KR20090127517A - Heart monitoring system - Google Patents

Abstract

PURPOSE: A heart monitoring device considering the viscosity of the blood is provided to check a health state of an object easily by calculating a cardiac output by calculating a pulse transmission time, a pulse transmission velocity, a blood pressure, and the viscosity through the measured pulse wave. CONSTITUTION: One or more sensors(10) are attached to a preset part of an object. A controller(20) processes a signal from the sensor. An operator(30) calculates the cardiac output using a digital pulse wave signal from the controller. A program is installed in a display device to display and calculate a P-V line of the heart. A receiver(21) receives the pulse wave signal measured by the sensor. An amplifier(22) amplifies the pulse wave signal received through the receiver. A filer(23) removes the noise included in the received pulse wave signal.

Description

Heart monitoring device considering the viscosity of blood {HEART MONITORING SYSTEM}

The present invention relates to a cardiac monitoring device. More specifically, the present invention relates to a cardiac monitoring device. And a cardiac monitoring device.

Currently, blood pressure measurement, ultrasound or MRI is used to predict vascular diseases caused by arteriosclerosis.

However, the diagnostic method using ultrasound or MRI consumes a lot of costs, and the blood pressure measurement method is relatively easy to measure by measuring the blood pressure of the systolic and diastolic groups, but has a disadvantage in reliability.

In addition, in the conventional method, predicting atherosclerosis using only the waveform may cause an error. People with vascular diseases, such as atherosclerosis, will have an increased blood clot and an increase in LDL or cholesterol in the blood, making the blood very sticky. That is, since the viscosity of the blood is higher than that of the normal person, correction is necessary but the conventional method does not consider this at all.

The present invention is to solve the problems of the prior art as described above, by measuring the pressure waveform and blood viscosity of the human body in a simple, easy and inexpensive non-probe method, the size of the heart, contractility of the heart (contractility), An object of the present invention is to provide a cardiac monitoring device capable of predicting vascular disease by calculating output and PV diagrams.

In order to achieve the above object, according to the present invention there is provided a cardiac monitoring device for use in predicting vascular disease, the device comprising one or more sensors attached to a predetermined area of the object to be measured, and processing the signal provided from the sensor A control device for receiving and amplifying a pulse wave signal measured by the sensor, removing noise contained in the signal, and converting the signal into a digital pulse wave signal; A calculation and display device with a program configured to calculate cardiac output using the transmitted digital pulse wave signal, and to display the state of the heart and displaying figures and figures (PV diagram of the heart); The display device may be interconnected by wire.

In the present invention, the program calculates the propagation time of the pulse wave using the time difference of the digital pulse wave (pressure waveform), calculates the blood flow from the modeling by calculating the characteristics of the pressure waveform over time, using a viscosity model And calculating the cardiac output through a mathematical model of the cardiac output by reflecting the viscosity of the blood, and using the calculated values, calculating and displaying a PV diagram through the correlation between the left ventricle and the aorta.

In one embodiment, the cardiac output is determined by the product of the difference in the pressure waveform of the aorta and the brachial artery and the blood flow. Therefore, it is very difficult to predict blood flow in a non-probe way. Therefore, in the present patent, it is calculated through the linear regression analysis between the pressure waveform and pulse wave propagation time, the output of the heart is calculated through the following equation.

Where

p ₁ (t) = blood pressure in the aorta,

Q ₁ (t) = blood flow discharged from the heart and through the peripheral blood system,

Q _IN (t) = volume of blood discharged from the left ventricle of the heart,

Q _IN (t) -Q ₁ (t) = blood flow stored in the aorta,

C ₁ = proximal compliance,

z1: characteristic size for the entire arterial system,

τ _y : yield stress,

R: radius of blood vessels,

       k: constant value,

       T = heart rate cycle

Indicates.

According to another embodiment of the present invention, there is provided a cardiac monitoring device used for predicting vascular disease, wherein the device is one or more sensors attached to a predetermined portion of the object to be measured, and a control for processing a signal provided from the sensor An apparatus, comprising: a control device having a function of receiving and amplifying a pulse wave signal measured by the sensor, removing noise included in the signal, and converting the signal into a digital pulse wave signal, wherein the control device comprises: A control unit programmed to calculate cardiac output using a digital pulse wave signal, calculate and display a PV diagram of the heart, and to transmit and display the calculated PV diagram to an external display device connected through a wired connector. It is characterized by.

In one embodiment, the control unit calculates the pulse wave propagation time using the time difference of the waveform of the digital pulse wave, calculates the pulse wave transmission rate and blood pressure through this, calculates the viscosity of the blood using the viscosity model, After calculating the cardiac output using a mathematical model of the cardiac output using them, the calculated values can be programmed to obtain the PV plot through the correlation of the left ventricle and the aorta, and the pulse wave propagation time is Can be calculated through feature point detection.

According to the present invention, without using expensive equipment such as MRI for diseases such as heart disease, simply measuring the pulse wave of the measurement target, and through this, pulse wave delivery time, pulse wave transmission rate, blood pressure, viscosity, etc. to calculate the heart After calculating the output, a PV plot of the heart is drawn and displayed, making it easy to check the health of the subject.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments of the present invention.

Prior to detailing the configuration of the present invention, various principles applied to the present invention will be described first.

There are invasive and non-invasive methods for assessing arterial condition. An invasive method is angiography, which is high in risk, complex in procedure, and economically expensive, and limited in clinical use.

The non-invasive method is a method of using imaging equipment such as ultrasound / magnetic resonance imaging, which has disadvantages such as relatively high economic burden and very fine measurement technology.

The present invention is to solve the shortcomings of the existing method, and the state of the heart is measured through a factor that was not considered in the prior art, that is, pulse wave and pressure measurement. This method of the present invention has several advantages, such as being simple to measure, accurate and easy to repeat. In addition, the functions of PWV, which are available as existing products, can be additionally acquired.

Pulse wave is caused by blood ejection from the heart and is a pulsation of the arterial system that occurs simultaneously with the contraction and expansion of the heart. These pulse waves are transmitted to peripheral blood vessels as factors determined by the viscoelastic properties of blood contained in blood vessels and the geometrical characteristics of arterial walls.

The output of the heart, that is, the amount of exercise of the heart, is an indicator of the degree of aging of blood vessels. If the amount of exercise of the heart is larger than a normal person, it means that the heart is sending a lot of blood flow. In other words, due to the increase in vascular resistance, the heart itself is enlarged to increase blood flow to peripheral blood vessels.

In addition, the output of the heart can be an indicator for measuring the elasticity of the heart, the more weight or age, the greater the output of the heart and the less elastic the heart.

Cardio Output [mL] = 3.33 × Weight ^{0 .75}

Vascular diseases are regarded as one of the most important diseases because early diagnosis does not appear well.

The inventors of the present invention believe that the output of the heart is directly related to the strength and elasticity of the arteries, and thus can be evaluated as an important factor indicating the state of blood vessels, and is useful for early screening of vascular diseases and for various clinical uses. With this in mind, the present invention has been completed.

1. Blood pressure measurement using pulse wave

According to the present invention, the blood ejected from the heart is circulated evenly in the human body through the arteries of the aorta, arteries, small arteries, capillaries, and then returns to the heart. The shape of the arterial waveform of circulated blood is not a steady state with no change over time, but a very irregular pulsatile waveform with periodicity due to contraction and relaxation of the heart. FIG. 1 shows major arterial vessels in the human body, and FIG. 2 shows pulsation waveforms in various arteries, that is, blood pressure waveform and velocity waveform. Normal human systolic blood pressure is about 120 mmHg and diastolic blood pressure is about 70 mmHg. The blood pressure that rises and falls with the contraction and relaxation of the heart is called pulse pressure, and the pulse pressure is about 50 mmHg. The blood pressure waveform in the aorta just above the heart is fairly irregular and uneven. The velocity waveform also shows a rapidly changing waveform. Because the walls of the blood vessels are flexible, the pressure and velocity waveforms are greatly deformed as the distance from the heart increases. For example, it can be seen in the figure that the pressure waveform and velocity waveform of the iliac artery are significantly different from those in the artery close to the heart (see FIG. 2).

The measured waveforms become several waveforms as shown in Fig. 3, and hence the same waveforms are difficult to measure, respectively. Therefore, in order to shape these waveforms, we find the lowest point of the waveform, perform linear regression analysis using the lowest point, and find the tendency for the lowest point (y = ax ² + bx + c) and subtract it from the measured data. Constant waveforms can be obtained. These constant functions can be used to obtain a normalized waveform using the Fourier Series below.

    Y = A0 + A1 * COS (1 * W0 * t) + B1 * SIN (1 * W0 * t)

         + A2 * COS (2 * W0 * t) + B2 * SIN (2 * W0 * t)

         + A3 * COS (3 * W0 * t) + B3 * SIN (3 * W0 * t)

                     :

                     :

        + AJ * COS (J * W0 * t) + BJ * SIN (J * W0 * t)

      A (J): THE COEFFICIENT OF COS (J * W0 * T)

      B (J): THE COEFFICIENT OF SIN (J * W0 * T) C

      WO: ANGULAR FREQUENCY (WO = 2 * PI / T)

The pulse wave propagation time and propagation rate can be obtained from the normalized waveform. Pulse wave propagation time is the time difference between pulse waves, and pulse wave propagation speed is the time difference between pulse waves divided by the distance between two measurement points. That is, if several pulse waves are obtained through the sensor, the pulse wave propagation time and pulse wave propagation speed can be obtained from the time difference of the waveforms using the normalized pulse waves. Increasing blood pressure decreases pulse wave propagation time, while decreasing blood pressure increases pulse wave propagation time. Therefore, if the pulse wave transmission time is known, blood pressure can be obtained by deriving a linear regression equation for blood pressure estimation through a linear regression analysis between the blood pressure and the pulse wave transmission time. This linear regression can measure blood pressure in systolic and diastolic stages with pulse wave propagation time alone. This method has the advantage that blood pressure can be easily measured without using a cuff. Since methods, algorithms, and the like for measuring blood pressure using such a linear regression equation are already well known, the detailed description thereof will be omitted. That is, linear regression analysis is a kind of statistical analysis technique. A linear regression equation for blood pressure estimation can be derived through regression analysis using measured pressure pulse wave and calculated pulse wave propagation time.

2. Viscosity of Blood

All fluids are viscous and are classified into Newtonian and non-Newtonian fluids by the relationship between shear stress and rate of change of velocity. The magnitude of the fluid viscosity also depends on the shear stress and shear rate.

In the human body, blood plays a very important role, such as supplying oxygen and nutrients, and controlling body temperature. In addition, the experimental results of blood show that the blood is yielding stress (yield stress) because the blood cells are floating in the plasma, and viscoelastic properties due to the effect of the flexible red blood cells.

Blood is known to exhibit the properties of purely viscous non-Newtonian fluid in areas with high shear rates, but yields stress in areas with very low shear rates. In other words, considering the rheological properties of blood, viscoelastic properties can be neglected in flows of relatively large diameter blood vessels such as aorta and arteries, so the blood can be treated as pure viscous non-Newtonian fluid, but the size of blood vessels constitutes blood. When flowing in capillaries with an order of magnitude approximately equal to the size of the blood cells, they should be treated as two-phase fluids with particles suspended in Newtonian fluids rather than non-Newtonian fluids.

Viscosity coefficient of blood measured by the experiment is greatly affected by the shear rate (see Fig. 4). And the viscosity coefficient decreases as the shear rate increases. To numerically analyze the viscosity problem of blood, we need a constitutive equation that can express the rheological properties of a fluid as a function of shear rate. The table below shows some of the constitutive equations and rheological values that have been reported to better simulate the rheological properties of blood.

3. Mathematical Modeling of Cardiac Output

The mathematical model of the cardiac output is represented by the voltage-resistance-current system of the cardiac output as shown in FIG. 5, and was developed using a modified Windkessel Model, which was converted to model the circulatory system. To derive the final equation for cardiac output.

The Modified Windkessel Model is an important factor in cardiovascular disease and has been used to measure the blood flow impedance parameters of blood vessels, which are fairly well known. In this model, the blood's ability to describe the recoil effect of arterial vessel walls as the proximal compliance of the aorta (C ₁ ) and the resistance of the peripheral blood system (R _s ) and the pressure waveforms propagating through the arterial vascular system in each heartbeat cycle. Inertia (L) is included. This model assumes that the virtual arterial blood system between compliant aorta and the compliant distal vessels has rigid and noncompliant characteristics to simplify mathematically.

In other words, it is assumed that the recoil effect seen in the hypothetical arterial blood system is caused by the inertia of blood in the mathematical model. It is also assumed that the frictional effect is negligibly small in this vascular system. Furthermore, the Modified Windkessel Model contains C ₂ , which is highly sensitive to cardiovascular diseases associated with hypertension, diabetes, and atherosclerosis, which affect cardiac output following changes in distal compliance (C ₂ ).

The mathematical model of the cardiac output starts from three equations derived from the Modified Windkessel Model.

Where

p ₁ (t) = blood pressure in the aorta,

Q ₁ (t) = blood flow discharged from the heart and through the peripheral blood system,

Q ₂ (t) = blood flow flowing at the distal end of the circulatory system,

Rs (t) = resistance of the peripheral blood system,

L = inertia of blood

Indicates.

Where

p ₁ (t) = blood pressure in the aorta,

Q ₁ (t) = blood flow discharged from the heart and through the peripheral blood system,

Q ₂ (t) = blood flow flowing at the distal end of the circulatory system,

C ₂ = distal compliance,

L = inertia of blood

Indicates.

Where

p ₁ (t) = blood pressure in the aorta,

Q ₁ (t) = blood flow discharged from the heart and through the peripheral blood system,

Q _IN (t) = volume of blood discharged from the left ventricle of the heart,

Q _IN (t) -Q ₁ (t) = blood flow stored in the aorta,

C ₁ = proximal compliance

Indicates.

Equation 3 describes the relationship between blood flow, Q ₂ (t) and blood pressure in the aorta, p ₁ (t). If p ₁ (t) is measured clinically assumed to be equal to the size of the proximal blood pressure of the brachial artery, Q ₁ (t) can be estimated from a hydrodynamic perspective. Using a continuous equation and a momentum equation for a rigid circular pipe, the equation for the relationship between p ₁ (t) and Q ₁ (t) can be given by the following equation.

Where

z ₁ = characteristic magnitude for the entire arterial system, τ _y : yield stress

R: radius of blood vessel, k: constant value

Indicates.

From Equation 4, the stroke volume of the left ventricle of the heart can be obtained by integrating a Q ₁ (t) curve over the heartbeat period. In other words, the area under the Q ₁ (t) curve during the period is represented by the volume of the beat. This is because Q ₁ (t) flowing through the arterial system during the heartbeat stock must be physiologically equal to the amount ejected from the left ventricle of the heart.

R _s (t) is because it is a function of Q ₂ (t), it is possible to obtain a Q ₂ (t) by substituting the equation (5) in equation (1) Generally, the pressure is the product of the flow rate and the resistance (p ₂ (t ) Is proportional to Q ₂ (t) R _s (t)). Also, the formula for C ₂ (t) is as follows.

Where

Q ₁ (t) = blood flow discharged from the heart and through the peripheral blood system,

Q ₂ (t) = blood flow flowing at the distal end of the circulatory system,

는 측정된 압력이다.

Is the measured pressure.

By combining p ₂ (t) and equation (6), C ₂ (t) can be obtained. Obtaining Q ₂ (t) and C ₂ (t) from Equation 1, these values must also satisfy Equation 2 with the same value of Q ₁ (t) and p ₁ (t). By differentiating and rearranging Equation 2, the following equation can be obtained.

By differentiating Equation 3, the following equation can be obtained.

By guessing the initial value for C ₁ (t), Q _IN (t) can be obtained from equation (8). At this time, iterative calculation method is used, which is repeatedly performed until the amount of blood flow calculated for the area under the curve of Q _IN (t) is equal to the area under the curve of Q ₁ (t).

As such, the mathematical model of cardiac output can be derived from the Modified Windkessel Model, the relationship between blood pressure and blood flow, and clinical data.

Where

p ₁ (t) = blood pressure in the aorta,

Q ₁ (t) = blood flow discharged from the heart and through the peripheral blood system,

T = heart rate cycle.

4. P-V diagram drawing

According to Frank-Starling's law, as the volume of the left ventricle increases, the muscle contractile force of the left ventricle also increases, causing the left ventricle to contract rapidly, increasing blood pressure. The left ventricle acts as the main pump of the heart. The left ventricle can determine whether there is a health problem through the relationship between the pressure and volume of the left ventricle, and the volume is extracted through the flow rate (Q). 6 is a diagram showing the correlation between the left ventricle and the aorta.

Figure 6 shows the relationship between the pressure (P) and volume (V) curve of the left ventricle. Each part is explained as follows.

2 → 3: Point 2 is where the systolic starts. In the process from point 2 to point 3, the left ventricular pressure is rapidly increasing due to contraction of the left ventricular muscle while the left ventricular volume remains constant.

3 → 4: At point 3, the pressure in the left ventricle equals the pressure in the aorta and the aortic tube begins to open. The process from point 3 to point 4 is the duration of blood flow out of the heart and drops rapidly after the left ventricular pressure reaches its maximum, closing the aortic canal at point 4. Point 4 is the end of the systole. The volume of the left ventricle is about 60 cc in adults.

4 → 1: Point 4 is where the diastolic starts. In the course from point 4 to point 1, the left ventricular volume remains constant while the left ventricular pressure decreases rapidly due to relaxation of the left ventricular muscles, usually falling to 2 mmHg in normal individuals. At point 1, the pressure in the left ventricle drops to a level similar to that in the left atrium, and the mitral tube is about to open.

1 → 2: In the process from point 1 to point 2, blood begins to enter the left ventricle from the left atrium, and the left ventricle begins to fill with blood. As the pressure rises slightly, the volume increases considerably and increases to full load. Point 2 is where the relaxation phase ends. When this series of steps is completed, the area in the curve corresponds to the day the heart does per cycle.

The present inventors have developed a device capable of monitoring a heart condition using the above principles, and the following describes a specific embodiment of the present invention capable of monitoring a heart condition using the above principles.

7 schematically shows the overall configuration of a cardiac monitoring apparatus according to an embodiment of the present invention.

As shown, the cardiac monitoring device of the present invention largely includes a sensor 10, a control device 20, and the operation and display device 30, which are connected to each other by wire.

First, the sensor 10 is provided to measure the pulse wave, it is configured to be attached to the body using at least three pressure (piezoelectric) sensor. According to the present invention, it is attached to the vicinity of the heart, the carotid artery (neck), and the radial artery (wrist).

The control device 20 is a unit for processing a signal provided from the sensor, the receiving unit 21 for receiving the pulse wave signal measured by the sensor 10, the amplifier AMP for amplifying the pulse wave signal received through the receiving unit (22), a filter 23 for removing noise included in the received pulse wave signal, an A / V converter 24 and a power source 25 for converting the analog pulse wave signal into a digital pulse wave signal.

The computing and display device 30 is provided in the form of a notebook computer, according to one embodiment of the invention. The device includes a program configured to receive and store measured pulse wave data from the control device 20, calculate predetermined cardiac output by calculating predetermined values through the series of processes described above, and calculate and display a PV plot. Doing. 9, the cardiac output calculated according to the present invention is displayed.

Hereinafter, a process of calculating the cardiac output using the apparatus shown in FIG. 7 will be described with reference to FIG. 8.

First, as illustrated in FIG. 7, pulse waves are measured through the sensor 10 attached to the heart, the carotid artery, and the wrist near the measurement target (S10).

The measured pulse wave signal is input to the control device 20 (S20) and amplified by the amplifier 22 of the control device (S30). The filter 23 inside the control device removes the noise included in the pulse wave signal to obtain a clearer signal (S40). The noise-free pulse wave signal is converted into a digital pulse wave signal through the A / D converter 24 (S50), and then sent to the operation and display device 30 to be stored (S60).

The blood pressure may be measured using pulse pressure through a program installed in the operation and display device 30 (S70). As shown in FIG. 3, after finding the lowest point of the stored digital pulse wave waveform, the waveform is obtained using the lowest point, and the pulse wave propagation time and the pulse wave propagation rate are obtained. Then, the blood pressure can be obtained through linear regression analysis. . In addition, the calculation and display device 30 calculates the cardiac output using a mathematical model of the cardiac output in consideration of the viscosity of the blood as shown in FIG. 5 (S80; see the above principle). Finally, using the values calculated through this series of procedures, the P-V diagram is obtained through the correlation between the left ventricle and the aorta (S90). The PV plot is the pressure and volume curve of the left ventricle, which cannot directly check the pressure of the left ventricle, but induces the characteristics of the normalized waveform by measuring the arterial waveform. The PV diagram of the left ventricle can be obtained by programming the correlation between the left ventricle and the algorithm by using an algorithm (S100).

9 will be described in more detail as follows.

In FIG. 9, P1, P2, Q1, and Q2 represent blood pressure and blood flow in mathematical modeling for calculating cardiac output.

The P-V plot is an important site that acts as the main pump in the heart, and correlates the pressure and volume of the left ventricle. Therefore, when the P-V plot of the experimenter is measured and compared with the data of the normal person, if there is a vascular disease related to the heart, the graph appears more distorted than the normal person. For example, when comparing the smoker's P-V plot with a normal person, the contraction rate of the pressure-volume curve is different from that of the normal person.

On the other hand, the HMS graph shows the work done by the heart. When the cardiac output of the experimenter (what the heart does during one cycle) is measured and compared with the data of the normal person, the graph becomes more distorted than the normal person when there is a vascular disease related to the heart. appear.

In addition, the blood pressure change rate dp / dt of blood pressure P and time is measured. If the experimenter increases the contraction rate of the left ventricle due to enlarged left ventricle due to heart failure, the blood pressure change rate with time tends to increase compared with the normal person.

As such, graphs such as blood pressure and blood flow of the experimenter, work done by the heart, and PV curves are compared with those of normal people, and early diagnosis and diagnosis of vascular diseases such as myocardial infarction or stroke caused by hypertension, diabetes, obesity, etc. You can judge.

As mentioned above, although this invention was demonstrated with reference to the preferred embodiment, it should be noted that this invention is not limited to the said embodiment. For example, the control device 20 and the operation and display device 30 are separately configured, and a predetermined program is installed in the operation and display device 30 to calculate PTT, PWV, blood pressure, and the like. A controller programmed to perform the procedure may be installed in the control device 20, and the arithmetic and display device 30 may be configured to only display the finally calculated PV diagram through the control device. Such modifications are also intended to be included within the scope of the invention as intended by the inventor. Therefore, this invention is limited only by the structure and equivalents of which are described in the following claim.

1 is a diagram showing the major system arteries in the human body.

2 is a view for explaining the pressure and velocity waveform measured in each artery in the human body.

3 is a diagram illustrating a process of shaping a pressure waveform using an FFT waveform.

4 is a view showing the relationship between the viscosity coefficient and shear rate of blood through the preceding researchers experiment.

5 is a view showing the modeling of the cardiac output using the Windkessel model in the present invention.

6 is a view showing the relationship between the pressure (P) and the volume (V) curve of the left ventricle.

7 is a view schematically showing the overall configuration of a cardiac monitoring apparatus according to an embodiment of the present invention and showing a place where pressure is measured.

8 is a flowchart schematically illustrating a process of obtaining a cardiac output and a P-V diagram according to an embodiment of the present invention.

9 is a diagram illustrating one embodiment of a P-V diagram calculated and displayed according to an embodiment of the present invention.

Claims (7)

A heart monitoring device used to predict vascular disease, At least one sensor attached to a predetermined part of the measurement object, A control device for processing a signal provided from the sensor, the control device receives and amplifies the pulse wave signal measured by the sensor, removes the noise contained in the signal, and converts the signal into a digital pulse wave signal With control device, Computation and display device equipped with a program configured to calculate the cardiac output using the digital pulse wave signal transmitted from the control device, calculate and display the P-V diagram of the heart And a sensor and a control device and a calculation and display device are interconnected by wires. The method of claim 1, wherein the program calculates the pulse wave propagation time (PTT) using the time difference of the waveform of the digital pulse wave, thereby calculating the pulse wave propagation rate (PWV) and blood pressure, and the blood calculated using the viscosity model Taking into account the viscosity of and using them to calculate the cardiac output through a mathematical model of cardiac output, and then using the calculated values to obtain and display a PV plot through the correlation of the left ventricle with the aorta. Cardiac monitoring device, characterized in that. The cardiac monitoring apparatus of claim 2, wherein the pulse wave propagation time is calculated by detecting a feature point of the pulse wave. The cardiac monitoring apparatus of claim 2 or 3, wherein the blood pressure is calculated through a linear regression analysis between the blood pressure and the pulse wave propagation time, and the cardiac output is calculated through the following equation.

Where p ₁ (t) = blood pressure in the aorta, Q ₁ (t) = blood flow discharged from the heart and through the peripheral blood system, Q _IN (t) = volume of blood discharged from the left ventricle of the heart, Q _IN (t) -Q ₁ (t) = blood flow stored in the aorta, C ₁ = proximal compliance, z1: characteristic size for the entire arterial system, τ _y : yield stress, R: radius of blood vessel,        k: constant value, T = heart rate cycle A heart monitoring device used to predict vascular disease, At least one sensor attached to a predetermined part of the measurement object, A control device for processing a signal provided from the sensor, the control device receives and amplifies the pulse wave signal measured by the sensor, removes the noise contained in the signal, and converts the signal into a digital pulse wave signal controller Including, The control device includes a controller programmed to calculate cardiac output using the digital pulse wave signal, calculate and display a PV plot of the heart, and transmit the calculated PV plot to an external display device connected via a wired connector. Cardiac monitoring device, characterized in that configured to display. The method according to claim 5, wherein the control unit calculates the pulse wave propagation time (PTT) by using the time difference of the waveform of the digital pulse wave, through this calculates the pulse wave propagation rate (PWV) and blood pressure, Casson viscosity model of the blood Calculate the viscosity, use them to calculate the cardiac output through a mathematical model of cardiac output, and then use the calculated values to calculate the PV plot through the correlation between the left ventricle and the aorta. Monitoring device. The cardiac monitoring apparatus of claim 6, wherein the blood pressure is calculated through a linear regression analysis between the blood pressure and the pulse wave propagation time, and the cardiac output is calculated through the following equation.

Where p ₁ (t) = blood pressure in the aorta, Q ₁ (t) = blood flow discharged from the heart and through the peripheral blood system, Q _IN (t) = volume of blood discharged from the left ventricle of the heart, Q _IN (t) -Q ₁ (t) = blood flow stored in the aorta, C ₁ = proximal compliance, z1: characteristic size for the entire arterial system, τ _y : yield stress, R: radius of blood vessel,        k: constant value, T = heart rate cycle

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