among systolic murmurs of the phonocardiogram, and a determination unit for determining whether the subject is aortic valve stenosis or mitral valve insufficiency on the basis of the noise of the late systolic.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cardiac disease examination apparatus and a cardiac disease examination method that can distinguish between aortic valve stenosis and mitral valve regurgitation. [Background technology]

[0002] Aortic valve stenosis (AS) is a disease in which the aortic valve, one of the four valves in the heart that is located between the left ventricle and the aorta, becomes difficult to open due to inflammation and hardening. The number of AS patients is on the rise due to the aging population.

[0003] Mitral insufficiency (MI), also known as mitral regurgitation (MR), is a condition in which the mitral valve does not close properly during systole, allowing some blood to flow back into the left atrium as the left ventricle contracts.

[0004] Naturally, it is desirable to detect and treat aortic stenosis and mitral regurgitation early.

[0005] Generally, doctors diagnose aortic stenosis and mitral regurgitation based on the patient's phonocardiogram and electrocardiogram. However, accurate cardiac auscultation requires experience.

[0006] On the other hand, for example, Patent Document 1 discloses a diagnostic device that diagnoses heart valve disease by frequency analysis of a phonocardiogram. It is believed that use of such a diagnostic device would enable the diagnosis of heart valve disease even without a doctor with extensive experience in auscultation of heart sounds. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2007-508899 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the diagnostic device disclosed in Patent Document 1 requires vector and matrix calculations in a multidimensional space across all heart sounds, which increases the scale of calculations and results in a complex configuration. While a method of frequency analysis of a phonocardiogram using a wavelet transform is also conceivable, this method also has the drawback of increasing the scale of calculations.

[0009] The present invention has been made in consideration of the above points, and provides a heart disease examination device and a heart disease examination method that are capable of distinguishing between aortic valve stenosis and mitral valve regurgitation with a simple configuration. [Means for solving the problem]

[0010] One aspect of the cardiac disease examination device of the present invention is a phonocardiogram acquisition unit for acquiring a phonocardiogram of the subject; a systolic noise measuring unit that measures late systolic noise among systolic noises of the phonocardiogram; a determination unit that determines whether the subject has aortic stenosis or mitral regurgitation based on the late systolic murmur; Equipped with.

[0011] One embodiment of the cardiac disease examination method of the present invention comprises: obtaining a phonocardiogram of the subject; measuring late systolic murmurs from the phonocardiogram; determining whether the subject has aortic stenosis or mitral regurgitation based on the late systolic murmur; Includes. [Effects of the Invention]

[0012] According to the present invention, it is possible to distinguish between aortic stenosis and mitral regurgitation with a simple configuration. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a blood pressure pulse wave inspection device according to an embodiment. [Figure 2] A block diagram showing the main configuration of a cardiac disease examination device according to an embodiment. [Figure 3] Diagram explaining systolic murmur [Figure 4] 1 is a waveform diagram illustrating the operation of an embodiment of the present invention; [Figure 5] 5A and 5B are diagrams showing examples of systolic murmurs, in which FIG. 5A shows a systolic murmur in a case where the patient is not suffering from aortic stenosis or mitral regurgitation, FIG. 5B shows a systolic murmur caused by aortic stenosis, and FIG. 5C shows a systolic murmur caused by mitral regurgitation. [Figure 6] 1 is a flowchart illustrating a cardiac disease examination method performed by an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015] <1> Overall configuration of blood pressure pulse wave inspection device FIG. 1 is a diagram showing the overall configuration of a blood pressure pulse wave examination device 1 to which the cardiac disease examination device and cardiac disease examination method of the present invention are applied.

[0016] In FIG. 1, the main body 1a of the blood pressure pulse wave inspection device 1 is provided with an arithmetic processing unit 10, an input unit 70, a display unit 80, a printing unit 91, a memory unit 92, an audio output unit 93, a blood pressure pulse wave measuring unit 30, a heart sound measuring unit 40, an electrocardiogram measuring unit 50, and a pulse wave measuring unit 60.

[0017] The blood pressure pulse wave measurement unit 30 has an upper arm measurement control unit 31 and a lower limb measurement control unit 32. A right upper arm cuff 21R and a left upper arm cuff 21L are connected to the upper arm measurement control unit 31 via hoses 21h, and a right ankle cuff 22R and a left ankle cuff 22L are connected to the lower limb measurement control unit 32 via hoses 22h.

[0018] A heart sound microphone 23 is connected to the heart sound measurement unit 40. A four limb electrocardiogram electrode unit 24a and a chest electrocardiogram electrode unit 24b are connected to the electrocardiogram measurement unit 50. Amorphous pulse wave sensors 25a and 25b are connected to the pulse wave measurement unit 60.

[0019] The arithmetic processing unit 10 is a computer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), various interfaces, etc. The arithmetic control unit 10 executes a control program stored in the ROM with the CPU, thereby performing arithmetic processing for determining heart disease, which will be described below. In other words, the arithmetic control unit 10 has the function of determining heart disease.

[0020] In addition, the calculation processing unit 10 controls the upper arm measurement control unit 31, the lower limb measurement control unit 32, the heart sound measurement unit 40, the electrocardiogram measurement unit 50, and the pulse wave measurement unit 60 (hereinafter referred to as "each biological information measurement unit"), which measure various types of biological information.

[0021] The arithmetic processing unit 10 also receives biological information supplied from each biological information measurement unit. When the received biological information needs to be displayed on a screen, it edits or converts it into display data and outputs it to the display unit 80, and when it needs to be printed on a report form, it edits or converts it into print data and outputs it to the printing unit 91. The arithmetic processing unit 10 also stores the received biological information in the storage unit 92 and reads out the stored biological information as appropriate.

[0022] The calculation processing unit 10 also performs waveform analysis of the biological information received from each biological information measurement unit. In the waveform analysis, characteristic parts (dividing points) in the waveform are detected. Examples of characteristic parts include the start of the second heart sound, the rising edge of the pulse wave at the upper arm, the rising edge of the pulse wave at the ankle, and the notch of the pulse wave at the upper arm.

[0023] The arithmetic processing unit 10 calculates the degree of arteriosclerosis based on the analysis result and the value (for example, blood pressure) indicated by the received biological information.

[0024] In addition, the calculation processing unit 10 receives inputs and instructions from the input unit 70 through user operations, and in accordance with the received contents, performs settings related to the functions of each biometric information measurement unit, display unit 80, printing unit 91, memory unit 92 and audio output unit 93, and controls the start and stop of each operation.

[0025] The display unit 80 is a display device having a display screen such as an LCD (Liquid Crystal Display), and displays on the screen the biological information, analysis results, arteriosclerosis degree, etc. input from the arithmetic processing unit 10 as display data.

[0026] The printing unit 91 has as its main components a paper feed mechanism, a printing head, etc., and prints on paper the biological information, analysis results, and arteriosclerosis degree input as printing data from the arithmetic processing unit 10.

[0027] The storage unit 92 is configured with a hard disk drive, a writable optical disk drive, a nonvolatile memory, etc., and is capable of storing information from the calculation processing unit 10. The storage unit 92 also records biological information measured by each biological information measurement unit, that is, an electrocardiogram, a pulse wave, and heart sounds.

[0028] The audio output unit 93 has a speaker or the like as a main component, and outputs a guidance voice, an alert sound, or the like in accordance with the guidance data or an alert sound output instruction signal input from the calculation processing unit 10.

[0029] The input unit 70 is composed of a keyboard, a mouse, buttons, a touch panel, etc., and receives inputs and instructions from the user's operations and sends them to the arithmetic processing unit 10.

[0030] Pulse wave measuring unit 60 supplies the subject's pulse wave signals detected by amorphous pulse wave sensors 25a, 25b appropriately attached to the subject to calculation processing unit 10. This allows measurement and analysis of the pulse wave. Note that one of amorphous pulse wave sensors 25a, 25b is attached, for example, to the subject's carotid artery, and the other is attached, for example, to the subject's femoral artery or knee.

[0031] In this embodiment, the blood pressure pulse wave measuring unit 30 is configured by providing an upper limb measurement control unit 31 and a lower limb measurement control unit 32 independently, but the upper limb measurement control unit 31 and the lower limb measurement control unit 32 may be integrated together. Known technology may be used to measure blood pressure pulse waves using the blood pressure pulse wave measuring unit 30 having the upper limb measurement control unit 31 and the lower limb measurement control unit 32, so detailed description thereof will be omitted here.

[0032] The electrocardiogram measurement unit 50 supplies electrocardiogram signals detected by the four limb electrocardiogram electrodes 24a and the chest electrocardiogram electrodes 24b attached to the subject to the arithmetic processing unit 10. This allows electrocardiogram measurement and analysis. The four limb electrocardiogram electrodes 24a typically consist of four electrocardiogram electrodes attached to the right wrist, left wrist, right ankle, and left ankle, respectively. The electrocardiogram electrodes for both ankles are preferably configured so that their attachment to both ankles is not obstructed by the right ankle cuff 22R and the left ankle cuff 22L. The chest electrocardiogram electrode unit 25b typically consists of six electrocardiogram electrodes attached to six locations on the chest.

[0033] The heart sound measurement unit 40 supplies a heart sound signal detected by the heart sound microphone 23 attached to the subject to the calculation processing unit 10. In this way, the heart sounds are measured and analyzed.

[0034] <2> Determining heart disease according to this embodiment As described above, the arithmetic processing unit 10 of this embodiment has the function of diagnosing cardiac disease. In practice, it has the configuration shown in Fig. 2, and diagnosing cardiac disease is performed using this configuration. The arithmetic processing unit 10 has a systolic noise measurement unit 11, a measurement interval setting unit 12, and a determination unit 13.

[0035] The systolic noise measuring unit 11 measures late systolic noise from the systolic noise of the phonocardiogram. The measurement interval setting unit 12 sets a late systolic interval based on the electrocardiogram and outputs information about the set interval to the systolic noise measuring unit 11. The determining unit 13 determines whether the subject has aortic stenosis or mitral regurgitation based on the late systolic noise determined by the systolic noise measuring unit 11.

[0036] FIG. 3 is a diagram used to explain systolic murmurs. FIG. 3 shows an electrocardiogram, heart sounds, and heart murmurs. The peak of the R wave in the electrocardiogram and the start of the first heart sound are approximately the same, and the end of the T wave in the electrocardiogram and the start of the second heart sound are approximately the same. The systole (ventricular systole) can be said to be the period from the peak of the R wave to the end of the T wave, or the period from the end of the first sound to the start of the second sound. The systolic murmur is a noise contained in the heart sounds during the systole (ventricular systole). In other words, the systolic murmur is the heart sounds during the systole (ventricular systole) excluding the first and second sounds.

[0037] Returning to FIG. 2, the configuration of the arithmetic processing unit 10 will be further described.

[0038] The systolic noise measuring section 11 includes an M-Filter 11a, an envelope creating section 11b, and an area calculating section 11c.

[0039] The heart sounds obtained by the heart sound measurement unit 40 are input to the M-Filter 11a. The M-Filter 11a extracts predetermined frequency components from the heart sounds. Specifically, the M-Filter 11a extracts and outputs frequencies affected by aortic stenosis and mitral regurgitation. For example, the M-Filter 11a extracts frequency components of 160 Hz or higher.

[0040] The envelope creation unit 11b creates an envelope of the signal after filtering. Specifically, the envelope creation unit 11b creates the envelope by, for example, finding a statistical approximation curve using a smoothing calculation such as RMS (Root Mean Square). Note that the method of creating the envelope by the envelope creation unit 11b is not limited to this. For example, the envelope may be created using a Hilbert transform. Various conventionally known methods can be used to create the envelope.

[0041] The area calculation unit 11c calculates the area of ​​the late systole surrounded by the envelope and the baseline. Specifically, the area calculation unit 11c receives the envelope created by the envelope creation unit 11b and the late systole section from the measurement section setting unit 12. The area calculation unit 11c then calculates the area surrounded by the envelope for the late systole section set by the measurement section setting unit 12.

[0042] The determination unit 13 makes a determination based on the area in the late systole calculated by the area calculation unit 11c. Specifically, the area calculation unit 11c determines that the subject has aortic stenosis when the area is equal to or greater than a first threshold, and determines that the subject has mitral regurgitation when the area is less than the first threshold and equal to or greater than a second threshold (where 0<second threshold<first threshold).

[0043] The operation of this embodiment will be described in more detail with reference to FIG.

[0044] 4 shows the systolic noise after passing through the M-Filter 11a, and the envelope in the figure shows the envelope output from the envelope generation unit 11b.

[0045] The measurement interval setting unit 12 sets the measurement interval based on the second sound of the phonocardiogram. Specifically, the measurement interval setting unit 12 first detects the start of the second sound based on the end of the T wave in the electrocardiogram. Next, the measurement interval setting unit 12 sets a predetermined interval from the start of the second sound in the past as the measurement interval. In this embodiment, the measurement interval setting unit 12 sets the interval between a time point, for example, 50 ms before the start of the second sound, and a time point further before, for example, 50 ms before that time, as the measurement interval.

[0046] It should be noted that the measurement section set by the measurement section setting unit 12 is not limited to this. For example, the measurement section may simply be set to the latter half of the systole divided into two equal parts, or the measurement section may be set to the latter half of the systole divided into three equal parts. However, setting the measurement section at a position a predetermined distance away from the second heart sound, as in this embodiment, has the advantage of being less susceptible to the influence of the second heart sound.

[0047] Since a phonocardiogram contains a lot of noise, detecting the second sound directly from the phonocardiogram may result in a decrease in detection accuracy. Therefore, the measurement interval setting unit 12 detects the position of the second sound based on the position of the T wave.

[0048] Figure 5 shows examples of systolic murmurs. Figure 5A shows systolic murmurs in a patient with neither aortic stenosis nor mitral regurgitation, with almost no systolic murmur. Figure 5B shows systolic murmurs in a patient with aortic stenosis, with the noise level increasing in the latter half of systole. Figure 5C shows systolic murmurs in a patient with mitral regurgitation, with a nearly constant noise level throughout systole.

[0049] The inventors of the present invention have arrived at the present invention by noticing that the noise levels in the latter half of systole differ greatly between aortic stenosis and mitral regurgitation, and in particular that the noise level in aortic stenosis is significantly higher than the noise level in mitral regurgitation in the latter half of systole.

[0050] Incidentally, when looking at the entire systole, there is a possibility that the noise area of ​​aortic stenosis and the noise area of ​​mitral regurgitation will be similar. Taking this into consideration, in the present invention, aortic stenosis and mitral regurgitation are distinguished from each other based on the noise area in the late systole, where the noise areas of aortic stenosis and mitral regurgitation differ greatly.

[0051] FIG. 6 is a flowchart illustrating a cardiac disease examination method executed by the arithmetic processing unit 10 according to the embodiment.

[0052] First, in step S11, late systolic noise is measured by the systolic noise measuring unit 11. In this embodiment, the area S is measured.

[0053] Next, the determination unit 13 performs a threshold determination process for the area S. If the determination unit 13 determines in step S12 that the area S is equal to or greater than threshold 1, the process proceeds to step S13, where it determines that the subject has aortic stenosis. If the determination unit 13 determines in step S14 that the area S is less than threshold 1 and equal to or greater than threshold 2 (where 0<threshold 2<threshold 1), the process proceeds to step S15, where it determines that the subject has mitral regurgitation. If the determination unit 13 obtains a negative result in step S14, the process proceeds to step S16, where it determines that the subject does not have aortic stenosis or mitral regurgitation.

[0054] <3> summary As described above, according to this embodiment, a phonocardiogram acquisition unit (cardiac sound measurement unit 40) that acquires a phonocardiogram of the subject, a systolic noise measurement unit 11 that measures late systolic noise among the systolic noises in the phonocardiogram, and a determination unit 13 that determines whether the subject has aortic stenosis or mitral regurgitation based on the late systolic noise, can be provided, thereby realizing a cardiac disease examination device and a cardiac disease examination method that can distinguish between aortic stenosis and mitral regurgitation with a simple configuration.

[0055] In other words, since calculations are performed only within a limited range, such as the late systole, the amount of calculation required is small. Furthermore, since this can be achieved through low-computational-intensive processes such as extracting specific frequencies, creating envelopes, and calculating areas, the amount of calculation required is also small. As a result, aortic stenosis and mitral regurgitation can be distinguished with a simple configuration.

[0056] The above-described embodiments are merely examples of specific embodiments of the present invention, and the technical scope of the present invention should not be construed as being limited by these embodiments. In other words, the present invention can be embodied in various forms without departing from the gist or main characteristics thereof.

[0057] In the above embodiment, the measurement interval setting unit 12 sets the late systolic interval based on an electrocardiogram. However, the present invention is not limited to this. The measurement interval setting unit 12 may set the late systolic interval based on a pulse wave diagram. In other words, since the measurement interval setting unit 12 sets the measurement interval based on the second heart sound, various methods capable of detecting the second heart sound can be applied. Therefore, conventional methods for detecting the second heart sound based on a pulse wave diagram can also be applied. In this case, it is sufficient to provide a pulse wave diagram acquisition unit (blood pressure pulse wave measurement unit 30) that acquires a pulse wave diagram of the subject, and a measurement interval setting unit 12 that sets the late systolic interval in which the systolic noise measurement unit 11 measures noise based on the pulse wave diagram. Furthermore, the detection of the second heart sound is not limited to an electrocardiogram or a pulse wave diagram, and may be performed by other methods, such as filtering heart sounds or frequency analysis.

[0058] In the above-described embodiment, aortic stenosis and mitral regurgitation are diagnosed based on the area of ​​the late systolic noise. However, aortic stenosis and mitral regurgitation may also be diagnosed based on other factors, such as the amplitude or power of the late systolic noise or the shape of the noise on the amplitude-time plane within the measurement section of the late systolic noise, without being limited to the area.

[0059] Furthermore, in the above-described embodiment, aortic stenosis and mitral regurgitation are diagnosed by threshold-based area determination, but this is not limiting. For example, aortic stenosis and mitral regurgitation may be diagnosed based on the ratio of the area of ​​the systolic murmur in the late systole to the area of ​​the systolic murmur throughout the systole. That is, as can be seen from Figures 5B and 5C, the ratio should be larger in aortic stenosis than in mitral regurgitation, and therefore aortic stenosis and mitral regurgitation can be diagnosed by threshold-based determination of this ratio.

[0060] In the above-described embodiment, the cardiac disease examination device and cardiac disease examination method of the present invention are described as being embodied by a blood pressure pulse wave examination device 1, but the cardiac disease examination device and cardiac disease examination method of the present invention are not limited to this, and may also be embodied by a device (such as a personal computer) separate from the blood pressure pulse wave examination device.

[0061] In short, the cardiac disease examination device of the present invention only needs to include a phonocardiogram acquisition unit that acquires a phonocardiogram of the subject, a systolic noise measurement unit that measures the late systolic noise among the systolic murmurs in the phonocardiogram, and a determination unit that determines whether the subject has aortic stenosis or mitral regurgitation based on the late systolic noise. Here, the phonocardiogram acquisition unit may be the phonocardiogram measurement unit 40 as in the above-described embodiment, or it may be an input unit such as an interface that inputs heart sound information. [Industrial Applicability]

[0062] The present invention is widely applicable as a heart disease examination apparatus and a heart disease examination method for distinguishing between aortic valve stenosis and mitral valve regurgitation. [Explanation of symbols]

[0063] 1. Blood pressure pulse wave testing device 10. Processing unit 11 Systolic noise measurement unit 11a M-Filter 11b Envelope creation part 11c Area calculation part 12 Measurement section setting section 13 Judgment section 40 Heart sound measurement unit 50 Electrocardiogram measurement unit

Claims

1. A phonocardiogram acquisition unit that acquires a phonocardiogram of a subject; a systolic noise measuring unit that measures late systolic noise among systolic noises of the phonocardiogram; a determination unit that determines whether the subject has aortic stenosis or mitral regurgitation based on the area of ​​the late systolic murmur; Equipped with The determination unit If the area is equal to or greater than a first threshold, the subject is determined to have aortic valve stenosis; If the area is less than the first threshold and is equal to or greater than a second threshold (where 0<second threshold<first threshold), the subject is determined to have mitral regurgitation. Cardiac disease testing equipment.

2. a phonocardiogram acquisition unit for acquiring a phonocardiogram of the subject; a systolic noise measuring unit that measures late systolic noise among systolic noises of the phonocardiogram; a determination unit that determines whether the subject has aortic stenosis or mitral regurgitation based on the area of ​​the late systolic murmur; A cardiac disease examination device comprising:

3. an electrocardiogram acquisition unit for acquiring an electrocardiogram of the subject; a measurement interval setting unit that sets the late systolic interval in which the systolic noise measuring unit measures noise based on the electrocardiogram; Further provided with 3. The cardiac disease examination apparatus according to claim 1 or 2.

4. a pulse wave diagram acquiring unit for acquiring a pulse wave diagram of the subject; a measurement interval setting unit that sets the late systolic interval in which the systolic noise measuring unit measures noise based on the sphygmogram; Further provided with 3. The cardiac disease examination apparatus according to claim 1 or 2.

5. The late systolic period is set based on the second sound of the phonocardiogram. The cardiac disease examination apparatus according to any one of claims 1 to 4.

6. The late systolic section is a section that is a predetermined interval away from the start of the second sound of the phonocardiogram. The cardiac disease examination device according to claim 5.

7. the systolic noise measuring unit includes a filter that extracts a predetermined frequency component from the phonocardiogram, an envelope creating unit that creates an envelope of the filtered signal, and an area calculating unit that calculates the area of ​​the late systole surrounded by the envelope; the determination unit makes the determination based on the area in the late systole calculated by the area calculation unit. The cardiac disease examination apparatus according to any one of claims 1 to 6.

8. The determination unit If the area is equal to or greater than a first threshold, the subject is determined to have aortic valve stenosis; If the area is less than the first threshold and is equal to or greater than a second threshold (where 0<second threshold<first threshold), the subject is determined to have mitral regurgitation. The cardiac disease examination apparatus according to claim 2 or 7.

9. The determination unit: A determination is made as to whether the subject has aortic stenosis or mitral regurgitation based on the ratio of the area of ​​the systolic murmur in the late systole to the area of ​​the systolic murmur throughout the systole. The cardiac disease examination apparatus according to claim 2 or 7.

Images