Control system for an artificial heart, artificial heart system, and method for controlling a rotary blood pump.

Abstract

This specification discloses a control system for an artificial heart. This control system comprises a rotary first pump that replaces or assists the function of the left heart of a living organism, and a rotary second pump that replaces or assists the function of the right heart of a living organism.

Description

[Technical Field]

[0001] This disclosure relates to a control system for an artificial heart, an artificial heart system, and a method for controlling a blood pump. [Background technology]

[0002] Ventricular Assist Devices (VADs) have been developed as a treatment for patients with end-stage severe heart failure. Rotary blood pumps (RBPs), including centrifugal and axial flow pumps, are more durable, smaller, and have superior antithrombotic properties compared to pulsatile blood pumps, and in recent years, rotary blood pumps have become commonly used as ventricular assist devices. The development of rotary blood pumps has made long-term implantation of left ventricular assist devices (LVADs) possible, bridging the gap to transplantation and enabling long-term home-based ventricular assist device therapy.

[0003] In particular, in patients with severe biventricular failure or those whose right heart failure worsens due to long-term use of a left ventricular assist device, there are cases where treatment with a biventricular assist device (BiVAD) by adding a right ventricular assist device (RVAD) or a total artificial heart (TAH) is indicated. Research and development using two rotating blood pumps (left and right) as a total artificial heart is also being promoted worldwide.

[0004] However, controlling two rotary blood pumps simultaneously and stably in a biventricular assist device or a complete heart replacement device, in a manner similar to that of a living heart, is an extremely difficult problem.

[0005] This disclosure was made to solve such problems, and its purpose is to automatically and stably control the flow rate of two rotary blood pumps used in a total replacement artificial heart or a biventricular assist device. [Overview of the project]

[0006] The control system according to this disclosure is a control system for an artificial heart having a rotary first pump that replaces or assists the function of the left heart of a living organism and a rotary second pump that replaces or assists the function of the right heart of a living organism, and comprises a measuring device for measuring the flow rate of the first pump, the flow rate of the second pump, left atrial pressure, and right atrial pressure, and a control device for controlling the first pump and the second pump. The left ventricular output of a living organism is represented by a first curve, which is a logarithmic function of the left atrial pressure, and the right ventricular output of a living organism is represented by a second curve, which is a logarithmic function of the right atrial pressure. The control device calculates a first coefficient corresponding to the slope of the first curve using the measured values ​​of the flow rate of the first pump and the left atrial pressure, and calculates a second coefficient corresponding to the slope of the second curve using the measured values ​​of the flow rate of the second pump and the right atrial pressure, and feedback controls the rotational speed of the first pump so that the first coefficient approaches the first target coefficient, and feedback controls the rotational speed of the second pump so that the second coefficient approaches the second target coefficient.

[0007] The artificial heart system according to this disclosure comprises a rotary first pump that replaces or assists the function of the left heart of a living organism, a rotary second pump that replaces or assists the function of the right heart of a living organism, a measuring device that measures the flow rate of the first pump, the flow rate of the second pump, left atrial pressure, and right atrial pressure, and a control device that controls the first pump and the second pump. The left ventricular output of a living organism is represented by a first curve, which is a logarithmic function of the left atrial pressure, and the right ventricular output of a living organism is represented by a second curve, which is a logarithmic function of the right atrial pressure. The control device calculates a first coefficient corresponding to the slope of the first curve using the measured flow rate of the first pump and the measured left atrial pressure, and calculates a second coefficient corresponding to the slope of the second curve using the measured flow rate of the second pump and the measured right atrial pressure, and feedback controls the rotational speed of the first pump so that the first coefficient approaches the first target coefficient, and feedback controls the rotational speed of the second pump so that the second coefficient approaches the second target coefficient. The control method according to this disclosure is a control method for a blood pump having a rotary first pump that replaces or assists the function of the left heart of a living organism and a rotary second pump that replaces or assists the function of the right heart of a living organism, and includes the steps of measuring the flow rate of the first pump, the flow rate of the second pump, left atrial pressure, and right atrial pressure, and controlling the first pump and the second pump. The left ventricular output of a living organism is represented by a first curve of the logarithmic function of left atrial pressure, and the right ventricular output of a living organism is represented by a second curve of the logarithmic function of right atrial pressure. The steps of controlling the first pump and the second pump include calculating a first coefficient corresponding to the slope of the first curve using the measured flow rate of the first pump and the measured left atrial pressure, and calculating a second coefficient corresponding to the slope of the second curve using the measured flow rate of the second pump and the measured right atrial pressure, and feedback controlling the rotational speed of the first pump so that the first coefficient approaches a first target coefficient, and feedback controlling the rotational speed of the second pump so that the second coefficient approaches a second target coefficient.

[0008] According to this disclosure, the flow rate of two rotary blood pumps used in a total replacement artificial heart or a biventricular assist device can be automatically and stably controlled. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing the overall configuration of the artificial heart system. [Figure 2] Figure 2 is a schematic diagram illustrating the blood circulation system using an artificial heart system. [Figure 3] Figure 3 shows the relationship between atrial pressure and cardiac output in a living heart. [Figure 4] Figure 4 is a functional block diagram (part 1) showing the control structure of the controller. [Figure 5] Figure 5 is an example (part 1) of experimental results of control by a controller. [Figure 6] Figure 6 shows the relationship between atrial pressure and pump flow rate in the experimental results shown in Figure 5. [Figure 7]Figure 7 is a diagram conceptually illustrating the difference between the control of the comparative example and the control of the present disclosure. [Figure 8] Figure 8 is a diagram (part 2) showing an example of experimental results of control by a controller. [Figure 9] Figure 9 is a diagram (part 3) showing an example of experimental results of control by a controller. [Figure 10] Figure 10 is a functional block diagram (part 2) showing the control structure of the controller. [Figure 11] Figure 11 shows the FSL curve, which represents left ventricular output, the FSR curve, which represents right ventricular output, and the integrated cardiac output curve FSi, all plotted on a three-dimensional coordinate system. [Figure 12] Figure 12 shows the venous return plane (VRS) and integrated cardiac output curve (FSi) represented in three-dimensional coordinates. [Figure 13] Figure 13 is a diagram (part 4) showing an example of experimental results of control by a controller. [Figure 14] Figure 14 is an example (part 5) of experimental results showing control by a controller. [Figure 15] Figure 15 shows the relationship between atrial pressure and pump flow rate in the experimental results shown in Figure 14. [Figure 16] Figure 16 is an example (part 6) of experimental results showing control by a controller. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described in detail with reference to the drawings. Parts identical or corresponding to those shown in the drawings are denoted by the same reference numerals, and their descriptions will not be repeated.

[0011] Figure 1 is a schematic diagram showing the overall configuration of an artificial heart system 1 equipped with a control system according to this embodiment. The artificial heart system 1 comprises a left pump (first pump) 10 and a right pump (second pump) 20, and a controller (control device) 100.

[0012] The left pump 10 is a rotary blood pump (RBP) that replaces the function of the left heart. The intake port of the left pump 10 is connected to the left atrium or left ventricle of the living body, and the discharge port of the left pump 10 is connected to the aorta, which is the outlet of the left ventricle of the living body.

[0013] The right pump 20 is a rotary blood pump (RBP) that replaces the function of the right heart. The intake port of the right pump 20 is connected to the right atrium or right ventricle of the living body, and the discharge port of the right pump 20 is connected to the pulmonary artery, which is the outlet of the right ventricle of the living body.

[0014] Generally, rotary blood pumps offer superior durability, miniaturization, and antithrombotic properties compared to pulsatile blood pumps. Therefore, by using rotary blood pumps for the left pump 10 and the right pump 20, as in this embodiment, it is possible to implant the left pump 10 and the right pump 20 in the patient's body for a long period of time. The structure of the left pump 10 and the right pump 20 is not particularly limited, as long as they are rotary pumps such as centrifugal pumps or axial flow pumps.

[0015] The left pump 10 has a flow rate of CO2 S A flow sensor that measures the flow rate, and left atrial pressure P L A measuring device 11 is installed which has a pressure sensor that measures CO. S ,P L A signal indicating ) is output to the controller 100.

[0016] The right pump 20 has a flow rate of CO2. P A flow sensor that measures the flow rate, and the right atrial pressure P R A measuring device 21 is installed which has a pressure sensor that measures CO. P ,P R A signal indicating ) is output to the controller 100.

[0017] Furthermore, each sensor within the measuring devices 11 and 21 may be independently positioned separately from each pump 10 and 20, rather than being attached to each pump 10 and 20.

[0018] The controller 100 includes a CPU (Central Processing Unit) 110 and a memory 120 such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The controller 100 is based on the measured values (CO S , P L , CO P , P R ) measured by the measuring devices 11, 21 to generate the commanded rotational speeds N Lcom , N Rcom , and outputs the generated commanded rotational speeds N Lcom , N Rcom to the left pump 10 and the right pump 20 respectively. Thereby, the rotational speed N L of the left pump 10 is controlled to be the commanded rotational speed N Lcom , and the rotational speed N R of the right pump 20 is controlled to be the commanded rotational speed N Rcom . The control system according to the present embodiment includes the measuring devices 11, 21 and the controller 100.

[0019] Note that FIG. 1 shows an example in which the left pump 10 and the right pump 20 are total artificial hearts (TAH) of the fully replaceable type, but the left pump 10 and the right pump 20 may be a biventricular assist device (BiVAD). In the case of a biventricular assist device (BiVAD), the suction port of the left pump 10 may be connected to the left ventricle, and the suction port of the right pump 20 may be connected to the right ventricle.

[0020] FIG. 2 is a diagram schematically showing the blood circulation system by the artificial heart system 1. The blood circulation system is classified into a systemic circulation system, a pulmonary circulation system, a left pump 10 having a left heart function, and a right pump 20 having a right heart function. The left pump 10 sucks the blood refluxed from the pulmonary circulation system and discharges it into the systemic circulation system. The right pump 20 sucks the blood refluxed from the systemic circulation system and discharges it into the pulmonary circulation system.

[0021] <Frank Starling's Law of the Heart>

[0022] The living heart has the characteristic that cardiac output increases when atrial pressure increases, which is known as Frank-Starling's Law of the Heart (hereinafter also referred to as "FS Law").

[0023] Figure 3 shows the relationship between atrial pressure (unit: mmHg) and cardiac output (unit: ml / min / kg) in a living heart. The graph on the right side of Figure 3 shows left atrial pressure P L The relationship between left ventricular output and right atrial pressure P is shown, with the graph on the left of Figure 3 being right atrial pressure P. R This shows the relationship with right ventricular output.

[0024] Left ventricular output is equal to left atrial pressure P. L It has the characteristic of increasing with increasing P. More specifically, left ventricular output follows a curve that follows the FS law, i.e., left atrial pressure P. L The curve of the logarithmic function (hereinafter referred to as "FS") L It is represented by a curve (also called a curve). FS L The curve can be expressed mathematically by the following equation (L). In equation (L), k1 and k2 are constants obtained through biological experiments, etc., and S L is FS L This is the coefficient (first coefficient) that corresponds to the slope of the curve.

[0025] Left cardiac output=S L ×{log(P L (-k1)+k2}…(L)

[0026] Right ventricular output is equal to right atrial pressure P. R It has the characteristic of increasing with increasing P. More specifically, right ventricular output follows a curve that follows the FS law, i.e., right atrial pressure P. R The curve of the logarithmic function (hereinafter referred to as "FS") R It is represented by a curve (also called a curve). FS R The curve can be expressed mathematically by the following equation (R). In equation (R), k3 and k4 are constants obtained through biological experiments, etc., and S R is FS R This is the coefficient (second coefficient) that corresponds to the slope of the curve.

[0027] Right cardiac output=S R×{log(P R (-k3)+k4}…(R)

[0028] The living heart exhibits the FS law as shown in Figure 3, which causes the left and right ventricular output to stabilize at a certain value that is approximately equal, and the left atrial pressure P L and right atrial pressure P R Each of these also reaches a stable equilibrium state at a certain value.

[0029] Note FS L Slope of the curve (coefficient S) L ) and FS R Slope of the curve (coefficient S) R ) fluctuates in response to ventricular contractility and heart rate, etc. For example, when the blood flow required throughout the body increases, such as during increased physical activity (e.g., exercise), sympathetic nervous system activity is activated, and the coefficient S L ,S R Each of these increases compared to normal. This ensures that the blood flow required by the entire body is maintained. On the other hand, in the case of heart failure, the coefficient S L ,S R Each of these decreases compared to normal levels.

[0030] <Control of the left and right RBPs (left pump 10 and right pump 20)>

[0031] In biventricular assist devices or complete heart replacement devices, controlling the regenerative braking (RBP) of the left and right hearts simultaneously, in a manner similar to that of a living heart, is an extremely difficult problem.

[0032] In a living heart, as described above, the FS law stabilizes the cardiac output of the left and right hearts to a nearly equal value, and the atrial pressures of the left and right hearts also stabilize in a state of equilibrium. However, the flow rate of an artificial heart (RBP) is highly dependent on the pressure at the RBP outlet (aortic pressure or pulmonary artery pressure) and less dependent on the pressure at the inlet (left atrial pressure or right atrial pressure). Therefore, when the RBPs of both hearts are driven simultaneously, even if the balance of RBP flow rates between the left and right hearts is initially optimized, changes in vascular resistance due to occlusion or stenosis of the aorta or pulmonary artery can easily disrupt the balance of RBP flow rates between the left and right hearts. When the balance of RBP flow rates between the left and right hearts is disrupted, the blood distribution between the systemic and pulmonary circulation becomes abnormal, raising concerns that atrial pressure may decrease, causing the RBP inlet to suction against the heart wall, or that atrial pressure may rise abnormally, leading to congestion or edema.

[0033] Therefore, in order to stably drive the left and right heart reflex points (RBPs) without causing the aforementioned problems such as suction and congestion, it is desirable to control the left and right heart RBPs as if they were following the FS law of a living heart.

[0034] To solve the above problems, the inventors of the present invention have developed a method for controlling the left and right heart RBPs (left pump 10 and right pump 20) as if they were following the FS law of a living heart. Specifically, the controller 100 according to this embodiment controls the left pump 10 and right pump 20 as if they were following the FS law of a living heart by the following method.

[0035] Controller 100 controls the flow rate of the left pump 10 (hereinafter also referred to as "left pump flow rate") CO S However, the above FS L The left pump 10 is controlled so that the relationship shown in equation (L') below always holds true, so that it changes along the curve. Similarly, the controller 100 controls the flow rate of the right pump 20 (hereinafter also referred to as "right pump flow rate") CO P However, the above FS RThe right pump 20 is controlled so that the relationship shown in equation (R') below always holds true, so that it changes along the curve.

[0036] CO S =S L ×{log(P L (-k1)+k2}…(L')

[0037] CO P =S R ×{log(P R (-k3)+k4}…(R')

[0038] Equation (L') shows the FS of a living heart. L In the above equation (L) representing the curve, "left ventricular output" is replaced with "left pump flow rate CO2". S This is a replacement for ''. Equation (R') is the FS of a living heart. R In the above equation (R) representing the curve, "right cardiac output" is replaced with "right pump flow rate CO2". P This is a replacement for "[...]".

[0039] Furthermore, by rearranging equation (L'), we obtain equation (1) below. Therefore, controlling the left pump 10 so that the relationship in equation (L') always holds is equivalent to the coefficient S calculated by equation (1) below. L This is equivalent to controlling the left pump 10 so that the coefficient S is always constant. Similarly, by rearranging equation (R'), we obtain equation (2) below. Therefore, controlling the right pump 20 so that the relationship in equation (R') always holds is equivalent to controlling the coefficient S calculated in equation (2) below. R This is equivalent to controlling the right pump 20 so that it remains constant.

[0040] S L =CO S / {log(P L (-k1) + k2) ... (1)

[0041] S R =CO P / {log(P R (-k3)+k4}…(2)

[0042] The controller 100 according to the present embodiment calculates the left pump flow rate CO S and the left atrial pressure P L by substituting the measured values into Equation (1), and calculates the coefficient S L corresponding to the slope of the FS L curve. Similarly, the controller 100 calculates the right pump flow rate CO P and the right atrial pressure P R by substituting the measured values into Equation (2), and calculates the coefficient S R corresponding to the slope of the FS R curve.

[0043] Then, the controller 100 performs feedback control on the rotational speed N L of the left pump 10 so that the coefficient S Lt (the first target coefficient) approaches the target coefficient S L , and performs feedback control on the rotational speed N R of the right pump 20 so that the coefficient S Rt (the second target coefficient) approaches the target coefficient S R . As a result, the left pump 10 and the right pump 20 can be controlled as if they have the FS law of the living heart.

[0044] FIG. 4 is a functional block diagram showing the control structure of the controller 100. The controller 100 includes a target value generation unit 101, subtraction units 102L and 102R, controllers 103L and 103R, and a coefficient calculation unit 104. The control of the controller 100 takes the form of overall negative feedback control.

[0045] The coefficient calculation unit 104 acquires the measured values of the left pump flow rate CO S , the left atrial pressure P L , the right pump flow rate CO P , and the right atrial pressure P R from the measurement devices 11 and 21, and substitutes the acquired measured values into the above-mentioned Equations (1) and (2) to calculate the coefficients S L , S R corresponding to the slopes of the FS curves, respectively.

[0046] The target value generation unit 101 obtains the target value CO of the pump flow rate t , the target value P of the left atrial pressure Lt , the target value P of the right atrial pressure Rt from the memory 102, and calculates the target coefficients S Lt , S<l Rt respectively by substituting the obtained target values into the following formulas (3) and (4).

[0047] S Lt [[ID=1{6]]= CO t / {log(P Lt - k1)+ k2}...(3)

[0048] S Rt = CO t / {log(P Rt - k3)+ k4}...(4)

[0049] Note that each target value CO t , P Lt iD=38]], P Rt is arbitrarily determined in advance by medical experts (such as doctors and nurses) and stored in the memory 12L Therefore, in this embodiment, each target value CO t , P Lt , P Rt is a fixed value.

[0050] The subtraction unit 102L calculates the difference (= S Lt ID=52]]- S L ) between the target coefficient S Lt generated by the target value generation unit 101 and the coefficient S L calculated by the coefficient calculation unit 104. The subtraction unit 102R calculates the difference (= S Rt - S R ) between the target coefficient S Rt generated by the target value generation unit 101 and the coefficient S R calculated by the coefficient calculation unit 104.

[0051] The controller 103L performs an operation with a predetermined gain on the difference (= S Lt - SID=73]] L ) calculated by the subtraction unit 102L to obtain the command rotational speed N LcomGenerates the command rotation speed N Lcom This is output to the left pump 10. This increases the rotational speed N of the left pump 10. L The commanded rotational speed N Lcom Controlled by the coefficient S of the left pump 10 L The target coefficient S Lt Controlled to the left pump flow CO S The blood is then supplied to the systemic circulatory system of the organism 2.

[0052] The controller 103R calculates the difference (=S) calculated by the subtraction unit 102R. Rt -S R ) is calculated with a predetermined gain to obtain the command rotation speed N Rcom Generates the command rotation speed N Rcom This is output to the right pump 20. This increases the rotational speed N of the right pump 20. R The commanded rotational speed N Rcom Controlled by the coefficient S of the right pump 20 R The target coefficient S Rt Controlled to the right pump flow CO P The blood is then supplied to the pulmonary circulation system of body 2.

[0053] The control mode of controllers 103L and 103R is not particularly limited. For example, the control mode of controllers 103L and 103R may be a proportional-integral controller (PI controller), a proportional-integral-derivative controller (PID controller), or a model predictive control system.

[0054] Through the feedback control described above, the left and right heart RBPs (left pump 10 and right pump 20) can be controlled as if they were following the FS law of a living heart. As a result, the flow balance of the left and right heart RBPs (left pump 10 and right pump 20) can be accurately stabilized, and the aforementioned suction and congestion can be appropriately prevented.

[0055] The inventors of the present invention conducted an experiment in which the left and right hearts of experimental animals were replaced with a left pump 10 and a right pump 20 (hereinafter also referred to as "pumps 10 and 20"), and the operation of pumps 10 and 20 was controlled by a controller 100 according to this embodiment 1.

[0056] Figure 5 shows an example of the results of the first experiment controlled by controller 100. In the first experiment, blood transfusion and blood withdrawal were performed on experimental animals while controller 100 was performing the control shown in Figure 4. In Figure 5, the horizontal axis represents time, and the vertical axis, from top to bottom, represents arterial pressure (blood pressure (systemic arterial pressure), pulmonary artery pressure), and the slope of the pump's FS curve (coefficient S). L ,S R ), pump flow rate (CO S CO P ), atrial pressure (P L ,P R ) indicates.

[0057] When the experiment begins, first, the coefficient S at the start of control is measured. L ,S R Each measured CO S , P L CO P , P R The target coefficient S is calculated using equations (1) and (2), and is also calculated at the start of control. Lt ,S Rt Each target value CO t ,P Lt ,P Rt And it is calculated using equations (3) and (4). In this embodiment, each target value CO t ,P Lt ,P Rt This is a fixed value arbitrarily set by the inventors of the present invention.

[0058] And the coefficient S L The target coefficient S Lt The rotation speed of the left pump 10 is set to N to approach it. L The coefficient S is feedback controlled, R The target coefficient S Rt The rotation speed of the right pump 20 is set to N to approach it. R This is controlled by feedback.

[0059] From the first experimental results shown in Figure 5, it can be seen that atrial pressure (P) is reduced by blood transfusion and blood withdrawal. L ,P R ) fluctuates, and consequently the pump flow rate (CO S CO P ) is also fluctuating, but the slope of the pump's FS curve (coefficient S) is changed by the repetition of the above-mentioned feedback control. L ,S R It can be seen that this value is maintained at a nearly constant level.

[0060] Figure 6 shows the atrial pressure (P) in the first experimental results shown in Figure 5. L ,P R ) and pump flow rate (CO S CO P This figure shows the relationship with (). The graph on the left side of Figure 6 shows left atrial pressure P L And the left pump flow rate CO S The relationship is shown, and the graph on the right side of Figure 6 is right atrial pressure P R and the right pump flow rate CO P This shows the relationship.

[0061] From the first experimental results shown in Figure 6, the left pump flow rate CO S However, the slope S L FS is set to a constant value L Curve (left atrial pressure P L The curve of the logarithmic function of CO2 fluctuates, and the right pump flow rate of CO2 P However, the slope S R FS is set to a constant value R Curve (right atrial pressure P R It can be seen that it fluctuates along the curve of the logarithmic function of . In other words, from the first experimental results shown in Figure 6, it can be seen that the feedback control according to this embodiment allows the left pump 10 and the right pump 20 to be controlled as if they were following the FS law of a living heart.

[0062] Furthermore, in the feedback control according to this embodiment (control of this disclosure), the slope of each FS curve of pumps 10 and 20 is a single index (coefficient S) L,S R This is represented by ). As a result, the control system according to this embodiment enables rapid and stable control from a control engineering perspective.

[0063] Figure 7 is a diagram conceptually illustrating the difference between the control of the comparative example and the control of the present disclosure. Figure 7 shows the transition of the operating point defined by atrial pressure and pump flow rate.

[0064] In the comparative example's control, when the atrial pressure fluctuates from the initial operating point, the first step is to maintain a constant pump flow rate, and then the second step is to control the operating point so that it becomes the target point on the FS curve. In this type of control, the operating point moves to the target point via an extra step (the first step), and it takes time to stabilize the operating point at the target value.

[0065] In contrast, the control method of this disclosure uses a coefficient S, which is the slope of the FS curve for each pump 10,20. L ,S R The coefficient S is continuously monitored (calculated). L ,S R The target coefficient S Lt ,S Rt Pump rotation speed N L ,N R This is controlled by feedback. This allows the operating point to be directly moved to the target point when atrial pressure fluctuates. Therefore, in the control method of this disclosure, the operating point can be stabilized to the target value more quickly than in the control method of the comparative example.

[0066] Figure 8 shows an example of the results of the second experiment controlled by the controller 100. In the second experiment, with the controller 100 performing the control shown in Figure 4, the outlet pressure of the left pump 10 was abnormally increased by increasing vascular resistance through aortic occlusion.

[0067] The left side of Figure 8 shows the results when the control method of this disclosure is applied, and the right side of Figure 8 shows the results when the control method of the comparative example is applied. Note that in the control method of the comparative example shown on the right side of Figure 8, the pump rotation speed N differs from the control method of this disclosure. L ,N R The system is designed to maintain this value at a constant level.

[0068] In the control of the comparative example, the pump rotation speed N L ,N R This pressure is maintained at a constant level. When the aorta becomes occluded while this control is in place, it has been observed that an increase in left atrial pressure, which can lead to pulmonary congestion, and a decrease in right atrial pressure, which can lead to suction, occur.

[0069] In contrast, in the control of this disclosure, even if the outlet pressure of the left pump 10 is abnormally increased due to aortic occlusion, the coefficient S L The left pump rotation speed N is maintained at the target value by feedback control. L The flow rate of the two pumps will increase automatically, so CO2 will flow through them. S CO P and atrial pressure P L ,P R This is maintained stably. As a result, the occurrence of left atrial pressure elevation and right atrial pressure decrease can be appropriately suppressed.

[0070] Figure 9 shows an example of the results of the third experiment controlled by the controller 100. In the third experiment, with the controller 100 performing the control shown in Figure 4, the outlet pressure of the right pump 20 was abnormally increased by increasing vascular resistance through pulmonary artery stenosis.

[0071] The left side of Figure 9 shows the results when the control method described in this disclosure is applied, and the right side of Figure 9 shows the results when the control method of the comparative example is applied. Note that the control method of the comparative example shown on the right side of Figure 9 differs from the control method described in this disclosure, in that the pump rotation speed N L ,N R The system is designed to maintain this value at a constant level.

[0072] In the control of the comparative example, the pump rotation speed NL ,N R This pressure is maintained at a constant level. When the pulmonary artery narrows while this control is in place, it was observed that an increase in right atrial pressure, which can cause edema, and a decrease in left atrial pressure, which can cause suction, occur. Furthermore, a significant decrease in blood pressure (systemic arterial pressure) and collapse of blood circulation were observed.

[0073] In contrast, in the control system of this disclosure, even if the outlet pressure of the right pump 20 is abnormally increased due to pulmonary artery stenosis, the coefficient S R The right pump rotation speed N is maintained at the target value by feedback control. R The flow rate of the two pumps will increase automatically, so CO2 will flow through them. S CO P and atrial pressure P L ,P R This is maintained stably. As a result, the occurrence of right atrial pressure elevation and left atrial pressure decrease can be appropriately suppressed.

[0074] In the above-described embodiment 1, the target value CO t ,P Lt ,P Rt Since it is a fixed value, the target coefficient S is the target value of the slope of the FS curve for each pump 10,20. Lt ,S Rt It is maintained at a constant value.

[0075] However, in a living heart, as shown in Figure 3 above, the slope of the left and right heart FS curves (coefficient S) changes depending on the level of physical activity. L ,S R ) are increased or decreased respectively. Due to these characteristics of the living heart, the left and right atrial pressures P L ,P R Without excessively increasing or decreasing blood flow, the necessary and sufficient blood flow required by the entire body is ensured.

[0076] Therefore, even in artificial hearts using RBP, the slope of the FS curve of the left and right RBPs of the heart (coefficient S) varies according to the level of physical activity, just as in a living heart. L ,S R It is desirable to vary each of these values.

[0077] In view of these points, the controller 100A according to this second embodiment adjusts the slope of the FS curve (coefficient S) according to the degree of variation in physical activity using the following method. L ,S R This causes fluctuations in the left and right atrial pressure P. L ,P R Without excessively increasing or decreasing the CO2 flow rate of the left and right pumps, S CO P It is possible to increase or decrease it to a physiologically appropriate level.

[0078] Figure 10 is a functional block diagram showing the control structure of controller 100A according to this embodiment 2. Controller 100A controls the controller 100 described above, adjusting the target value CO2 according to the degree of variation in physical activity. t ,P Lt ,P Rt This controller 100A adds a control structure for setting the blood volume. Specifically, the controller 100A adds a blood volume calculation unit 105, a visualization unit 106, and setting units 107 and 108 to the controller 100 described above. The other control structures and controlled objects of the controller 100A are the same as those of the controller 100 described above, so a detailed explanation will not be repeated here.

[0079] <Cyclic equilibrium theory>

[0080] Target CO2 value set by controller 100A t ,P Lt ,P Rt Before explaining the configuration method, let's first explain the cyclic equilibrium theory applied to controller 100A.

[0081] The inventors of this application have established a "circulatory equilibrium theory," a physiological theory that describes the physiological mechanism determining cardiac output and left and right atrial pressure with the minimum necessary parameters. In this circulatory equilibrium theory, the entire circulatory system is separated into a cardiac part consisting of the left and right hearts, and a vascular part consisting of the whole body (systemic circulation) and the pulmonary circulation, and the equilibrium state between the cardiac part and the vascular part is described by cardiac output CO and left atrial pressure PL and right atrial pressure P R The analysis is performed on a three-dimensional coordinate system with and as the coordinate axes.

[0082] Cardiac output CO, the amount of blood pumped from the heart to the blood vessels, is equal to the left and right atrial pressure P. L ,P R As CO increases, it increases according to the FS law and can be represented as a single curve in three-dimensional coordinates. Below, the curve representing cardiac output CO in three-dimensional coordinates will also be called the "Integrated FS cardiac output curve (FSi)". The Integrated Cardiac Output Curve FSi is calculated based on the atrial pressure P L ,P R This curve shows that cardiac output CO increases in proportion to the logarithmic function of .

[0083] Figure 11 shows FS, which indicates left ventricular output. L The curve and FS, which shows right ventricular output. R This figure shows the curve and the integrated cardiac output curve FSi represented on a three-dimensional coordinate system. L Curves and FS R The curves, while represented as curves in the two-dimensional coordinate system of Figure 3, are represented as surfaces in the three-dimensional coordinate system, as shown on the left side of Figure 11. The integrated cardiac output curve FSi is represented as FS in the three-dimensional coordinate system. L Curved surfaces and FS that represent curves R This corresponds to the intersection line with the curved surface representing the curve, and is represented by a single curve, as shown on the right side of Figure 11.

[0084] On the other hand, the amount of blood that can be sent back from the blood vessels to the heart (hereinafter referred to as "venous return CO2") V When considering the venous return CO2 (also known as the vascular portion), the left and right atria are located upstream of the blood flow in the vascular portion. V P is the left and right atrial pressure. L ,P R As it increases, it decreases, and can be represented as a single plane in three-dimensional coordinates. Below, venous return CO2 V The plane representing this in three-dimensional coordinates is also called the "venous return plane (VRS)". The venous return plane (VRS) is the atrial pressure P L ,P RWith the increase in CO2 V It is a plane formed such that the coefficient decreases.

[0085] Figure 12 shows the venous return plane (VRS) and the integrated cardiac output curve (FSi) in three-dimensional coordinates. As mentioned above, the venous return plane (VRS) is the atrial pressure P L ,P R With the increase in CO2 V While the plane is one in which the atrial pressure P decreases, the integrated cardiac output curve FSi is a plane in which the atrial pressure P decreases. L ,P R This curve shows that cardiac output CO increases with increasing P. Therefore, as shown in Figure 12, the venous return plane (VRS) and the integrated cardiac output curve (FSi) intersect at a certain point in the three-dimensional coordinate system. From the coordinates of the intersection point of the venous return plane (VRS) and the integrated cardiac output curve (FSi) (hereinafter also referred to as the "circulatory equilibrium point"), the cardiac output CO and atrial pressure P of the living organism can be determined. L ,P R Once determined, it can be analyzed or predicted.

[0086] Here, if we define the amount of blood contributing to blood circulation within the entire circulatory system of the living body as "effective circulating blood volume V", then the venous return volume CO2 V This is expressed by the following equation (C), where the effective circulating blood volume V and atrial pressure P L ,P R They are related by a linear combination equation. In equation (C), k5 to k7 are constants determined by biological experiments, etc.

[0087] CO V =V / k5-k6×P L -k7×P R …(C)

[0088] The venous return CO2 expressed by equation (C) VIn three-dimensional coordinates, this is represented as the venous return plane (VRS) mentioned above. Therefore, the venous return plane (VRS) shifts vertically in parallel on the three-dimensional coordinate system shown in Figure 12 as the effective circulating blood volume (V) increases or decreases. Specifically, when physical activity increases (when sympathetic nervous system activity increases, such as during exercise), the effective circulating blood volume (V) increases, so the venous return plane (VRS) shifts upward in parallel. On the other hand, when physical activity decreases (when sympathetic nervous system activity decreases, such as during sleep), the effective circulating blood volume (V) decreases, so the venous return plane (VRS) shifts downward in parallel.

[0089] <Target value CO based on cyclic equilibrium theory> t ,P Lt ,P Rt Settings >

[0090] Next, the target value CO2 by controller 100A shown in Figure 10 t ,P Lt ,P Rt The setting method will be explained. As mentioned above, the controller 100A sets the target value CO t ,P Lt ,P Rt The functional blocks for setting the target CO2 value include a blood volume calculation unit 105, a visualization unit 106, and setting units 107 and 108. The blood volume calculation unit 105, the visualization unit 106, and the setting units 107 and 108 utilize the circulatory equilibrium theory described above to set the target CO2 value. t ,P Lt ,P Rt Set the value to one that corresponds to your physical activity level.

[0091] The blood volume calculation unit 105 receives the CO2 flow rate from the left pump via the measuring devices 11 and 21. S , left atrial pressure P L Right pump flow rate CO P , right atrial pressure P R Each measurement value is obtained, and the effective circulating blood volume V is calculated by substituting each obtained measurement value into the following equation (5). Equation (5) is the same as "CO" in equation (C) above. V This is the result of replacing "" with "(COs+COp) / 2" and then transforming it into an equation to derive the effective circulating blood volume V.

[0092] V = {(COs + COp) / 2 + k6 × P} L +k7×P R} × k5…(5)

[0093] This allows for the real-time calculation of the effective circulating blood volume V in a living organism in which pumps 10 and 20 are implanted.

[0094] The visualization unit 106 visualizes the venous return plane VRS, which corresponds to the effective circulating blood volume V calculated by the blood volume calculation unit 105, by plotting it on a three-dimensional coordinate system. The venous return plane VRS is determined by the cardiac output CO and atrial pressure P that satisfy the following equation (6). L ,P R This is a plane that represents combinations of elements.

[0095] CO = V / k5 - k6 × P L -k7×P R …(6)

[0096] The setting unit 107 sets the optimal point OP on the venous return plane VRS visualized by the visualization unit 106. On the visualized venous return plane VRS, the target coordinate point (CO,P) is set again. L ,P R ) can be set at will. Therefore, the setting unit 107 sets the left and right atrial pressure P among the coordinate points on the venous return plane VRS. L ,P R The optimal point OP is set to the coordinate point where cardiac output CO becomes physiologically appropriate without excessively increasing or decreasing it.

[0097] The setting unit 108 sets the coordinates (CO,P) of the optimal point OP set by the setting unit 107. L ,P R ) and each target value CO t ,P Lt ,P Rt Set to this.

[0098] The above-mentioned explanation of the visualization unit 106 and setting units 107 and 108 is based on the target value CO2 based on cyclic equilibrium theory. t ,P Lt ,P RtThis conceptually describes the setting method. In practice, the visualization unit 106 and setting units 107,108 satisfy, for example, CO,P L ,P R From among multiple combinations (venous return plane VRS), the optimal combination (optimal point OP) is extracted, and the extracted combination is set to the target value CO t ,P Lt ,P Rt It can be set to that.

[0099] For example, target value CO t ,P Lt ,P Rt As an example of a setting method, the optimal point OP(CO,P) that satisfies the effective circulating blood volume V and the above equation (6) is... L ,P R The correspondence between ) is pre-mapped and stored in memory 120, and the optimal point OP(CO,P) corresponding to the effective circulating blood volume V calculated by the blood volume calculation unit 105 is stored. L ,P R The optimal point OP(CO,P) is calculated by referring to the map. L ,P R ) target value CO t ,P Lt ,P Rt It can be set to that.

[0100] Also, the target value CO2 t ,P Lt ,P Rt Another example of a setting method is the target value P. Lt ,P Rt While fixing the remaining target value CO2 within the normal range, t The CO2 may be varied according to the effective circulating blood volume (V). That is, in humans and animals, when physical activity increases due to exercise, the effective circulating blood volume (V) increases compared to the resting state, while the left and right atrial pressures remain almost constant, the cardiac output changes within a range of 2 to 3 times. In line with these biological functions, three target CO2 values ​​are set. t ,P Lt ,P Rt Among these, the target value P for left and right atrial pressure Lt ,P RtWhile fixing the remaining pump flow rate to a constant value CO2 t The above formula (6) may be used to continuously update the result.

[0101] The target value CO set by the setting unit 108 t ,P Lt ,P Rt This is the target coefficient S generated by the target value generation unit 101. Lt ,S Rt This is used for the calculation. Subsequent processing is the same as that of controller 100 described above.

[0102] By repeating the above process, the target value CO2 is reached. t ,P Lt ,P Rt This can be set according to physical activity (effective circulating blood volume V). This allows the target coefficient S, which is the target value of the slope of the FS curve for each pump 10,20, according to the body's physical activity (effective circulating blood volume V). Lt ,S Rt This allows for appropriate fluctuations in the atrial pressure P. As a result, even if the effective circulating blood volume V of the body increases or decreases during fluctuations in physical activity, the left and right atrial pressures P can be appropriately controlled. L ,P R While maintaining the CO2 flow rate of the left and right pumps within the normal range without excessively increasing or decreasing it, S CO P It is possible to increase or decrease it to a physiologically appropriate level.

[0103] <Experimental results of control using controller 100A>

[0104] The inventors of the present invention conducted first to third experiments in which the left and right ventricles of experimental animals were replaced with pumps 10 and 20, and the operation of pumps 10 and 20 was controlled by a controller 100A according to this second embodiment.

[0105] Figure 13 shows an example of the results of the first experiment controlled by controller 100A. In the first experiment, the effective circulating blood volume V was maintained at a constant level without fluid infusion or blood withdrawal in the experimental animals while controller 100A performed the control shown in Figure 10. Note that the target value CO2 shown in Figure 13 is t ,P Lt ,P Rt This is not necessarily medically appropriate.

[0106] When the controller 100A controls the effective circulating blood volume V while maintaining it at a constant level, as shown in Figure 13, the left and right pump flow rates CO S CO P , left atrial pressure P L and right atrial pressure P R Each target value CO t ,P Lt ,P Rt It was verified that it could be controlled accurately with only a small error.

[0107] Furthermore, the target value CO t ,P Lt ,P Rt As mentioned above, this is the optimal point OP on the venous return plane VRS, which is set based on the effective circulating blood volume V of the living body. Therefore, from the first experimental result, the left and right pump flow rates CO S CO P , left atrial pressure P L and right atrial pressure P R It was verified that this can be precisely controlled to the optimal point OP on the venous return plane VRS, which is set based on the effective circulating blood volume V of the living body.

[0108] Figure 14 shows an example of the results of the second experiment controlled by controller 100A. In the second experiment, with controller 100A performing the control shown in Figure 10, the increase and decrease in effective circulating blood volume V during exercise and rest of the experimental animals was simulated by increasing and decreasing the effective circulating blood volume V through fluid infusion and blood withdrawal.

[0109] Figure 15 shows the atrial pressure P in the second experimental results shown in Figure 14. L ,PR and pump flow CO S CO P This figure shows the relationship. The upper graph in Figure 15 shows left atrial pressure P. L And the left pump flow rate CO S The relationship is shown, and the lower graph in Figure 15 shows the right atrial pressure P. R and the right pump flow rate CO P This shows the relationship. "P1" and "P2" shown in Figure 15 represent left atrial pressure P L This indicates the lower and upper limits for control. Therefore, the range from the lower limit P1 to the upper limit P2 represents the left atrial pressure P L This is within the normal range. "P3" and "P4" shown in Figure 15 represent right atrial pressure P R This indicates the lower and upper limits for control. Therefore, the range from the lower limit P3 to the upper limit P4 represents the right atrial pressure P R This is within the normal range.

[0110] In Figure 14, left atrial pressure P is reduced by fluid administration. L If the value exceeds the normal range, a target coefficient S is calculated based on the effective circulating blood volume V at that time. Lt ,S Rt These are reset to increase in each case (see arrow A1). As a result, the slope of the FS curve (coefficient S) is changed as shown in Figure 15. L ,S R As the atrial pressure P increases, the "circulatory equilibrium point," which is the intersection of the venous return plane (VRS) and the integrated cardiac output curve (FSi) in three-dimensional coordinates, L ,P R The CO2 decreases and shifts toward an increase in cardiac output. As a result, the CO2 pump flow rate of both the left and right pumps increases. S CO P While increasing left atrial pressure P L This can be reduced to below the upper limit P2 and maintained within the normal range.

[0111] Furthermore, blood withdrawal can reduce left atrial pressure P L If the value falls below the normal range, a target coefficient S is calculated based on the effective circulating blood volume V at that time. Lt ,S RtThese are reset to decrease (see arrow A2). As a result, the slope of the FS curve (coefficient S) is changed as shown in Figure 15. L ,S R Because the atrial pressure P is reduced, the "circulatory equilibrium point," which is the intersection of the venous return plane (VRS) and the integrated cardiac output curve (FSi) in three-dimensional coordinates, L ,P R The CO2 increases, and cardiac output shifts toward a decrease. As a result, the CO2 pump flow rate on both sides increases. S CO P While reducing left atrial pressure P L It is possible to increase the value above the lower limit P1 and maintain it within the normal range.

[0112] As described above, in control by controller 100A, even if the effective circulating blood volume V of the body increases or decreases due to fluctuations in physical activity, the left and right atrial pressures P L ,P R While maintaining the CO2 flow rate of the left and right pumps within the normal range without excessively increasing or decreasing it, S CO P It can be automatically increased or decreased to a physiologically appropriate level.

[0113] In the second experiment shown in Figure 14, the left atrial pressure P was L At the moment when it deviates from the normal range (indicated by arrows A1 and A2 in Figure 14), three target CO values ​​are set according to the effective circulating blood volume V. t ,P Lt ,P Rt It allows for fluctuations.

[0114] However, as mentioned above, in humans and animals, when the effective circulating blood volume V fluctuates due to physical activity, the left and right atrial pressures P L ,P R While the CO2 remains almost constant, the cardiac output CO2 fluctuates. Therefore, to drive pumps 10 and 20 more physiologically, three target CO2 values ​​are required. t ,P Lt ,P Rt Among these, the target value P for left and right atrial pressure Lt ,P RtWhile fixing the remaining pump flow rate to a constant value CO2 t The target value CO is such that it satisfies equation (6) above. t It is desirable to constantly update this value to one that corresponds to the effective circulating blood volume V. To verify this point, the inventors of the present invention conducted a third experiment on control using controller 100A.

[0115] Figure 16 shows an example of the results of the third experiment controlled by controller 100A. In the third experiment, with controller 100A performing the control shown in Figure 10, the effective circulating blood volume V was increased or decreased by fluid infusion and blood withdrawal in experimental animals, and the target values ​​P of the left and right atrial pressures were set. Lt ,P Rt While fixing the value at the start of control, the effective circulating blood volume V is calculated at short intervals (for example, every few seconds), and the target value of the pump flow rate CO is set. t This was constantly updated to a value corresponding to the effective circulating blood volume V.

[0116] When the effective circulating blood volume V is increased by intravenous fluid administration, the coefficient S increases in accordance with the increase in effective circulating blood volume V, as shown in Figure 16. L ,S R While the atrial pressure P increases, L ,P R This value is maintained almost exactly as it was at the start of control.

[0117] When the effective circulating blood volume V is reduced by blood withdrawal, the coefficient S decreases in accordance with the decrease in effective circulating blood volume V, as shown in Figure 16. L ,S R While the atrial pressure P is reduced, L ,P R This value is maintained almost exactly as it was at the start of control.

[0118] Thus, even if the effective circulating blood volume V fluctuates, the target values ​​P for left and right atrial pressure remain unchanged. Lt ,P Rt While fixing it to a constant value, the target value CO t By varying the CO2 flow rate of the left and right pumps according to the effective circulating blood volume V, S CO P It can be controlled in the same way as a living organism.

[0119] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of equivalence to the claims are intended. The configurations illustrated in these embodiments and those illustrated in the variations may be combined as appropriate. [Explanation of Symbols]

[0120] 1 Artificial heart system, 2 Living organism, 10 Left pump, 11, 21 Measuring device, 20 Right pump, 100, 100A Controller, 101 Target value generation unit, 102L, 102R Subtraction unit, 103L, 103R Controller, 104 Coefficient calculation unit, 105 Blood volume calculation unit, 106 Visualization unit, 107, 108 Setting unit, 110 CPU, 120 Memory.

Claims

1. An artificial heart control system having a rotary first pump that replaces or assists the function of the left heart of a living organism, and a rotary second pump that replaces or assists the function of the right heart of the living organism, A measuring device for measuring the flow rate of the first pump, the flow rate of the second pump, left atrial pressure, and right atrial pressure, The system includes a control device for controlling the first pump and the second pump, The left ventricular output of the organism is represented by the first curve of the logarithmic function of left atrial pressure, and the right ventricular output of the organism is represented by the second curve of the logarithmic function of right atrial pressure. The control device is Using the measured flow rate of the first pump and the measured left atrial pressure, a first coefficient corresponding to the slope of the first curve is calculated, and using the measured flow rate of the second pump and the measured right atrial pressure, a second coefficient corresponding to the slope of the second curve is calculated. An artificial heart control system that provides feedback control to the rotational speed of the first pump so that the first coefficient approaches the first target coefficient, and also provides feedback control to the rotational speed of the second pump so that the second coefficient approaches the second target coefficient.

2. The control device is The flow rate measurement of the first pump is CO Ｓ The flow rate of the second pump is measured as CO Ｐ The measured value of the left atrial pressure is P Ｌ The measured value of the right atrial pressure is P Ｒ Let the first coefficient be S Ｌ Let the second coefficient be S Ｒ Let the first coefficient S be k1 to k4, where k1 to k4 are the first to fourth constants, respectively. Ｌ and the second coefficient S Ｒ These are calculated using the following formulas (1) and (2), Set the target value of the pump flow rate as CO ｔ and set the target value of the left atrial pressure as P Ｌｔ and set the target value of the right atrial pressure as P Ｒｔ and set the first target coefficient as S Ｌｔ and set the second target coefficient as S Ｒｔ When doing so, calculate the first target coefficient S Ｌｔ and the second target coefficient S Ｒｔ respectively using the following formulas (3) and (4). The first coefficient S Ｌ The first target coefficient S Ｌｔ The rotational speed of the first pump is feedback-controlled to approach the second coefficient S Ｒ The second target coefficient S Ｒｔ The control system for an artificial heart according to claim 1, wherein the rotational speed of the second pump is feedback-controlled to approach the target. S Ｌ =CO Ｓ / {log(P Ｌ -k1)+k2}…(1) S Ｒ =CO Ｐ / {log(P Ｒ --k3)+k4}…(2) S Ｌｔ =CO ｔ / {log(P Ｌｔ -k1)+k2}…(3) S Ｒｔ =CO ｔ / {log(P Ｒｔ --k3)+k4}…(4)

3. The control device is The aforementioned measurement CO Ｓ , CO Ｐ , P Ｌ , P Ｒ Using this method, the effective circulating blood volume, which is the amount of blood that contributes to blood circulation within the body, is calculated. Based on the effective circulating blood volume, the target value CO2 ｔ , P Ｌｔ , P Ｒｔ The artificial heart control system according to claim 2, wherein at least one of the following is set.

4. The control device for an artificial heart according to claim 3, wherein the control device calculates the effective circulating blood volume V using the following formula (5), where V is the effective circulating blood volume and the fifth to seventh constants are k5 to k7, respectively. V={(CO Ｓ +CO Ｐ ) / 2+6×P Ｌ +k7×P Ｒ }×k5…(5)

5. The control device satisfies the following equation (6) when the cardiac output or pump flow rate is CO. Ｌ , P Ｒ One combination is extracted from among multiple combinations, and the extracted combination is set to the target value CO ｔ , P Ｌｔ , P Ｒｔ The control system for an artificial heart according to claim 4, which is set to the following. CO=V / k5-k6×P Ｌ -k7×P Ｒ …(6)

6. The control device, in formula (6), the target value P Ｌｔ , P Ｒｔ While fixing the target value CO ｔ The artificial heart control system according to claim 5, wherein the effective circulating blood volume V is varied according to the effective circulating blood volume V.

7. The effective circulating blood volume and the target value CO2 ｔ , P Ｌｔ , P Ｒｔ It also has a memory that pre-stores the correspondence between combinations, The control device refers to the correspondence stored in the memory and determines the target value CO2 corresponding to the effective circulating blood volume. ｔ , P Ｌｔ , P Ｒｔ The control system for an artificial heart according to claim 3, which sets the parameters.

8. A rotary first pump that replaces or assists the function of the left heart of the living organism, A rotary second pump that replaces or assists the function of the right heart of the living organism, A measuring device for measuring the flow rate of the first pump, the flow rate of the second pump, left atrial pressure, and right atrial pressure, The system includes a control device for controlling the first pump and the second pump, The left ventricular output of the organism is represented by the first curve of the logarithmic function of left atrial pressure, and the right ventricular output of the organism is represented by the second curve of the logarithmic function of right atrial pressure. The control device is Using the measured flow rate of the first pump and the measured left atrial pressure, a first coefficient corresponding to the slope of the first curve is calculated, and using the measured flow rate of the second pump and the measured right atrial pressure, a second coefficient corresponding to the slope of the second curve is calculated. An artificial heart system that provides feedback control to the rotational speed of the first pump so that the first coefficient approaches the first target coefficient, and feedback control to the rotational speed of the second pump so that the second coefficient approaches the second target coefficient.

9. A control method for a rotary blood pump having a rotary first pump that replaces or assists the function of the left heart of a living organism, and a rotary second pump that replaces or assists the function of the right heart of the living organism, The steps include measuring the flow rate of the first pump, the flow rate of the second pump, the left atrial pressure, and the right atrial pressure, The steps include controlling the first pump and the second pump, The left ventricular output of the organism is represented by the first curve of the logarithmic function of left atrial pressure, and the right ventricular output of the organism is represented by the second curve of the logarithmic function of right atrial pressure. The step of controlling the first pump and the second pump is: The steps include: calculating a first coefficient corresponding to the slope of the first curve using the measured flow rate of the first pump and the measured left atrial pressure, and calculating a second coefficient corresponding to the slope of the second curve using the measured flow rate of the second pump and the measured right atrial pressure; A method for controlling a blood pump, comprising the steps of: feedback controlling the rotational speed of the first pump so that the first coefficient approaches a first target coefficient, and feedback controlling the rotational speed of the second pump so that the second coefficient approaches a second target coefficient.

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