JP2012016450A - Device for measuring central blood pressure, device for measuring heart load, method for measuring central blood pressure and method for measuring heart load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for measuring central blood pressure which enable exact and easy measurement of the central blood pressure, and a device for measuring a heart load which enables exact measurement of the degree of stress on the heart on the basis of the measured central blood pressure.SOLUTION: The device 1 for measuring a heart load, including the device 52 for measuring the central blood pressure, computes a triple product from first cardiac sound amplitude data in measurement showing the amplitude value of a first cardiac sound, second cardiac sound amplitude data in measurement showing the amplitude value of a second cardiac sound and heart rate data showing the heart rate and can detect the optimum motion intensity from heart load data. The device 52 for measuring the central blood pressure is equipped with a cardiac sound sampling means 3 which samples the cardiac sound of a person to be measured and outputs it as cardiac sound data, a second cardiac sound extracting means 51 which detects the second cardiac sound from the cardiac sound data, measures the amplitude value and makes it the second cardiac sound amplitude data in measurement, and a central blood pressure estimating means 508 which computes a central blood pressure value in measurement from central blood pressure data in ataraxia, based on the ratio between the second cardiac sound amplitude data in measurement and the amplitude data in ataraxia.

Description

  The present invention relates to an apparatus and method that can measure central blood pressure, which is the blood pressure of the aortic root, and an apparatus and method that can measure stress (load) on the heart.

People with health maintenance, obesity, and metabolic syndrome are walking or jogging to improve their condition. In exercise therapy for patients with myocardial infarction or hypertension, exercise is performed for rehabilitation.
Load exercise is less effective if the load (strength) is insufficient, and an excessive load may cause adverse effects on the body. Therefore, it is desirable to determine the best optimal exercise intensity for each person to be measured.

As techniques relating to optimal exercise intensity, those described in Patent Documents 1 and 2 are known.
The method for determining the optimal exercise intensity described in Patent Document 1 performs stepwise load exercise, and determines the amplitude of the first heart sound (S1 sound) generated when the left and right atrioventricular valves close at each load step. It is recorded on a heart sound diagram through a heart sound microphone attached to the chest, and the exercise intensity at the load exercise stage where a change point (HSBP) at which the heart sound amplitude suddenly increases is recognized as the optimum exercise intensity of the subject. That's it.

  In addition, the determination method of the optimal exercise intensity described in Patent Document 2 examines the change in the amplitude of the first heart sound with respect to the change in exercise load intensity, and shows the change in the ratio of the diastole time to one cardiac cycle with respect to the change in exercise load intensity. In the inflection point of the change in the amplitude of the first heart sound, if the change in the ratio of the diastole time to one cardiac cycle is equal to or greater than the first reference value, this inflection point is determined as the optimum exercise intensity. is there.

On the other hand, it is important to measure blood pressure in order to know the health condition not only during exercise but also during calm time. The measured value of blood pressure varies depending on the position to be measured. The central blood pressure, which is measured at the upper heart and is the blood pressure at the beginning of the aorta, is generally lower than the peripheral blood pressure measured at the upper arm, and more accurately reflects the state of the heart load. For example, a patient who was determined to be in need of treatment based on peripheral blood pressure found that no treatment was required according to central blood pressure, and conversely, peripheral blood pressure was thought to require no treatment. The central blood pressure may indicate that treatment is needed.
Although the central blood pressure is the blood pressure at the beginning of the aorta, a device (central blood pressure measuring device) that can be measured with the wrist has been developed. This central blood pressure measurement device estimates central blood pressure from the wrist pulse.

JP 2006-116161 A JP 2007-19777 A

However, this central blood pressure measuring device is an expensive device and is used for measurement at rest, so it cannot be measured while exercising easily. Moreover, since the central blood pressure does not always have a constant difference or ratio with the peripheral blood pressure, it is difficult to estimate the central blood pressure from the peripheral blood pressure that can be easily measured with a small and inexpensive device.
If the central blood pressure can be measured accurately, the stress on the heart can be accurately grasped, so even if you think that you were exercising at your own pace, it is excessive exercise, or even when you are calm, a significant load on the heart due to heart disease It can be recognized that Therefore, a technique capable of accurately and easily measuring the central blood pressure is desired.

Accordingly, an object of the present invention is to provide a central blood pressure measuring device and a central blood pressure measuring method capable of accurately and easily measuring central blood pressure.
It is another object of the present invention to provide a cardiac load measuring device and a cardiac load measuring device that can accurately measure the degree of stress on the heart based on the measured central blood pressure.

The present inventor has found that there is a correlation between the central blood pressure and the amplitude of the second heart sound, and has reached the present invention.
That is, the central blood pressure measurement apparatus of the present invention collects a heart sound of a subject and outputs it as heart sound data, and a second heart sound that detects a second heart sound based on the heart sound data from the heart sound collecting means. An extraction means; a second heart sound amplitude measurement means for measuring an amplitude value from the second heart sound detected by the second heart sound extraction means and outputting the amplitude value as amplitude data at the time of second heart sound measurement; Storage means for storing the central blood pressure value as the central blood pressure data at rest and the amplitude value of the second heart sound as the amplitude data at rest, the second heart sound measurement amplitude data from the second heart sound amplitude measuring means, and the storage means Central blood pressure estimating means for calculating a central blood pressure value at the time of measurement from the calm central blood pressure data read from the storage means on the basis of the ratio to the calm amplitude data read from the storage means. To.

  In the central blood pressure measurement method according to the present invention, a heart sound collecting step for collecting the heart sound of the subject as heart sound data, and a second heart sound extraction for detecting the second heart sound based on the heart sound data collected by the heart sound collecting step. A second heart sound amplitude measuring step of measuring an amplitude value from the second heart sound detected by the second heart sound extraction step and measuring it as amplitude data at the time of second heart sound measurement, and a measurement by the second heart sound amplitude measuring step. Based on the ratio between the measured amplitude data of the second heart sound and the amplitude data of the second heart sound when the subject is calm, the central blood pressure value when the subject is calm is calculated. A central blood pressure estimating step of calculating a central blood pressure value at the time of measurement from the central blood pressure data at rest.

  In the present invention, first, the heart sound collecting means collects the heart sound of the person to be measured in the heart sound collecting step to obtain heart sound data. Next, in the second heart sound extraction step, the second heart sound extraction means detects the second heart sound based on the heart sound data. Next, an amplitude value is measured from the second heart sound detected by the second heart sound amplitude measuring means in the second heart sound amplitude measuring step to obtain second heart sound measurement amplitude data. In the central blood pressure estimating step, the central blood pressure estimating means measures the second heart sound measurement amplitude data measured by the second heart sound amplitude measuring step, and the calm time amplitude which is the amplitude value of the second heart sound when the subject is calm. Based on the ratio with the data, the central blood pressure value at the time of measurement can be estimated by calculating the central blood pressure value at the time of measurement from the central blood pressure data at the time of calming of the measurement subject.

The heart sound collecting means can be formed by an acceleration sensor.
When the heart sound collection means is an acceleration sensor, the second heart sound extraction means collects an electrocardiogram of the measurement subject and outputs it as electrocardiogram data, and an electrocardiogram from the electrocardiogram collection means. Reference timing detection means for detecting an R wave from data, and a gate signal for generating a gate signal indicating a predetermined period including the first heart sound corresponding to the R wave from the generation timing of the R wave detected by the reference timing detection means Generating means; heart sound data from the heart sound collecting means; first heart sound detecting means for detecting a first heart sound from heart sound data while the gate signal is output by the gate signal generating means; and the first heart sound detecting means. And a second heart sound detecting means for detecting a second heart sound based on the first heart sound detected by the heart sound detecting means.

  The electrocardiogram data is collected by the electrocardiogram collection means, and the R wave is detected by the reference timing detection means. The first heart sound detecting means includes the first heart sound detecting means included in the gate signal by generating a gate signal indicating a predetermined period including the first heart sound corresponding to the R wave from the generation timing of the R wave detected by the gate signal generating means. One heart sound can be detected. If the first heart sound can be detected, the second heart sound can be detected by the second heart sound detecting means. Therefore, the second heart sound can be extracted even if noise due to movement is collected in the heart sound data in addition to the heart sound by the acceleration sensor. Can do.

  The heart load measuring device of the present invention is a heart sound collecting means for collecting a heart sound of a measured person and outputting it as heart sound data; an electrocardiographic collecting means for collecting the electrocardiogram of the measured person and outputting it as electrocardiographic data; A reference timing detecting means for detecting an R wave from electrocardiographic data from the heart sound collecting means, and a predetermined period including a first heart sound corresponding to the R wave from the generation timing of the R wave detected by the reference timing detecting means. A first signal for detecting a first heart sound from heart sound data from the heart sound data generated by the gate signal generating means for generating a gate signal and heart sound data from the heart sound collecting means during output of the gate signal by the gate signal generating means; A heart sound detecting means; a second heart sound detecting means for detecting a second heart sound based on the first heart sound detected by the first heart sound detecting means; and a second heart detected by the second heart sound extracting means. The second heart sound amplitude measuring means for measuring the amplitude value from the first heart sound and outputting it as amplitude data at the time of second heart sound measurement, and measuring the amplitude value from the first heart sound detected by the first heart sound detecting means to measure the first heart sound. A first heart sound amplitude measuring means for outputting as amplitude data, a heart rate counting means for measuring the heart rate of the measured person and outputting it as heart rate data, and a time for measuring the first heart sound from the first heart sound amplitude measuring means. Exercise intensity calculating means for calculating a triple product from amplitude data, second heart sound measurement amplitude data from the second heart sound amplitude measuring means, and heart rate data from the heart rate counting means, and outputting the result as cardiac load data; The cardiac load data from the exercise intensity calculation means includes overload detection means for detecting a change point of the gradient with respect to the exercise intensity.

  The heart load measuring method of the present invention includes a heart sound collecting step in which a heart sound of a measured person is collected by a heart sound collecting means to obtain heart sound data, and an electrocardiographic data obtained by collecting the electrocardiogram of the measured person by an electrocardiographic collecting means. From the electrocardiogram collection step, the reference timing detection step for detecting the R wave from the electrocardiogram data collected by the heart sound collection step, and the R wave generation timing detected by the reference timing detection step, A first heart sound detecting step for detecting the first heart sound from heart sound data of a predetermined period including the corresponding first heart sound, and a second heart sound for detecting the second heart sound based on the first heart sound detected by the first heart sound detecting step. A heart sound detection step, and a second heart sound amplitude measurement step that measures amplitude values from the second heart sounds detected in the second heart sound detection step to obtain amplitude data during second heart sound measurement. Measuring the amplitude value from the first heart sound detected by the first heart sound detecting step to obtain amplitude data at the time of first heart sound measurement, and measuring the heart rate of the subject A heart rate counting step output as heart rate data, first heart sound measurement amplitude data from the first heart sound amplitude measurement step, second heart sound measurement amplitude data from the second heart sound amplitude measurement step, and the heart rate An exercise intensity calculation step for calculating a triple product from heart rate data from the counting step to obtain cardiac load data, and an overload for detecting a change point of a gradient with respect to the exercise intensity for the cardiac load data from the exercise intensity calculation step And a detection step.

  According to the present invention, the triple product of the systolic force, blood pressure and heart rate indicates the oxygen demand of the heart, ie the heart stress state. Therefore, the contractile force is the first heart sound amplitude data as the first heart sound, the blood pressure is the second heart sound amplitude data from the second heart sound amplitude measuring means as the second heart sound indexing the central blood pressure, and the heart rate is the heart rate. By calculating the triple product using the heart rate data from the counting means, it is possible to obtain cardiac load data indicating the stress state of the heart.

  It is desirable to provide notifying means for giving a warning when the overload detecting means detects a change point of the gradient or when the change point is exceeded. If it is for the purpose of medical treatment, if the exercise load exceeds the optimum exercise intensity, or even if it is for the purpose of maintaining health or enhancing physical fitness, the exercise exercise will exceed the optimum exercise intensity and the prescribed exercise intensity If this happens, there is concern about adverse effects on the body. Therefore, in such a case, by giving notification that the notification means warns, excessive load movement is suppressed, so that an unexpected accident can be prevented.

  Preferably, the heart rate counting means counts heart rate data from an interval of R waves detected by the reference timing detection means or an interval of first heart sounds detected by the first heart sound detection means. The R wave, the first heart sound, and the second heart sound are measured in the process of measuring exercise intensity. Therefore, by measuring the heart rate from the interval of the R wave, the interval of the first heart sound, and the interval of the second heart sound, the measurement can be performed without providing a means for collecting the heart rate.

  According to the central blood pressure measuring apparatus and method of the present invention, the amplitude value of the second heart sound is measured, and the central blood pressure value during exercise is calculated from the ratio between the central blood pressure value during calm and the amplitude value of the second heart sound. By estimating, the central blood pressure can be measured accurately and easily. Further, according to the cardiac load measuring apparatus and method of the present invention, the degree of stress on the heart can be accurately measured based on the measured central blood pressure.

It is a figure which shows the to-be-measured person who measures cardiac stress with the cardiac load measuring apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the cardiac load apparatus shown in FIG. (A) is a block diagram showing an example of a heart sound collection means, (B) is a block diagram showing an example of an electrocardiogram collection means (A) is a figure which shows the position when measuring a heart sound and an electrocardiogram, (B) is a perspective view for demonstrating a sensor apparatus. It is a figure which shows an example of an electrocardiogram and a heart sound chart. It is a graph which shows the relationship between the ratio of the amplitude at the time of calm of a 2nd heart sound and exercise | movement, systolic blood pressure value, and exercise intensity. It is a graph which shows the relationship between exercise intensity and triple product. It is a block diagram which shows the cardiac load measuring apparatus which concerns on Embodiment 1 of this invention.

(Embodiment 1)
A cardiac load measuring apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the cardiac load measuring apparatus 1 measures the optimal exercise intensity by subjecting the subject to exercise exercise using an exercise load instrument A. As shown in FIG. 2, the cardiac load measuring device 1 includes an electrocardiogram collection unit 2, a heart sound collection unit 3, a heart rate collection unit 4, a control unit 5, a display unit 6, and a printing unit 7. Yes.

The electrocardiogram collection means 2 can be formed of, for example, a measurement electrode 21, an amplification means 22, and an AD conversion means 23 as shown in FIG. The measurement electrode 21 is two terminals for collecting, as an electrocardiographic signal, a potential generated on the body when the heart of the measurement subject pulsates. The amplifying unit 22 is an amplifier that amplifies an electrocardiogram signal. The AD conversion unit 23 has a function of converting the amplified electrocardiogram signal into electrocardiogram data which is digital data and outputting the electrocardiogram signal to the control unit 5.
The heart sound collection means 3 can be formed of, for example, an acceleration sensor 31, an amplification means 32, and an AD conversion means 33 as shown in FIG. In the present embodiment, the sensor device 8 (see FIG. 4) in which the measurement electrode 21 and the acceleration sensor 31 are housed together in a housing is used.

  The acceleration sensor 31 is a sensor that measures acceleration in each moving direction, and has a function of collecting a heart sound based on the pulsation of the heart of the measurement subject as an acceleration and outputting it as a heart sound signal. As shown in FIG. 4 (B), the acceleration sensor 31 is attached to the measurement subject by a sticking means such as a double-sided tape provided on the attachment surface. Various types of acceleration sensors 31 can be used as long as acceleration in any direction can be measured.

  For example, if the acceleration sensor 31 is a MEMS type, an electrostatic capacitance detection system that measures acceleration by detecting a change in capacitance between the movable part and the fixed part of the sensor element, the sensor element movable part and the fixed part, Piezoresistive method that measures the acceleration by detecting the distortion of the spring caused by acceleration by the piezoresistive element placed on the spring connecting the, and detects the change in convection of the hot air current generated by the heater by thermal resistance etc. By doing so, it is possible to adopt a heat detection method for measuring acceleration. In any case, the acceleration sensor 31 is desirably a small sensor that does not interfere with the movement when attached to the measurement subject. The amplification means 32 is an amplifier that amplifies the heart sound signal. The AD conversion means 33 has a function of converting the amplified heart sound signal into heart sound data which is digital data and outputting the heart sound data to the control means 5.

Between the electrocardiogram collection means 2 and the control means 5, and between the heart sound collection means 3 and the control means 5, as shown in FIG. They are connected by a cable 9. By doing so, it is pulled by the cable 9 every time it moves, so that it does not interfere with the load movement.
The heart rate sampling means 4 outputs the heart rate of the person to be measured as heart rate data. For example, a device that is attached to the earlobe, wrist, torso, or around the heart can be used as the heart rate collecting means 4, but in this embodiment, a clip type that sandwiches the earlobe is employed.

As shown in FIG. 2, the control means 5 measures the central blood pressure value and the cardiac load by calculation, and may be a personal computer that executes a cardiac stress measurement program including a central blood pressure measurement program. it can.
The control means 5 includes a heart sound input means 502, an electrocardiogram input means 501, a reference timing detection means 503, a gate signal generation means 504, a first heart sound detection means 505, a second heart sound detection means 506, and a second heart sound. Amplitude measurement means 507, central blood pressure estimation means 508, heart rate input means 509, heart rate counting means 510, storage means 511, first heart sound amplitude measurement means 512, exercise intensity calculation means 513, overload detection Means 514.

  The heart sound input means 502 is an interface that inputs the heart sound data from the heart sound collection means 3 to the control means 5 and stores it in the storage means 511. The electrocardiogram input unit 501 is an interface that inputs the electrocardiogram data from the electrocardiogram collection unit 2 to the control unit 5 and stores it in the storage unit 511.

  The reference timing detection unit 503 has a function of referring to the electrocardiogram data stored in the storage unit 511 and detecting an R wave based on the electrocardiogram data. The gate signal generation unit 504 outputs a gate signal indicating a predetermined period including the first heart sound corresponding to the R wave from the R wave detected by the reference timing detection unit 503, that is, a period before the second heart sound. It has. The first heart sound detecting means 505 has a function of detecting a peak waveform from heart sound data while a gate signal is being output. The second heart sound detection means 506 has a function of detecting the second heart sound based on the first heart sound detected by the first heart sound detection means 505. The second heart sound amplitude measuring means 507 has a function of measuring an amplitude value from the second heart sound detected by the second heart sound detecting means 506 and outputting it as amplitude data at the time of second heart sound measurement. The central blood pressure estimating unit 508 has a function of calculating the central blood pressure based on the second heart sound measurement amplitude data from the second heart sound amplitude measuring unit 507. The heartbeat input means 509 is an interface that inputs the heartbeat data from the heartbeat collecting means 4 to the control means 5 and stores it in the storage means 511. Heart rate counting means 510 has a function of counting heart rate based on heart rate data.

The storage unit 511 is a nonvolatile memory in which each data can be read and written. As the storage means 511, a hard disk device capable of high-speed access with a large capacity can be adopted. The storage means 511 stores heart sound data, electrocardiographic data, and heart rate data at the time of measurement. The storage means 511 stores the central blood pressure value of the subject at rest as the central blood pressure data at rest, and the amplitude value of the second heart sound as the amplitude data at rest.
The first heart sound amplitude measuring means 512 has a function of measuring an amplitude value from the first heart sound detected by the first heart sound detecting means 505 and outputting it as amplitude data at the time of first heart sound measurement.
The exercise intensity calculation means 513 is the first heart sound measurement amplitude data from the first heart sound amplitude measurement means 512, the second heart sound measurement amplitude data from the second heart sound amplitude measurement means 507, and the heart rate from the heart rate counting means 510. It has a function to calculate triple products from numerical data and output them as cardiac load data. The overload detection unit 514 has a function of detecting a change point of the gradient with respect to the exercise intensity with respect to the cardiac load data from the exercise intensity calculation unit 513.

Further, the control unit 5 includes a notification unit 515, an exercise load input unit 516, a suppression unit 517, a display control unit 518, and a print control unit 519.
The notification unit 515 has a function of notifying that a warning is given when the overload detection unit 514 detects a change point of the gradient or when a predetermined intensity is exceeded from the change point. The predetermined intensity at this time exceeds the optimal exercise intensity, but an exercise load that does not cause an excessive burden on the heart is preferable and can be determined according to the subject. This notification means 515 is notified by a continuous sound or intermittent sound, a sound such as a voice message, lighting or blinking with a lamp (not shown), a message display by the display means 6 via the display control means 518, or the like. Can be.

The exercise load input unit 516 is an interface that inputs exercise intensity data from the exercise load device A to the control unit 5 and stores it in the storage unit 511.
Based on the optimal exercise intensity detected by the overload detection unit 514, the suppression unit 517 controls the exercise equipment A to prevent the load exercise by the measurement subject from exceeding the optimal exercise intensity. It has a function to output.
The display control unit 518 has a function of controlling display on the display unit 6. The print control unit 519 has a function of controlling printing on the printing unit 7.

  The display means 6 can be a CRT, LCD, or organic EL display. The printing means 7 can be an ink jet printer, a laser printer, a dot impact printer, or a thermal transfer printer that can print on a paper medium.

  In the present embodiment, the second heart sound extraction composed of the heart sound sampling means 3, the heart sound input means 502, the reference timing detection means 503, the gate signal generation means 504, the first heart sound detection means 505, and the second heart sound detection means 506. The central blood pressure estimation device 52 is constituted by the means 51, the second heart sound amplitude measuring means 507, and the central blood pressure estimation means 508.

A measurement method and operation contents of the cardiac load measuring apparatus according to the first embodiment of the present invention configured as described above will be described with reference to the drawings.
When the measurement subject performs a load exercise, first, the acceleration sensor 31 and the measurement electrode 21 as the sensor device 8 are attached to the measurement subject. Although the acceleration sensor 31 is mounted on the chest of the measurement subject, it is preferable that the acceleration sensor 31 is also disposed on the sternum as shown in FIG. Further, the arrangement position is preferably the sternum pattern P1 even on the sternum. The heart rate collecting means 4 is worn around the earlobe, wrist, waist, and near the heart.

Next, a load exercise is started by the person to be measured. In the load exercise, the person to be measured gets on the bicycle ergometer, which is the exercise load apparatus A, with the sensor device 8 mounted, and continuously presses the pedal.
The heart sound signal from the acceleration sensor 31 is amplified by the amplification means 32, and the heart sound signal amplified every predetermined time by the AD conversion means 33 is sampled and converted into heart sound data as digital data (heart sound collection step). The electrocardiographic signal from the measurement electrode 21 is amplified by the amplifying unit 22, and the electrocardiographic signal amplified every predetermined time by the AD converting unit 23 is sampled and converted into electrocardiographic data which is digital data ( ECG collection step).

  The heart sound input means 502 of the control means 5 inputs the heart sound data from the heart sound collection means 3, the electrocardiogram input means 501 inputs the electrocardiogram data from the electrocardiogram collection means 2, and the heartbeat input means 509 is the heartbeat collection means 4. The heart rate data is input to the storage means 511 together with the exercise intensity data from the exercise load device A (heart rate collection step). The heart rate counting means 510 reads heart rate data from the storage means 511, counts the heart rate, and stores it as heart rate data in the storage means 511 (heart rate counting step).

The reference timing detection unit 503 detects the R wave based on the electrocardiographic data stored in the storage unit 511. Here, the R wave will be described with reference to FIG.
Since the R wave is a wave observed at the end diastole of the heart, the R wave is a first heart sound S1 generated by the closure of the atrioventricular valve (mitral valve / tricuspid valve) and the artery when the heart beats. It can be used as a reference for detecting the second heart sound S2 generated by closing the valve (aortic valve / pulmonary valve).
The R wave has a larger peak than the P wave, Q wave, S wave, and T wave, and rises sharply. Therefore, the reference timing detection unit 503 can detect the R wave relatively easily by detecting the highest peak electrocardiographic data.
The reference timing detection unit 503 that has detected the R wave outputs a notification of detection to the gate signal generation unit 504 (reference timing detection step).
The gate signal generation unit 504 that has received the notification that the R wave has been detected, based on the timing of the R wave, generates a gate signal G indicating the period from the R wave to the second heart sound S2 (see FIG. 5). Output to the first heart sound detection means 505. The period from this R wave to before the second heart sound S2 varies among individuals and varies depending on the amount of exercise of the load exercise. The period from the R wave to the first heart sound S1 also varies depending on the condition of the subject. Accordingly, if the gate signal G is too short, the first heart sound S1 is not included, and if it is too long, the second heart sound S2 is included. Therefore, in the present embodiment, a predetermined value determined by statistically measuring young people to elderly people is used.

  The first heart sound detecting means 505 extracts a peak waveform (first heart sound S1) from heart sound data while the gate signal G is being output (first heart sound detecting step). The first heart sound amplitude measuring means 512 measures the amplitude value V1 of the peak waveform and stores it in the storage means 511 as first heart sound amplitude data. The heart sound during the output of the gate signal always includes the first heart sound S1. That is, by limiting the range in which data corresponding to the first heart sound S1 is extracted from the heart sound data by the gate signal G, the second heart sound S2 and noise can be excluded. Therefore, it is possible to detect the first heart sound S1, which is a peak waveform within the period of the gate signal.

  At this time, the first heart sound amplitude measuring means 512 reads the first heart sound amplitude data for 10 times stored in the storage means 511, calculates the average value, and stores it as the first heart sound average value data for one time. (First heart sound amplitude measurement step). By averaging the first heart sound amplitude data for a predetermined number of times, even if the amplitude of the first heart sound S1 varies, the influence on the whole can be suppressed. This averaging can be averaged using other statistical methods in addition to simply averaging the first heart sound amplitude data every ten times as in the present embodiment.

  When the first heart sound S1 is detected, the second heart sound detecting means 506 detects the second heart sound S2. Since the first heart sound S1 can be detected, the second heart sound S2 can be easily detected by detecting the next peak waveform after the gate signal G disappears as the second heart sound S2 (second heart sound detecting step). . If the second heart sound S2 can be detected, the second heart sound amplitude measuring means 507 detects it as second heart sound measurement amplitude data indicating the amplitude width of the peak waveform (amplitude value V2 of the second heart sound) and stores it in the storage means 511. . Similarly to the first heart sound amplitude data, the second heart sound measurement amplitude data can be an average value (second heart sound amplitude measurement step).

  The central blood pressure estimation means 508 is based on the ratio between the second heart sound measurement amplitude data from the second heart sound amplitude measurement means 507 and the calm amplitude data read from the storage means 511, and is in a calm state read from the storage means 511. A central blood pressure value at the time of measurement is calculated from the central blood pressure data. That is, the central blood pressure value at the time of the subject's calm and the amplitude value V2 of the second heart sound S2 are measured in advance and stored in the storage means 511, and the second during the measurement subject's exercise (measurement time). The rate of increase of the heart sound amplitude value V2 is calculated to estimate the central blood pressure value during exercise.

  FIG. 6 is a graph in which the vertical axis represents the ratio of the amplitude of the second heart sound during calm and exercise, the systolic blood pressure (SBP) value, and the horizontal axis represents the exercise intensity. From this graph, it can be seen that there is a proportional relationship between the amplitude of the second heart sound and the systolic blood pressure. Therefore, by estimating the central blood pressure value from the amplitude value of the second heart sound by calculation, the central blood pressure that is difficult to measure even during exercise can be measured easily and accurately. Further, if the amplitude value of the second heart sound can be measured, the central blood pressure at the time of measurement can be measured, so that it can be measured with an inexpensive device.

Next, the exercise intensity calculation unit 513 calculates a triple product from the first heart sound measurement amplitude data, the second heart sound measurement amplitude data, and the heart rate data accumulated in the storage unit 511, and outputs it as heart load data. To do.
FIG. 7 is a graph in which the vertical axis represents this triple product and the horizontal axis represents exercise intensity. From this graph, the change point at which the gradient of the approximate value line suddenly increases is the optimum exercise intensity. Therefore, the exercise intensity calculation means 513 obtains a broken line of the approximate value line from the cardiac load data which is the triple product numerical data obtained by multiplying the amplitude value of the first heart sound, the amplitude value of the second heart sound, and the heart rate, The optimal exercise intensity can be detected based on the intensity of the exercise.

  When the optimal exercise intensity is detected, the exercise intensity calculating unit 513 stores the exercise intensity calculating unit 513 in the storage unit 511 in association with identification data (for example, a name or ID) that specifies a predetermined measurement subject. By storing the optimal exercise intensity in the storage unit 511 in association with the identification data as described above, the cardiac load measuring apparatus 1 can register the optimal exercise intensity for each person to be measured.

  In the process in which the exercise intensity calculating means 513 detects the optimum exercise intensity, the graph shown in FIG. 7 can be drawn. This graph can be displayed on the display means 6 via the display control means 518 or via the print control means 519. The printing means 7 can print on a paper medium.

If the optimal exercise intensity can be detected in this way, a warning is notified from the notification means 515 when the load exercise exceeds the optimal exercise intensity, or exceeds the optimal exercise intensity and exceeds the predetermined exercise intensity. Can be avoided.
If the person to be measured is registered by measuring the optimum exercise intensity, the notification means 515 reads out the optimum exercise intensity associated with the identification data for specifying the person to be measured from the storage means 511, and the exercise load device By notifying the warning in comparison with the exercise intensity data from A, the optimum exercise can be performed without measuring the optimum exercise intensity again when performing the load handling again.

(Embodiment 2)
The cardiac load measuring device 10x according to Embodiment 2 of the present invention is characterized in that the heart rate is obtained from the R wave, the first heart sound, or the second heart sound. In FIG. 8, the same components as those in FIG.
The heart rate counting means 510x of the cardiac load measuring apparatus 10x shown in FIG. 8 measures the heart rate by measuring the interval P1 (see FIG. 5) between the R wave detected by the reference timing detection means 503 and the next R wave. Count.
The heart rate counting means 510x can count the heart rate from the interval P1 based on the first heart sound S1 detected by the first heart sound detecting means 505.

  As described above, the heart rate is counted from the R wave interval and the first heart sound interval based on the R wave, the first heart sound, and the second heart sound measured in the process of measuring the exercise intensity. As in the case of the one cardiac load measuring device 1, the measurement can be performed without providing a means for collecting a heart rate (heart rate collecting means 4).

  The present invention is suitable for measuring the central blood pressure, which is the blood pressure of the aortic root, and for measuring stress on the heart, and is particularly suitable for measuring the optimal exercise intensity.

DESCRIPTION OF SYMBOLS 1,10x Heart load measuring apparatus 2 Electrocardiogram collection means 21 Measurement electrode 22 Amplification means 23 AD conversion means 3 Heart sound collection means 31 Acceleration sensor 32 Amplification means 33 AD conversion means 4 Heart rate collection means 5 Control means 51 Second heart sound extraction means 52 Central blood pressure estimation device 501 ECG input means 502 Heart sound input means 503 Reference timing detection means 504 Gate signal generation means 505 First heart sound detection means 506 Second heart sound detection means 507 Second heart sound amplitude measurement means 508 Central blood pressure estimation means 509 Heart rate input Means 510, 510x Heart rate counting means 511 Storage means 512 First heart sound amplitude measurement means 513 Exercise intensity calculation means 514 Overload detection means 515 Notification means 516 Exercise load input means 517 Inhibition means 518 Display control means 519 Print control means 6 Display means 7 Printing means 8 Capacitors 9 cable S1 first heart sound S2 second heart sound G gate signals V1, V2 amplitudes P1~P3 interval A exercise device

Claims (8)

A heart sound collecting means for collecting the heart sound of the measured person and outputting it as heart sound data;
Second heart sound extraction means for detecting a second heart sound based on heart sound data from the heart sound collection means;
Second heart sound amplitude measuring means for measuring an amplitude value from the second heart sound detected by the second heart sound extracting means and outputting as amplitude data at the time of second heart sound measurement;
Storage means for storing the central blood pressure value of the subject at rest as the central blood pressure data at rest and the amplitude value of the second heart sound as the amplitude data at rest;
Based on the ratio between the second heart sound measurement amplitude data from the second heart sound amplitude measurement means and the calm amplitude data read from the storage means, the center at the time of measurement from the calm central blood pressure data read from the storage means A central blood pressure measuring apparatus comprising central blood pressure estimating means for calculating a blood pressure value.   The central blood pressure measurement device according to claim 1, wherein the heart sound collection means is formed by an acceleration sensor. The second heart sound extraction means includes
An electrocardiogram collecting means for collecting the electrocardiogram of the measurement subject and outputting it as electrocardiogram data;
Reference timing detection means for detecting an R wave from electrocardiographic data from the electrocardiogram collection means;
Gate signal generation means for generating a gate signal indicating a predetermined period including the first heart sound corresponding to the R wave from the generation timing of the R wave detected by the reference timing detection means;
First heart sound detection means for detecting a first heart sound from heart sound data from the heart sound collection means, the heart sound data being output by the gate signal generation means;
The central blood pressure measuring device according to claim 2, further comprising second heart sound detecting means for detecting a second heart sound based on the first heart sound detected by the first heart sound detecting means. A heart sound collecting means for collecting the heart sound of the measured person and outputting it as heart sound data; an electrocardiographic collecting means for collecting the electrocardiogram of the measured person and outputting it as electrocardiographic data;
Reference timing detection means for detecting an R wave from electrocardiographic data from the heart sound collection means;
Gate signal generation means for generating a gate signal indicating a predetermined period including the first heart sound corresponding to the R wave from the generation timing of the R wave detected by the reference timing detection means;
First heart sound detection means for detecting a first heart sound from heart sound data from the heart sound collection means, the heart sound data being output by the gate signal generation means;
Second heart sound detecting means for detecting a second heart sound based on the first heart sound detected by the first heart sound detecting means;
Second heart sound amplitude measuring means for measuring an amplitude value from the second heart sound detected by the second heart sound detecting means and outputting as amplitude data at the time of second heart sound measurement;
First heart sound amplitude measuring means for measuring an amplitude value from the first heart sound detected by the first heart sound detecting means and outputting it as amplitude data at the time of first heart sound measurement;
A heart rate counting means for measuring the heart rate of the measurement subject and outputting as heart rate data;
A triple product is obtained from the first heart sound measurement amplitude data from the first heart sound amplitude measurement means, the second heart sound measurement amplitude data from the second heart sound amplitude measurement means, and the heart rate data from the heart rate counting means. Exercise intensity calculation means for calculating and outputting as cardiac load data;
An apparatus for measuring cardiac load, comprising: overload detection means for detecting a change point of a gradient with respect to exercise intensity with respect to cardiac load data from the exercise intensity calculation means.   5. The cardiac load measuring device according to claim 4, further comprising notification means for giving a warning when the overload detecting means detects a change point of the gradient or when the change point is exceeded.   The heart according to claim 4 or 5, wherein the heart rate counting means counts heart rate data from an interval of R waves detected by the reference timing detection means or an interval of first heart sounds detected by the first heart sound detection means. Load measuring device. A heart sound collecting step for collecting heart sound of the person to be measured by heart sound collecting means to obtain heart sound data;
A second heart sound extraction step of detecting a second heart sound based on the heart sound data collected by the heart sound collection step;
A second heart sound amplitude measuring step of measuring an amplitude value from the second heart sound detected by the second heart sound extraction step and measuring it as amplitude data at the time of second heart sound measurement;
Based on the ratio between the amplitude data of the second heart sound measured in the second heart sound amplitude measurement step and the amplitude data of the second heart sound when the subject is at rest, the amplitude data of the second heart sound is at rest. A central blood pressure measuring method, comprising: a central blood pressure estimating step for calculating a central blood pressure value at the time of measurement of a central blood pressure value at the time of calming from the central blood pressure data at rest. A heart sound collecting step for collecting heart sound of the person to be measured by heart sound collecting means to obtain heart sound data;
An electrocardiogram collection step in which the electrocardiogram of the measurement subject is collected by an electrocardiogram collection means to be electrocardiogram data;
A reference timing detection step of detecting an R wave from the electrocardiogram data collected by the heart sound collection step;
A first heart sound detecting step of detecting a first heart sound from heart sound data of a predetermined period including the first heart sound corresponding to the R wave from the generation timing of the R wave detected by the reference timing detecting step;
A second heart sound detecting step for detecting a second heart sound based on the first heart sound detected by the first heart sound detecting step;
A second heart sound amplitude measuring step of measuring an amplitude value from the second heart sound detected by the second heart sound detecting step and setting it as amplitude data at the time of second heart sound measurement;
A first heart sound amplitude measuring step of measuring an amplitude value from the first heart sound detected in the first heart sound detecting step and setting it as amplitude data at the time of first heart sound measurement;
A heart rate counting step of measuring the heart rate of the measurement subject and outputting as heart rate data;
A triple product is obtained from the first heart sound measurement amplitude data from the first heart sound amplitude measurement step, the second heart sound measurement amplitude data from the second heart sound amplitude measurement step, and the heart rate data from the heart rate counting step. An exercise intensity calculation step for calculating cardiac load data;
An overload detection step of detecting a change point of a gradient with respect to the exercise intensity with respect to the cardiac load data from the exercise intensity calculation step.

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