DE2449320A1 - FULLY PLANTABLE ARTIFICIAL HEART - Google Patents

Description

Government of the United States of America Department of Health, Education, and Welfare U.S.A., Washington, D.C. 20201

Fully implantable artificial heart

The present invention relates generally to an artificial heart, and more particularly to a fully implantable artificial heart which is in a human or animal can be arranged and completely replaces the natural human or animal heart.

Of the vital organs, the heart has the most elementary Function as it simply works as a pump. The heart is one 4-chamber device consisting of two pumps called ventricles and two reservoirs called atria consists. The right heart pumps the venous blood at a low rate Pressure (20 mm Hg) to the lungs, where carbon dioxide is released and the blood is oxygenated. The left heart pumps the oxygenated High pressure blood (120 mm Hg) into the arterial system. The mean blood flow through the right and left hearts is typically 6 liters per minute. The left ventricle does roughly that quadruple work of the right ventricle. The heart's mechanical pumping power is usually between 1.5 and 4 watts. (This line

Power levels are over 10 times greater than those required for cardiac pacemakers Forces)

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The heart is an extremely complex pump that must adapt to a wide range of performance requirements in order to to bring about a blood flow adapted to the physiological requirements. To meet these requirements - between sleep and Peak load - to match, the heart must generate the required flow by changing the beat rate iZ and / or dem Ensure stroke volume.

The value and importance of the present invention will readily become: clear when one considers that a patient suffering from cardiovascular disease (the leading cause of death in the U.S.A.) is permanent or is partially dependent on a bed or a wheelchair because of the sick heart. Such a patient could undergo an operation in which the patient's heart would be completely removed and that according to the invention trained heart would be placed within the patient's body so as to replace the removed heart. After a Such an operation could be done by the patient, whose lifetime prior to the operation was extremely questionable and in any case very short. to resume an essentially normal and active life, and indeed the patient could even return to the use of the Participate in body-demanding sports and games and maintain this active life for an indefinite period of time. The present invention is designed to, in other words, extend the lifetimes of human or animal Patients extended indefinitely, that is, by patients who have a considerably shortened lifetime as a result of heart problems would have.

In the past, artificial hearts have become a complete replacement for a human or animal heart trained so that they were supplied by an energy jellyfish, worn outside the body of the user. To connect the external power source to the implanted heart an opening had to be provided in the body of the user. the Creation of the opening and the insertion of the connecting element has inconveniences, possible disturbances and for the user a risk of infection "

It is known that the natural heart during a rest period

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pumps less blood than during exercise, this being achieved by the heart increasing the frequency or the number of beats and changed the output blood size per beat. The speed of operation of known artificial hearts has been estimated at one Change of intended physical activity controlled by the natural setting of a rheostat or an equivalent element that only controls the pumping frequency changes while the blood output per beat remains substantially constant. "As a result, the operating range is more known artificial hearts are not as large and as flexible as the operating range of the natural heart, which ranges from complete rest to very vigorous exercise is enough.

The present invention aims at the disadvantages of the prior art the technique to overcome, being a fully implantable Artificial heart is provided which can be arranged within the chest cavity of a human or an animal. Another object of the invention is to provide a fully implantable heart such that it can be human or animal Heart completely replaces and automatically changes the beat frequency and the stroke volume or the output size per beat. Another object of the invention is to provide a plantable energy system that draws power from an internal storage unit and converts the energy into usable motive energy to drive the chambers of the entire heart in a controlled manner to squeeze. A control system is also provided according to the invention, which controls the flow of energy from the planted Power system to the artificial heart is regulated, whereby the controlled output energy into the blood with the correct physiological Waveforms is provided. Another object of the invention is to provide an artificial heart in such a way that this receives all returning venous and pulmonary blood at all specified requirements. The inventive fully implantable power unit provides the required energy with a current, voltage and frequency value such as it is necessary for the operation of the entire heart without generating excessive heat. The invention also aims thereby specifying a tax system, which is based on the changing

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physiological needs and the current energy requirements appeals to. The invention also aims to provide the heat distribution within the system, and also the Transfer of heat to the surrounding biological tissue and the biological fluids. The invention also provides one provide adequate flow to the pulmonary and systemic tissues without damaging the blood. The invention sees also an artificial heart, which is capable of pseudoendothelial surfaces on all of its blood-contacting surfaces Develop surfaces. Another object of the invention is to provide a whole heart which does not draw blood either from the lungs or from the lungs the vein tree and which responds fully to the returning flow. The invention also provides a system which works normally without generating unwanted noise, vibration or other side effects. The inventive Herz is designed to work with three types of internal power control systems, namely an electrical, a pneumatic or a nuclear system,

In order to achieve these and other goals, there is one main characteristic The present invention provides that a fully implantable replacement heart has four pumping chambers, two atria and has two ventricles with a unit of energy interposed therebetween. The fully implantable according to the invention Replacement heart has right and left sides, an energy converter and a heart rate control computer are also provided are. The heart according to the invention also has an energy storage pack on, wherein an energy recovery unit is also provided.

The artificial heart according to the invention resembles a natural one Hearts. It is a four-chamber pump with two atria with two large ones that form the inflow to the ventricles Valves and tricuspid pulmonary and aortic valves. Blood flows into the atri-a through quick surgical connections, which are designed so that they correspond in size and shape to the natural vessels and the artificial heart. The atriums are designed to allow large changes in the returning

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Record venous flow and respond to intrathoracic pressure. Large atrio-ventricular valves are designed to to create large flow areas to reduce the pressure drop minimize to achieve rapid filling and to minimize areas of low flow within the atria and ventricles. The ventricles are designed to produce a uniform pumping action without damaging the blood or to form stagnant flow zones. They are also arranged so that the moving internal surfaces do not come into contact with each other during the pumping cycle. This is done to eliminate potential drop-off points, and to allow living cell surfaces to be brought onto the inside surface of the pump. All with Surfaces in contact with the blood are designed in such a way that that they allow the creation of a living surface, i.e. indothelial or pseudo-indothelial surfaces. All of the components can be made from materials that do not require a living surface. The compression the ventricle is reached through a pressure plate that is connected to the outer surface of the ventricle. The ventricular ejection volume are approximately equal to those of the natural heart, so that a working heartbeat range is reached which resembles that of the natural heart. The components of the implantable heart can be replaced individually. The invention sees also the following:

The energy converter is designed such that it can be used between the blood pump arrangement or in the abdominal arrangement and provides the controlled power to actuate both the left and right hearts. The system changes converts rotary motion into linear motion within the mechanical energy converter to move each ventricle .. After the actuator is fully moved to its eject position, it is free to return to its original position. It will not return unless there is enough blood in the atria to get into the ventricles stream. The degree of fill or return of the actuator is thus entirely determined by the available blood supply in controlled the atria on a beat-by-beat basis.

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In this way, the stroke volume will automatically be zero changed to a full blow. The changes in performance as a result of the filling changes are sent to the Energy converter and the engine control electronics reported back. The engine control electronics generate a changeable electrical Input power to meet the current load conditions and to maintain a constant speed, which in turn maintains the prescribed heart rate, which is arranged by the heart control computer will. The one-piece implanted package contains the heart control computer, motor control circuits, batteries, battery charge controllers and sensing devices that monitor the amount of left or right ventricular filling.

The artificial heart according to the invention is designed in such a way that it works together with electrical or pneumatic internal power systems or an internal core power system.

The electrically powered fully implantable artificial heart has the following elements:

a) A blood pump and energy system placed in the thorax;

b) a control system, a power conditioning circuit and an energy storage unit located in the abdomen under the Diaphragm are arranged;

c) an energy absorption coil arranged under the skin, which absorbs the energy from an external transmission unit.

The electrical required to operate this system Power is transmitted through the intact skin to the implanted transformer. The energy is used directly to power the converter and / or to charge the planted ones Batteries used. If the external power source is interrupted, the system automatically switches to the internal battery power (which has a discharge capacity of up to 4 hours). The whole heart system is in the Able to meet all cardiac output size requirements, from rest to peak load_ (15 L / minute).

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It is possible to envisage the use of biological fuel cells that completely control the electrical system implantable and self-contained.

The fully implantable powered by nuclear power artificial heart replaces a thermal machine with a core heating source for the electrical energy storage unit driven heart. Hydraulic pressure generated by the machine is passed through a tube to the blood pump and its in the chest arranged control unit supplied. The heat energy source is approximately 100 grams of plutonium-238 (Pu-238) in a three-layer Metal capsule that has been proven to withstand corrosion, high shock and bursting pressures and also combustion, to prevent the radioisotope from escaping in the event of an accident.

One or two thermal machines can be used. One is a steam cycle steam engine, the other one modified Stirling cycle machine.

In the steam cycle machine system, the water alternates between the steam and liquid phases many times every second. That The basic problem of valve and sliding seal leakage occurring in conventional Ramkine machines is found in the steam cycle machine avoided as it does not use valves or sliding seals. The linear movement is achieved by means of bellows.

The steam cycle engine can be electronically controlled via any electromechanical actuator such as for example a solinoid torque motor or a piezoelectric bimorph element. Pressurizing the machine is achieved by evaporating a single drop of water or bringing it from the condenser into the boiling element.

The modified Stirling engine is built into a power source that generates hydraulic energy, which is automatic controlled actuator supplied with power. Heat is delivered through a radioisotope and in a molten salt reservoir

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saved. Liquid is with a pressure difference of pumped about 200 psig.

Ej η displacement element oscillates in a closed machine cylinder, which is heated at one end and cooled at the other. The annulus between the cylinder and the slide acts as the gas heater-regenerator and gas cooler, namely with a minimum of dead volume. Instead of the more common power piston, the cold end of the engine has an inlet and outlet check valves which allow pressure rises generated by the oscillating regenerator to be pumped Generate gas or liquid output. The sliding element is at the hot end by a bending element (Flexure held and operated from the cold end by a controllable displacement drive and a support system, which by machine pressure pulses is supplied with power.

Operation as a direct pumping system eliminates large bearing loads. The gap regenerator instead of the usual sliding element with a fixed regenerator eliminates this Sliding element gas sealing problem and greatly simplifies this miniature machine. With the sliding element drive a metal bellows seal hermetically isolates all moving bearing and sealing surfaces from the machine working gas, which results in a wide range of bearing lubrication options. The sliding element storage on hot element is a bending element that works with a stress level that is sufficiently small to have a long service life to ensure"

The pneumatic power can be supplied by a thermocompressor machine, which is a variant of the Stirling machine. The modified Stirling cycle system of the thermocompressor ~ machine converts heat directly into a pressurized gas to »and by heating and cooling the working medium is expanded in a closed circuit" the gas when it is hot and compressed "when it is cold wad work is f drawn out since the expansion work exceeds the printing work «The

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Planted thermocompressor machine converts the heat from the radioisotope source into usable by a working medium Energy around.

The pressure difference in the system is created by a single displacement piston chamber reached (hot end temperature is above 1200 ° F and cold end temperature is below 25O ° F). The implanted machine uses a regeneration that is external to the drive piston. The displacement piston moves the gas from end to end of the cylinder, through a regenerator and through a heater. When the shift piston As the gas moves into the hot end of the cylinder, the gas flowing through the regenerator is heated and heated by the hot end of the machine, increasing the gas pressure.

The system uses the pneumatic power to modulate and actuate the operation of the artificial heart. In connection a pneumatic pump actuator can be used with the other components of the artificial heart will.

The thermocompressor machine uses a thermodynamic cycle in which helium is alternately heated and cooled is used to create pressure fluctuations that can be used to drive an artificial heart. The thermocompressor machine is coupled to the blood pump through a pneumatic logic unit.

Instead of this internal implanted in the patient's abdomen Power control systems can use the artificial replacement heart according to the invention with a self-contained core drive system be equipped.

The control theory of the fully implantable artificial heart is based on the basic requirement that the total artificial heart must functionally meet the physiological requirements for supplying the body with blood. To achieve this, the tax system must ensure that

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given time the total artificial heart pumps all blood returned to it. It must be capable of any given venous return i _n the pulmonary artery and aorta at normal pressures to pump and indeed without requesting more than "If the system (body) and pulmonary venous return runs are temporarily unequally available and at normal venous pressure, so the pulmonary and system output variables must also be unequal in a corresponding manner. In addition, the control system must not include intravascular transducers or sensors, "must maximize overall system performance for any given power output level (e.g., during sleep, rest, or exercise), and must be insensitive to changes in the spatial orientation and location of the system.

An analysis of the physiological control mechanisms of the natural Heart was carried out. The physiological cardiac control systems are diverse and complex. The final result is that the natural heart can rapidly change its initial size to accommodate a wide range of physiological requirements to suffice. Basically there are intrinsic (inherent) and extrinsic (external) mechanisms of heart control. The inherent control arises from the nature of the cardiac pressure volume or the cardiac muscle fiber (stress length) relationship. This is the basis for the Frank Starling Law, which says that (in the absence of sex from outside influences) the heart has increased its output size as a result of an Input size will increase. The external control of the heart is the result of a complex neurohumoral system which the Ability to control the heart rate, the peripheral vascular tone (arteriol and venous) and the mechanical condition of the heart muscle (for example the position in the pressure-volume curve) to regulate in order to meet physiological requirements. In addition, there are external and internal mechanisms that determine the Coronary blood flow "regulates itself" so that the metabolic supply (fuel) meets the metabolic requirements of the heart is sufficient and the products of metabolism (waste) are removed. of the arterioles

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The control theory for the entire artificial heart includes both intrinsic and extrinsic mechanisms. In this In this case, the inherent control is the built-in relationship between the venous return (ventricular filling), stroke volume and Herzfate. As a result of this inherent control, the external physiological control mechanisms can still always affect the transducer. Direct input to the entire artificial heart from the central nervous system is natural unavailable. However, the cardiac output increases as a result of the peripheral neurohumoral effects of the psychological stimulus: General adrenergic levels rise when the sympathetic nervous system and adrenal medulla are activated; the (arteriole) Arteriolar tone increases to increase system pressure; the venous capacity decreases, which increases venous return. The cardiac output size is increased when the entire artificial heart responds by it the total increased return (through automatic increase in stroke volume and heart rate) to a higher systemic one Pressure pumps; more pressure-volume work is done, with the additional power required for it being available instantly is.

In short it can be said that by the inherent control by the venous return and by the large amounts of instantaneous the entire artificial heart available for this is in fact completely dependent on physiological demands is controlled. Demonstrations showed that this control theory is hemodynamically stable and completely based on the physiological one Meets requirements in multi-day trials, with a variety of intended cardiovascular conditions. Further experimental studies are required to determine the physiological effectiveness in chronic conditions to prove this theory.

There were two heart control computers to control the complete Developed with the heart. One is an analog system and the other is a digital system. Control theory uses stroke volume

as one of the main control parameters. If the pulmonary or systemic blood flow requirements increase and full stroke volumes are used, so does the heart rate automatically increased until the stroke volume decreases to less than the full stroke. When this state is reached the heart rate is decreased to balance the number of full and partially full stroke volumes. The convergence of the system is achieved because the fully implanted heart always strives to be full beat or restore and maintain near-full blown conditions in either the left or right ventricle. Any combination of conditions with altered stroke volume or heart rate in either the left or the right ventricle - which may create divergent instability (i.e. extreme tachycardia or bradycardia) could - is eliminated.

Experimental studies confirmed the computer control solution, at which the heart a) automatically increases its rate as the whole returns to either the left or right heart Blood by increasing the stroke volume up to Limit can be pumped; b) decreases the rate when the blood is returning to either the left or right heart is low and takes a very limited number of full blows to pump all of the returning blood; c) continues to operate at a given rate when the number of full beats is approximately the same as the number of incomplete beats. This control logic works on a convergence principle. The system always tends to converge to a rate which will bring the stroke volume to its fullest or near full value or at a predetermined high percentage of full stroke volume.

The main input to the heart control computer is full beat signals from both left and right ventricles. The computer continuously monitors the stroke rate and stroke volume for each beat and performs an analysis of a "s _ff nnä swar based on the immediately preceding series of Heraschlägen,

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for example from every five previous heartbeats. One of the following conditions will prevail and based on a five-heartbeat analysis produce the resulting effect:

a) When either the left or right ventricle has sufficient Number of strokes, for example four or five full strokes, the computer will determine the Increase the heart rate by, for example, five beats per minute and automatically the next row or series of beats check;

b) when the left ventricle received two or three full beats and the right ventricle received no more than three full beats, the computer will signal that that the heart rate is kept constant, for example for the next five or ten seconds;

c) if the left ventricle received no or a full beat and the right ventricle has no more than three

'picked up full strokes, so the computer signals it Heart decrease its heart rate, for example by five beats per minute, this condition being five or ten Seconds is maintained;

d) when the left ventricle received three or fewer full beats “But the right ventricle picked up four or five full beats, for example, the computer increases the rate at five beats per minute. (A particularly important part of the control logic is this automatic override.

the heart rate from the right heart, creating sensitivity to central venous conditions.)

The heart control computer (HCC) automatically regulates the heart rate over a wide range, for example from 50 to beats per minute, due to physiological Needs. Probes located in the heart but not in the ventricle generate an output signal each time, when one ventricle (left or right) is receiving enough blood to achieve a full blow. In the bloodstream or tissue, no feelers are required. According to the invention, the computer stores information related to the foregoing

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Blood pump fill history and processes it for each beat or multiple of beats (for example, all two to five seconds depending on the heart rate) in order to provide the control according to the invention described above. All numerical constants can be changed to either increase the sensitivity of the heart control computer or decrease. The above constants have proven useful in achieving a suitable level of sensitivity and response demonstrated against all normal and abnormal (drug induced) physiological conditions. The complete Heart control computers can be scaled to the size of a U.S. 10-cent piece be reduced.

A number of possible tax methods were considered in determining the tax system. These are:

a) Continuous trend method: If the stroke volume increases or decreases, the heart rate would increase or decrease on a percentage basis for each incremental change in stroke volume on a beat-by-beat basis, with both the right and left ventricles on Change to be analyzed;

b) the method of the filling rate: if changes in the filling rate and in the percentage of the stroke volume occur, the Heart rate increased or decreased;

c) the method of full stroke volume: when one of the ventricles is filled, the heart automatically goes into the Systole and expels all blood in each ventricle, or the filled ventricle expels and the other ventricle does not eject until it is completely filled; the ventricle that ejects first, however, may have a second Times do not expel, until the second ventricle is theirs Output has ended. There is a difference in synchronous and asynchronous conditions between these two limits that can be set up »

None of the above solutions require any instrumentation or sensors in the bloodstream ? they are opposite movement and any-

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not sensitive to a spatial arrangement; these concepts allow control of the rate and stroke volume with electrical, hydraulic or pneumatic logic Circuits. This allows the nuclear heart systems to work without generating electrical energy for them Steering. The fully implanted heart system used in animal experiments the simplified control concept, which monitored the condition in each ventricle based on the percentage of full beat as discussed above. If that The system has the capacity to automatically change the stroke volume and the rate, so it allows the determination of the physiological Trends and needs very precisely and with the appropriate sensitivity, so that the entire heart is automatic its rate increases, decreases or holds constant, based on physiological requirements, to a stable one Provide control system.

Satisfactory work is physiologically dependent on using surfaces that do not induce embolism or thrombosis, or the blood during pumping harm to achieve this are all with the blood surfaces coming into contact are designed in such a way that they encourage the development of living surfaces of the endothelial and allow pseudoendothelial species. All surfaces form shiny living interlayer surfaces for blood flow. Initially there was some difficulty with flow and thrombosis. Later attempts were made, however these problems are minimized by manufacturing changes. No significant adverse physiological effects occurred, such as peripheral embolism and physical damage. The leaves of the valves, both atrial and the tricuspid, remain very flexible and respond to the dynamic flow conditions without increasing changes in the pressure drop. Based on the pooled experiences, one can achieve an extensive replacement of the whole heart. To the report by the inventor of the present application entitled "Totally Implantable Nuclear Heart Assist and Artificial Heart "of the National Heart and Lung Institute (1972) is

grasslands. ■ This report is also intended for a better understanding to be included in the registration.

In addition to the above-mentioned measures according to the invention, reference is made in particular to the claims and furthermore notes that numerous features according to the invention emerge from the following description which were not previously described in the claims are covered.

Further advantages, objectives and details of the invention emerge from the description of exemplary embodiments on the basis of FIG Drawing; In the drawing: Fig. 1 shows a perspective view of an electrically operated completely planted artificial heart and its arrangement within the human body. Fig. 2 is a broken away view of a completely implantable artificial heart and its arrangement within the human body, the heart being powered by nuclear energy is operated; 3 is a broken away view of a fully implantable artificial heart with a closed one Core propulsion system, showing the arrangement in the human body.

Fig. 3 a) the artificial heart; Figure 4 is a top plan view of the fully implantable artificial heart; FIG. 5 is a view of the left side of the artificial heart according to FIG. 4; FIG. Figure 6 is a right side view of the artificial heart of Figures 4 and 5; Fig. 7 is a cross-section of the artificial heart along the line BB in Fig. 5 and the line AA in Fig. 6. Fig. .Useinandergezogene a ^a view of the entire arrangement heart. Figure 9 is a schematic block diagram of the entire electrically powered cardiac system of Figure 1. Figure 10 is a schematic block diagram of the heart rate control computer for the fully implantable artificial heart; Fig. 11 is a circuit diagram of the computer circuit; Fig. 12 is a schematic of the basic motor drive pulse circuit; Figure 13 is a schematic of the motor drive circuits; 14 is a schematic of the implantable battery power supply; 15 shows a diagram of the battery pack circuit. FIG. 16 shows a diagram of the ge ™

controlled battery charging circuit and the lower power supply circuit; Fig. 17 a series of graphs showing the relationship between venous return flow, heart rate, residual atrial volume and represent time.

In the following an embodiment of the invention will now be described with reference to the drawing, wherein this should not be understood as limiting.

In Fig. 1, the fully implantable artificial heart 101 is in place in a human's chest as a replacement for depicted a sick natural heart. The electrical Sneich unit 105 is arranged in the abdominal cavity below the diaphragm and connected to the artificial heart by means of an electric cable 102. Electrical energy from outside the Body is transmitted to an energy absorption coil 104 by an external transmission unit 103 via the skin that has remained intact, which is placed under the skin. The external transmission unit 103 can be supplied with power by batteries, these batteries (see also Fig. 9) in a vest or an attached case can be worn. By using bio fuel cells, the The need for external recharging can be avoided.

Fig. 2 shows an artificial one powered by nuclear power Cardiac system. The total artificial heart 201 is., With a Nuclear machine 203 arranged in the abdominal cavity 203 is connected by a hydraulic cable 202. The nuclear machine 203 has a Control housing 204 and a thermal energy storage unit 205. Inside the thermal energy storage unit 205 there is a plutonium fuel capsule 208. A vacuum foil insulation 207 is between the control housing 204 and the thermal energy storage unit 205 arranged.

3 shows the fully implantable artificial heart 301 with a self-contained core propulsion system 302. As can be seen, this solution eliminates the need for a

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- 18 energy sources arranged in the abdomen.

The total artificial heart 1 has - cf. FIGS. 4 to 8 in principle a left atrium 60, a left atro-ventricular (A-V) valve plate 7, a left ventricle 61, an energy converter 54, a right ventricle 51, a right A-V valve plate 55 and a right atrium 50 (see FIG. 7).

The left atrium 60 has a flexible cup-shaped bladder and an open branch 62 to receive arterial return from the lungs. The open end of the bladder faces Center of the artificial heart 1 and forms a complete envelope around the outer surface of the left A-V valve plate 7.

The left A-V valve plate7 is a rigid circular disc, which has a plurality of longitudinal openings 63 (see FIG. 8). Each longitudinal opening 63 has flexible flaps the A-V valves 64 covered. Metal stiffeners are in the A-V valves 64 are embedded, which are hinged to the inner surface of the left A-V valve plate 7. The A-V Valves 64 have essentially the same shape as the longitudinal openings 63 and cover the longitudinal openings in their closed state Completely.

The left ventricle 61 also has a flexible cup-shaped Bladder and an open branch 65 to provide arterial flow to the body. The open end of the bladder faces outwards from the center of the artificial heart 1 and forms a complete envelope around the inner surface of the left A-V valve plate 7 around. A tricuspid valve 66 is disposed within the open end of the junction 65. The tricuspid valve 6 6 has three slits or channels in its surface for blood to flow through (see Fig. 8). The left ventricular casing 3 is sleeve-shaped so as to accommodate the left ventricle 61, and has an outer thread Outer end 67 on. The externally threaded outer end fits into an internally threaded O-shaped left atrial clamping ring 5 in "

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The left atrial clamping ring 5 fits over the left atrium Co and, after screwing onto the left ventricle housing 3, attaches the left A-V valve plate 7 between the left one Atrium 60 and left ventricle 61. The unit between the ventricle housing and the atrial clamping ring is fixed by an atrium disk 4.

The left ventricle housing 3 is like the right ventricle housing 2 formed with an opening in its underside. A tubular CO 2 puncture housing43 is in the opening in the Ventricular housing is inserted and a self-sealing disc 53 is inserted therein. This arrangement allows a hyperdermal needle (syringe) or similar device comes into contact with the interior of the ventricle, creating a Means for the input and the delivery of fluids is created. A disc 45 and a cover 44 are used for Completing the CO 2 puncture housing 43 and the self-sealing Disk 53 (see Fig. 7). With the appropriate lower 3/4 of the outside surface of the inside of the left ventricle 61 and right ventricle 51 are connected to pressure plate assemblies 70 and 10, respectively.

An energy converter 54 is in the center of the artificial heart arranged. The energy converter 54 wandel * - electrical energy into mechanical and is used to actuate a suitable drive device / which in turn moves the pressure or compression plates 70 and 10 outward. The outward one Movement of the pressure plates need not occur simultaneously, as shown in Fig. 7, where the right ventricle 2 passes through the outward movement of the right pressure plate 10 is compressed, while the left ventricle 61 and left compression plate 70 are shown in their uncompressed state are. When the pressure plate assembly is pushed outwards. are · and the ventricles have been compressed, becomes a return spring 52 or a similar device is used to set the printing plate assemblies to be returned to their original position.

The energy converter 54 is within the left ventricular housing

3 and the right ventricle housing 2. The housings are attached to one another by means of a "V ^rt" bracket 11. The "V" bracket has two jaws which are pivotally connected to a third connecting section by means of hinges 12, 12 and 13, 13 and dowel pins 16. Die open ends of the jaws can be brought together and tightened by means of angle brackets 15 and nut 14 (see FIG. 5).

In the energy converter, electrical energy is obtained from either an electrical energy storage unit or a core machine which is arranged in the abdominal cavity, and the energy is supplied via a multi-core wire 23. The multi-core wire 23 is enclosed in an insulated sleeve 17 and is connected to the energy converter 54 via corresponding openings in each of the "V" brackets 11, and the Bottom of the connected left ventricle housing 3 and right ventricle housing 2 (see FIG. 7) in connection. A sliding sleeve 22 is arranged in the opening in the "V" bracket 11 and serves as a sleeve for the multi-core wire 23 running through it. Shortly before it enters the sliding sleeve 22, the multi-core wire runs Wire 23 through a dome-shaped clamping sleeve 21, which covers the opening in the "V" bracket 11.

Of course, using a biofuel cell or using an artificial heart would include an enclosed nuclear power source the need for the separate electrical energy storage unit of the nuclear power machine and that Avoid connecting cables.

The invention also provides that the right side of the artificial Heart 1 is similar to the left side with the exception that. instead of a single junction 62 as with that left atrium 60, the right atrium has a dual branch. This dual branch has a branch 68 and another Branch 69, with branch 68 receiving the venous return flow from the trunk, while the other branch 69 receives the venous return flow absorbs from the head. The right atrium can also be a single one

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Have influx similar to that like this for the left atrium 60 is shown.

The right ventricle 51, like the left ventricle 61, has a simple junction 71. The junction 71 supplies venous Flow to the lungs and also has a three-channel tricuspid valve.

The tricuspid valves are. In a metallic cylindrical Tricuspid valve housing 2 5, 25 accommodated, which are arranged at the ends of the branches 65 and 71. The tricuspid valve body 25, 25 are attached to the branches by a spacer ring 26 and a clamping ring 27 (see FIG. 5). All Valves of the artificial heart are interchangeable and can be of different types, for example for disc, ball, Valve and tricuspid design include.

At the open ends of the branches 62, 68 and 69 are metallic cylindrical coupling rings 33 attached over the outer ends the coupling rings 35 and the tricuspid valve housing 25, 25 are cylindrical dacron-flocked metallic quick-connect connections 30 arranged. The quick connections 30 have multi-fingered retaining rings 28 which attach the quick connections the tricuspid valve housings 25, 25 or the coupling rings 33. On the outer surface of the quick connections 30 spikes 34 that can be grasped by the tissue are provided.

Tubular elbow adapters 31 may be disposed within quick surgical connectors 30 if so is required to improve the tissue connection. ^ A protective ring 32 surrounds the outer diameter of the end of the elbow adapter, which is not arranged within the surgical cutting connections 30 (see FIG. 5). The artificial one The heart can also be connected to the appropriate flow channels of the body via connectors which are connected to the Fabrics are sewn.

The atria, ventricles and A-V valves can be made from Silastic or Polyurethane or a similar material. the

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Ventricular housing, the atrial clamping rings, the "V" -clamping arrangement, The surgical quick connectors and the tricuspid valve housings can be made of stainless steel or a be made similar material. The A-V valve plates can be made of any suitable material. All surfaces that come into contact with blood are with Dacron or equivalent material provided to allow the development of a living surface, i.e. endothelial or to promote pseudoendotheli.al surfaces.

The basic whole heart assembly procedure involves "the following steps:

1) The tricuspid valve housings are attached to the left and right ventricle clamped and connected to it;

2) quick connect surgical adapter rings are connected to the left and right atrial entrances;

3) the right and left ventricles are placed in their respective metal housings;

4) the right and left A-V valves will be on the corresponding Ventricles arranged?

5) the right and left atria are placed and the atria clamp rings are tightened.

The following is an exemplary embodiment in its inventive Heart rate control computer described. The heart rate control computer is shown schematically in FIG. 10 and is in FIG included in the implantable electronics package and on a Circuit board formed.

The heart rate control computer regulates the heart rate over a range of 50 to 120 beats per minute according to the invention according to signals which the ventricular Show filling. According to the invention, a sensor is provided in order to generate an output signal & l every time a ventricle

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receives enough blood to make her 95% or more of her Fill up capacity. The computer stores and processes this information regarding the recent blood pump fill history this information to generate one of the following commands:

1) The computer commands a 5 beats per minute increase in rate "when the left or right side receives 5 full indications out" of 5 operations.

2) The computer commands a 5 beats per minute decrease in rate if the rate has not changed for 10 seconds and the left side has at most one full indication or reading of 5.

3) The computer commands that there is no change in heart rate if neither the increase nor the decrease criteria are fulfilled.

After the start of the computer cycle - see the block diagram of Fig. 10 - when a fill detector output exceeds the threshold of the corresponding fill pulse generator transmit an impvls to the filling counter. This always occurs when the corresponding ventricle is at least is 95% full.

The counter reading detectors determine whether one of the filling counters has reached a counter reading of 5, or whether the counter reading on the left is less than 2. When the reset pulse occurs, the rate change calculation logic circuits determine whether a Rate change is required. When every 5 count detectors has an output, the rate change calculator sends a guessing impulse to increase the heart rate memory value in the computer increased by an amount corresponding to about 5 beats per minute, \ 7ann the 0 orΊ counter reading detector one Output variable and the 10 second delay pulse generator has no output, the rate change calculator sends a rate decrease pulse that increases the stored computer heart rate value by 5 beats per minute

609810,

reduced. The 10 second delay pulse generator has then an output when either a rate increase or a decrease pulse is sent within the last 10 seconds became. Therefore, after a heart rate change, the heart rate will not decrease for at least 10 seconds.

In addition to the measures according to the invention mentioned in the preceding paragraph, the invention also provides that the value in the computer heart rate memory determines the speed at which the motor drive control circuits attempt to drive the motor in the energy converter to drive. The actual heart rate is proportional to the engine speed or speed. The rate control error generator therefore compares the engine speed computer output to the computer heart rate memory to determine the error signal input for the motor drive control circuits to be determined. The engine speed signal is also used in the heart rate counter to operate. When the heart rate counter reaches a count of 5 beats, the reset pulse generator a reset pulse is generated. This resets all counters and triggers the rate change calculator outputs. The computer cycle then starts again.

Since now operational amplifiers working with extremely low power are available, the decision was made to use an analog instead of a digital circuit in the rate computer. This circuit is shown in FIG.

In the fill pulse generators, linear amplifiers N1 and N2 amplify the signals from the stress fill detectors. Their output variables are applied to threshold amplifiers N3 and N4. The gains of amplifiers N1 and N2 must first be adjusted to compensate for differences in strain gauge sensitivity. Then the right and left threshold values, as determined by the voltage divider, must be set in such a way that filling pulses are generated at the point where the blood pump is 95% full ) consist of HS ₁ , W7 as well as N9 and N6, N8 and N 10 and they generate filling pulse generator output variables

with constant width for operating the filling counter.

The filling counters are simply analog integrators (N11 and N12). The integrators operate the threshold value circuits (N21, N22 and N23), which perform the counter detector functions. The logical operations of the rate change calculator are carried out by the diode driver amplifiers N24 and N25.

The 10 second delay generator is a monostable multivibrator (N30 to N33) that is reset by transistor Q5 every time it receives an input, regardless of whether a count is complete or not. The 10 millisecond delay multivibrator associated with this circuit (N26, N27 and N2 8) eliminates a "racing condition" in the logic circuit.

The computer heart rate storage is done by the analog integrator N29 performed, which also has limiting diodes to control the extreme values of the heart rate. For manual adjustment the heart rate as it is determined by this circuit Provision made. The manual rate is obtained either by actuating a toggle switch in the TestpunktkaF.Len, or by Operation of an internal magnetic switch by means of a large one Magnets outside the electronics package.

The rate control error generation is done by a differential amplifier N34 carried out, which is the output variable of the heart rate memory compares with the engine speed signal and operates the drive pulse generator.

The heart rate counter is an analog integrator N13, which accordingly the engine speed signal works. When the integrator indicates that the time of 5 heartbeats has passed, it fires Threshold amplifier N14 and triggers the 15 msec delay level vibrator (N15, NI6 and N17). This multivibrator triggers the output of the logic circuit and then ignites the 60 msec monostable multivibrator (N18, N19 and N20), which the Reset transistors that drive 3 integration counters. The 15 msec

603018/0419

The multivibrator is designed so that it oscillates freely when its input variable remains high, see that in the heart rate counter and the reset circuit do not interlock can.

The invention provides that in the basic motor drive control loop the phase of the moving rotor is indicated by hall effect device signals. These signals are through the drive or driver pulse generator is converted into drive or driver pulses of the appropriate phase, the Driver pulse widths can be controlled by the error signal from the rate counter. These pulses are then used in the motor drive circuits reinforced and used to drive the two phase motor windings. One proportional to the engine speed made signal is generated by circuits in the driver pulse generator. This signal is according to the invention with compared to the desired engine speed signal in the rate computer to generate the rate control error signal.

Referring to Figure 12, there is shown the circuit associated with the generation of the motor drive pulses. Generate according to the invention Amplifiers N3 and N4 amplified Hall signals of the desired amplitude and the desired direct current level. The resistances R1 through R8 are set to compensate for differences in individual Hall device characteristics, as shown in FIG the drawing is indicated by the comments. Ordinary mode changes in reverb device output sizes due to electrical noise, bias changes and thermal changes are caused by the input circuit of these amplifiers balanced.

The amplifiers N5 and K6 are inverters with a gain of one. Since the Hall devices according to the invention are arranged on the motor stator, they are out of phase by 90 ° with respect to one another Generating rotor position signals generates the addition the inverter signals with all 4 phase shifts by 90 °.

The phases of the 4 generated Hall signals generally hit

609818/0419

does not coincide with the optimal phases for the motor drive pulses. However, since these signals are almost sinusoidal, they can simply be combined in weighted resistance adders to produce 4 signals with the desired phases. The resistors in this case are the 16k ß and 3OkS resistor connections to the B, B, Ä and A test points of the drawing. The signals at these test points are again almost sinusoidal and have the phases required for the motor drive pulses.

The actual drive pulses are generated in the threshold amplifiers N7 to N1O generated. At the negative input of N7, for example, 3 signals are added according to the invention:

1) The Hall signal, which has a negative maximum at the time when the phase Α pulse should occur;

2) a positive going full wave rectified signal, which is formed from the phase B and B Hall signals;

3) the AC rate control error signal from the computer.

The resulting waveform has a negative triangular tip at the desired phase for the A drive pulse. A positive output pulse is generated during the time when this signal is below the amplifier threshold. The pulse width increases as the rate control error signal is made more negative. Amplifiers N8, N9 and N10 operate in a similar manner Way to generate A, B and B drive pulses. The inventive method produces a smooth, to a reasonable extent linear change in the drive pulse width with control error signal for drive pulse widths up to 130 °, so that the The feedback gain of the control loop is almost constant over the range of the normally required drive pulse widths is.

In accordance with the invention, there are motor drive circuits shown in FIG from 2 parts:

1) The power amplifier ^ which the 2-phase motor ^
drive winding;

2) the analog circuits, which calculate the motor current and the motor speed from the motor input signals.

The drive or driver amplifiers are of conventional design except that the amount of drive current available is varied in proportion to the peak motor current required as determined by the motor current calculation circuit
is. This drive level signal is applied to pin 2 of amplifiers N12 to N15 via 150kA resistors, and it determines the output amplitude of these amplifiers. The these amplifiers
The following power output stages are simply switched on or off by the amplifier output pulses, whereby almost
the full battery voltage (+ 14 V nominal) is applied to the drive motor winding for a period of time that
equal to the input pulse width from the drive pulse generator
is. The advantage of current level drive control is that, and therefore, less current is drawn from transistors Q5 through Q8 when low output currents are required
these amplifiers maintain reasonable efficiency at low drive levels.

The current calculation circuit simply amplifies the voltage drop across the 0.0300 restores in series with each motor winding, in balanced differential amplifiers (N6 and
N10). These amplifier outputs are then inverted in amplifiers N5 and N9 so that both positive and negative representations of each current pulse are available. The outputs of these 4 amplifiers are applied in accordance with the invention to a 4-phase full wave peak detector, the output of which is smoothed in a filter amplifier N4 to give a DC signal which controls the driver amplifier output performance.

The voltage applied to the motor winding is also balanced by (Push-pull) differential amplifiers N3 and N11 obtained. These signals are in RC circuits with the current waveforms

of N5 and N9 are combined, the result being amplified in amplifiers N2 and N8 to reproduce the motor lock emf to obtain. Because the motor blocking EMF (motor back EMF) is proportional to the motor speed, a signal with DC level properties for the motor speed is obtained from the blocking emf signal in a 4-phase detector, with the required waveform inversions being performed by amplifiers N1 and N7 · ^ will. The resulting signal is fed to the rate computer for comparison with the desired engine speed signal, and the resulting rate control error signal is used to control the drive pulse width.

The implantable battery power supply formed in accordance with the invention is shown schematically in Figure 14 and receives its input power from the implanted secondary coil a transformer working with intact skin. A controllable rectifier circuit converts this AC power into direct current at a voltage that is used both to charge the battery pack and to operate the motor control circuits sufficient. The battery pack is connected in parallel with the load, as shown, so that it can handle both the ripple current from the charger and absorbs the alternating current fluctuations in the load current.

The battery control circuits receive information from each cell of the battery pack to control the charge output.

If at any time the charge level of the battery pack drops below an optimum value, the control circuit generates maximum available power to charge the pack in the shortest possible interval. If any or If several cells in the battery pack reach their fully charged state, the control circuit terminates the rapid charging and returns to a normal slow charge mode.

If the power output is not available, for example then, when the main transformer is disconnected, power is delivered through the implanted battery pack in order to

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to operate the ladder. Sufficient capacity is provided to hold approximately 3 to 4 of the entire cardiac device Operate for hours. If the AC power is no longer switched on before the battery is discharged, then stop the battery control circuit discharges the battery when any cell of the battery pack has reached a cell voltage of approximately 0.7V is discharged. This protects the battery pack from over-discharging and from possible cell damage.

The battery output current provides power directly to the motor drive circuit output stages and also supplies the low-power voltage supply, which provides regulated voltages for the Low power circuitry in the motor drive control and rate computer generated.

The battery pack circuit of the present invention is shown in FIG shown. The battery cells are special 4 Ah nickel-cadmium cells manufactured by General Electric. Own the cells a third terminal connected to a sealed stainless steel housing which senses the battery state of charge. When the third-terminal-to-negative-terminal-voltage is approximate 0.3 V on an 18GO load increases, the cell is complete loaded. Amplifiers N2 through N12 sense the third terminals of cells BT1 through BT11 in a corresponding manner, and if so Any (or more) of the third terminal voltages reaches 0.3V, the corresponding amplifier pulls the voltage on the common output bus to a high voltage. This in turn pulls the charge control signal upwards as permitted by the N13 slow charge control amplifier. this has with the result that the battery charger goes into the slow charge mode (buffer charge mode).

The buffer charge amplifier circuit amplifies and averages the Voltage drop across the 0.020JL battery current sensing resistor a mean or average time constant of about 100 seconds, so that battery current fluctuations within a single heartbeat. The initial

609818/0419

The size of the amplifier N13 is then for small positive Average currents proportional to the average battery current. If the battery charges quickly, so If the output is high, the series output diode is off and affects the charge control signal not which is low during that time. When the batteries are charged and one or more of the output variables the amplifier N2 to N12 are high, the charge signal voltage rises and the series output diode N13 switches and the N13 output voltage pulls the charge signal down again until the desired average trickle charge is reached, as can be done by setting the resistors R2 and R3 is determined.

If the load input power is removed, so must the battery will deliver the full charge current and begin to discharge. When the charging input power is not turned on again before one or more cell voltages has dropped to approximately 0.7 volts, then the power on / off signal becomes increase and shutdown the system until the charge input power is provided again.

In battery operation with the charging power switched off, the series chain of transistors Q1, Q2, Q3, Q5, Q7, Q9, Q11, Q13, Q15, Q17, OJ 9 and Q21 turned on, causing the negative terminal of amplifier N1 is pulled high and a low power on / off signal level which keeps the low power voltage supply turned on. If any of the cell voltages drops below approximately 0.7 volts, the bias for one of the transistors in the chain is lost, the Chain switches itself off, the power on / off signal level increases on, the preload for Q1 is lost, and the chain cannot be switched on again until the power on / off Signal for a high signal on the AC power on signal is lowered. (The AC power on signal then becomes pulled up when the charge input power is turned on.)

The bias for the chain transistors is provided by transistors. Q4, Q6, Q8, Q1O, Q12, OJ 4, OJ 6, Oj 8, Q20 and Q22 generated,

60S818 / Ö41S

where the base-emitter voltage of these transistors is the The exception is cell BT1 and transistor Q2, which is a direct input from cell BT1 biased chain transistor is. In this case it is the base-emitter voltage of Q2 + the small saturation voltage of Q1 which is the cut-off voltage of cell BT1 certainly.

A magnetic tongue or read switch S1 can also be used to manually switch off the system or but the external DC circuit breaker can be opened. In the latter case, the power on / off signal remains low.

The controlled battery charging circuit according to the invention shown in FIG. 16 is basically a controlled bridge rectifier, with CR1, CR2 and Q1 as well as Q2 being the high-current elements are. The duty cycle of Q1 and Q2 is controlled to give the desired charging current. The input frequency from Main transformer is 400 Hz.

Due to the high leakage inductance of this transformer, the power source is a high impedance source and the Transformer output voltage rises to 40 or 50 V peaks during the portion of the cycle where Q1 and Q2 are turned off. When Q1 and Q2 are each on for a full 180 degrees, the output wave from the transformer is essentially a square wave (although the input is a sine wave with a large amplitude).

The invention also contemplates the use of voltage doubler rectifier circuits with low power to provide the +21 V and -6 V (nominal) power for the control circuit in this unit and create the battery pack circuits. The +21 V also provide the AC power ON signal by turning on transistor Q7 for the battery pack. Diode-capacitor pulse shaping circuits produce 30% duty cycle sawtooth waves, which are compared to the charge control signal from the battery pack to determine the time percentage determine to fire N5 and N6. One small «. Size of input

- 33 -.

transformer wave is the charge control signal through 3.3 MO resistors is added to ensure that N5 and N6 turn off during alternate half cycles of the input shaft regardless of the charge control signal level. The amplifiers N5 and N6 operate the power stages which fire the transistors Q1 and Q2.

It has been found that a pair of triacs can replace elements Q2, Q4 and Q1, Q2, resulting in better reliability results. (Q1 and Q2 are germanium power transistors.)

The low-power voltage supply according to the invention is also shown in FIG. To generate the bias voltages with low power required for the engine and the computer attitude required will be the battery voltage (+14 volts nominal) first adjusted to +11.0 volts by amplifier N1 and pass transistor Q 10. the Zener diode CR5 creates a stable reference.

+5 volt power is taken directly from the +11 volt through regulating amplifier N2 received.

A 10 kHz astable multivibrator (N3 and N4) with power output stages Q11, Q12 and Q13 as well as Q14 run through the + 11VoIt and +5 volt regulators and operates voltage doubler rectifier circuits to generate the -10 volts and +20 volt voltage. Supplies.

When the battery voltage is in the normal range, the low power voltages are within one Percent or less stable. The absolute value of these voltages is not critical, but the +11 volts will usually be set to within 0.1 volts of nominal. Adjustments to the rate computer timing circuits are made no until the +11 volts are set since the computer threshold and timing settings are somewhat critical. Before the charge control circuits the system switch off, the discharged battery voltage

609818/0419

drop low enough that the +11 volts are out of regulation come out. This often creates abnormal behavior the computer, which is a warning and indicates that the battery is nearly discharged.

The power supply to the system is then cut off when the power on / off signal from the charge control circuits goes high and the series transistor switch (QB and Q9) between the battery and the +11 volt regulator is switched off will. The low power voltages drop to zero and the power transistors driving the motor lose them Bias and turn off, leaving the only one remaining Battery load the leak in the charging power transistors Q1 and Q2 and the a few milli-amperes Charge control circuits of the battery pack are. (Reduced the use of triacs in the charger - as described above significantly the remaining battery power load. )

In operation, the electrical energy is sent to an external transmission unit 103 transmitted by batteries, soft in a case or a vest (see. Fig. 1) are worn. the electrical energy is then according to ^ the invention of the external transmission unit 103 via the intact skin transmitted to an energy collection coil 104 which is implanted just below the skin. Then the electrical one runs Energy to an electrical energy storage unit 105, where it finally goes to the energy converter of the artificial heart is transmitted.

The energy converter according to the invention converts the electrical energy into mechanical energy by means of an electric motor um, which operates any suitable mechanical drive means. In the preferred embodiment, the electric drives Motor cam links through a series of reduction gears. The cam members are twisted to their upper point and they push the compression plate assembly outward, compressing the ventricles. This squeezing the

603318/0419

The ventricle creates the actual pumping action of the blood. When the cam continues to twist past its high point the cam surface loses contact with the pressure plate assembly / which is now in its original position can return by return springs or similar devices. However, the compression plate will only return when blood is available in the atria to flow into the ventricles. According to the invention is thus the degree of filling or the Return the compression plate fully through the available blood supply in the atria on a beat-by-beat basis controlled.

When using a core power source as shown in Fig. 2 is, energy in the form of heat is converted into electrical energy in the thermal energy storage unit 205. Then the electrical energy is transported to the energy converter of the artificial heart, while the electrical energy is converted into mechanical energy in the manner described above. The same basic procedure is used when making an electrical Heart is used with a built-in core propulsion system.

In a typical cycle, blood will be CO2-carrying on the right Delivered atrium or atrium. From the right atrium, blood flows through the right A-V valves into the right ventricle. if the right ventricle is compressed by the outward movement of the right pressure plate assembly, so will the blood contained in it is pushed outside or pumped to the lungs, where the C02 is released and the blood is oxygenated.

The oxygenated blood is then transported back to the left atrium or atrium. The oxygenated one runs from the left atrium Blood through the left A-V valves into the left ventricle. if the left ventricle is compressed by the outward movement of the left compression plate assembly, see above the oxygenated blood it contains is driven out or pumped into the arterial system. The cycle begins then all over again.

609818/0419

Blowing through the A-V valve and the resulting backflow of the blood from the ventricles to the atria (atria) during pumping is carried out according to the invention by metallic Prevents struts that are embedded in the flexible flaps or A-V valves.

If the ventricular blood volume changes during pumping, must., also the internal volume of air between the ventricles change. This is achieved through a flexible bag made from Silastic or a similar material, and which is connected to the outside of the metallic ventricle housing by a clamp connection. This bag also makes a body fluid seal for the electric motor.

As mentioned above, the left and right needs pumping Ventricle does not occur simultaneously and is actually also regulated by the heart rate control computer. Operational According to the invention, the computer response to a decrease in inlet blood flow becomes completely within a single one Beat interval recorded by decreased ventricular filling, but while increasing the inlet flow through one or more of the following three mechanisms must be included:

1) A 10% increase in ventricular filling can occur within of a single beat (assuming the inflation sensor trigger is set to 90% of the ventricular volume).

2) The computer can increase the heart rate, but within the limit rate of change of 4.25 beats per minute / Blow.

3) When the ability of the above two mechanisms is exceeded, or during a speed change transition, must be the excess of inflow-outflow in the atria are accumulated.

If there is a surge that will eventually destroy the atrial reservoir

S09818 / 0419

If capacity is exceeded, the inevitable consequence is an increase in atrial pressure, resulting in an increase in vena-caval or pulmonary venous pressure means; any of these increases in pressure should be avoided. The most critical situation therefore results from a gradual increase in blood flow, which exceeds the 10% excess ventricular capacity. The atria should be designed to accommodate reasonable changes in flow that occur frequently. The following analysis provides a method for predicting the required atrial capacity necessary to achieve a given Record a step change in the venous return flow without creating excessive atrial pressures.

When the blood return to the heart is increasing at a greater rate, than the computer can accommodate by increasing the heart rate (such as a step increase in the venous return) then must blood will continue to accumulate in the atria until the rate increases to pump the new inlet flow. This situation is shown in FIG.

The maximum rate of change of the computer-controlled heart rate is neglecting fine changes within one beat given by the following expression:

ÜS -Jr, (1,

Max

where R is the heart rate and ί is the maximum change in rate per beat. (S = 4.25 beats per minute / beat)

The general expression for the rate of change in heart rate is as follows:

German

where K is the fraction of heartbeats in which a filling pulse occurs. If a fill! Impulse occurs with every beat, if K = 1 and the maximum positive change in the heart rate occurs. If there are no filling pulses, K = O and the

609818 / 0A19

maximum negative change occurs. If filling pulses occur 50% of the time, K = 1/2 and di = heart rate remains constant.

Equation 2 is a differential equation with the known one Solution:

R = R _Q e, (3)

where R is the initial value of R.

The initial flow rate pumped through the heart is ideally:

Q ₂ = RV, (4)

where V is the ventricular volume .-- That accumulated in the atrium Blood volume is when the input flow rate Q1 is the output exceeds:

V = J (Q ₁ -Q ₂ ) (It

(5) O

assuming that the initial value of ν is zero.

If one considers a large-scale increase in Q ₁ at t = o, then for t> 0:

Q, = Q- O + X) 1 ο

Where Q = RV is the maximum possible initial exit flow rate without any accumulation in the atrium, and is the fraction at which the step elevation exceeds Q _0. When this step up occurs, fill pulses will occur on each beat, K = 1, up to a point after time t _m when the heart rate reaches the value necessary to make Q ₂ = Q ₁ . During this time, excess blood will accumulate in the atrium, so that the remaining atrial volume, the diastolic atrial volume V, will reach a maximum when Q ₂ = Q1 after time t and filling pulses continue to occur for each beat until the connection in the The atria is pumped out and the ventricle filling has reached the filling threshold level of 90%

609818/0419

falls behind. Therefore, R will continue to rise until the filling pulses begin to disappear, after which time R decreases until it reaches the required steady state value., The heart rate is at Q2 = Qj _} R = _j_ , so that the following applies:

(7)

^R o

The maximum value of V occurring at t = t is the volume, m.

which the atrium must be able to accommodate if a venous pressure build-up is to be avoided. The maximum value is the the following:

tm

Vm = f (Q ₁ -RV) dt

(8) O

For 0 <t <t Lt applies

^m R = R _o ^e (9)

K = 1 applies at t = t, R = R .. the following:

St ^R 1 = V ^m , (10)

t = 1 L · ^R 1 = 1 {n ^Q 1 = 1 {n (1 + x), (11) m - 7 - -

^R o ^{6 Q} o

Since Q ₀ =

From equations 8, 9 and 10 we get:

t _c

_r ^m St Q

Re dt = - ¹ In (Ux) -T- (R ₁ -R _n ) - (12)

609818/0419

Q ₁

Since R ₁ = rv- we get:

^Q r ^Q o7 ^Ö 1 Γ; ^χ

-VJ ⁼ / r ^{n (1 + x)} - ^

(13)

ν R '

(14)

OO

f (x) = in (1 + x) - - ~ = / _ ^ (" ^x ^ ⁿ * ¹⁵ >

n == 2

Examples:

f (0.1) = Ο.ΟΟ44Ο, f (0.15) = 0.00933, f (0.2) = 0.01565, f (0.3) = 0.0316, f (1) = 0.1931. "

Symbols:

t. - time variable

R - instantaneous heart rate

R _Q - initial value of R

R. - Heart rate for Q ₂ = Q ₁

S - maximum change in R per beat * (= 4.25 beats / minute /

Blow)

K - proportion of the time where filling pulses occur

Q ₁ - Blood flow rate into the iliac sodium

Q ₂ - blood flow rate from the heart ventricle

Q _n - value of the maximum ventricular output size when R = R _n

V - effective ventricular volume

ν - residual volume of that accumulated in the atrium over time Blood

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-ι

f (x) = {n (1 + x)

1 + x

As an example, the artificial heart operating in a steady state under computer control is a 10% Increase in venous return provided. This is completely absorbed by an instant increase in the ventricular filling, which is followed by a 10% rate increase. No atrial expansion is required.

As a second example, assume that the artificial heart is steady-state with nominally 100 beats per minute and is faced with a sudden 20% increase in venous return. This requires temporary blood storage in the atria and therefore an increase in the residual atrial volume. The final heart rate in this example is a 20% increase or 120 beats per minute. The rate at which the output flow equals the input flow is R ₁ = 110 beats per minute. During the transition, the maximum remaining atrial volume ratio is ν = R ^ f (χ)

ν 'S

and occurs with a response time of tm = 4r-tn (R ../ R). If one evaluates these quantities, one recognizes that

1 P ( 11O )
tm = ⁼ ° ^{0224 min =} 1/346 seconds.

The following also applies:

^R 1
χ = ■ 1 = 0.1

^R o

and f (x) = O.OO44O,

and therefore jan = 110 _{(Q QQ} . _A) _ _o -. g

so that the maximum remaining atrial volume required is 11.4% of the ventricular volume.

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Substitute loop data indicates that the artificial heart, under computer control, ejects approximately 80 ml per beat when 90% full. It can therefore be assumed that the ventricular capacity with a full fill is approximately 89 ml. Using V = 89 ml one obtains v _m = 0.114 (89) = 10.1 ml of residual atrial volume.

With the cycle time control in the present face cam systems is used, the atrial capacity change during each heartbeat is 0.36 V = 32 ecm. the end Attempts at A-V valve reversal during systole have found that the atria is also approximately 17 ml from this source had to absorb, which brings the atrial capacity change during the cardiac cycle to 32 + 17 = 49 ml.

The inclusion or accommodation of the 20% step increase at venous return would add an additional 10 ml, bringing the total atrial capacity required to 59 ml. Measurements of the actual atrial capacity indicate that only 60 ml actually without excessive atrial pressure increase are achievable, so that one can conclude that the present artificial heart with augmented atrial bladder and new, faster, computer-triggered 90% filling in the Is able to handle the 20% step increase in the venous return.

The above example assumes the new fast computer response and a 90% full probe trigger point. In all "In vivo" tests, the computer was previously slower (1.0 beats / per minute / beat) and the filling sensor was set to 95%. Assuming the same 20% step increase in the venous return, one would predict the following response :

The speed at t = tm is R ₁ = HS beats per minute, but the response time = tm = 8.39 seconds, since the filling sensor trigger is at 95%, whereby only 5% of the step increase can be accommodated by increased filling; this leaves 15% or χ = ο, 15 and f (x) = 0.00933, so that the following applies: ^ m = 1.073, ie

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the residual atrial volume = 1.073 (89) = 95.5 ml. The total atrial capacity should therefore be 96 - ^u 32 + 17 = 145 ml. Obviously this is not achievable, and if such a step change were to occur, increased atrial inlet pressures would result which would block venous return flow for most of the 8 second interval.

Before the above inventive control theory was developed, A number of other control methods have also been explored. These include the following procedures:

1) Continuous trend method; if the stroke volume is increased or decreased, the heart rate would increase or decrease on a percentage basis for incremental change in stroke volume on a stroke-by-stroke basis, where both the right and left ventricles would be analyzed for change;

2) fill rate method; if there were changes in the inflation rate and stroke volume percentage, the Heart rate increased or decreased;

3) full stroke volume procedure; if the one or other ventricles are filled, the heart automatically goes into systole, forcing all blood out of each Ventricle out, or the filled ventricle ejects and the other ventricle does not eject until it is completely is filled; However, the first ventricle to eject cannot eject a second time before the second ventricle has completed its discharge. A large number of synchronous and asynchronous conditions lie between these two limits, that can be set up.

None of the above procedures require any instrumentation or feelers in the bloodstream) and they are opposite movement and not sensitive to any spatial arrangement. These methods allow control of the rate and stroke volume with electrical, hydraulic or pneumatic logical

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Circuits. This allows the function of the nuclear Cardiac system without generating electrical energy for control.

The invention thus provides a heart rate control computer, which uses stroke volume as one of the main control parameters. This tax system always seeks to achieve a Rate to converge towards the stroke volume at the full value or at a predetermined high percentage of the full stroke volume. An essential element of the control logic is the automatic override (Override) the heart rate given by the right heart, creating sensitivity to central venous conditions will.

In the foregoing, the term atria was occasionally used instead of the term atria (atria). Also was in place used by reflux multiple reflux.

609818/0419

Claims (13)

Expectations ί 1) i Completely implantable replacement heart with a blood ^ ■ ^ pumping device for pumping blood to and from of the blood from the lungs, the arterial and venous systems, characterized in that a heart rate sensor is intended to determine the physiological requirements for the supply of the body with blood, and to generate a corresponding output, further wherein heart rate control means are connected to the blood pumping device are connected, and wherein the sensor -sur control of the number of heartbeats generated per minute serve by the pump due to the output of the heart rate sensor. 2) Device according to claim 1, characterized in that the blood pump has four chambers, two of which Pump chambers the ventricles of the natural heart and two reservoirs the atria of a natural heart and wherein each of the reservoirs has a valve leading to the pumping chambers, further each the pumping chambers has an outlet valve. 3) Device according to claim 1 or 2, characterized in that that the heart rate sensor has detector means, which are arranged in the wall of each of the pumping chambers, to determine the degree of filling of the chambers and to generate an output every time the chamber is in a has filled a predetermined amount. 4) Device according to claim 3, characterized in that the heart rate control device comprises a computer to continuously to check the beat rate of the pump and the output of the mentioned detector means, whereby the correct pumping rate after every predetermined number of strokes is determined again. 609818/0419 5) Method of controlling the pumping of an artificial Heart with a left and right ventricle and a left and right atrium characterized by the following Steps: Determination of the degree of filling of the left and right ventricles; Generating an output signal each time when the left or right ventricle receives a predetermined amount of blood; Control of the pumping rate Analysis of the mentioned output signals for the purpose of increase the pumping rate when the percentage of the mentioned output signals reaches a predetermined limit, and by then to lower the pumping rate when the percentage of the output signals mentioned falls to a predetermined limit. 6) Herζvorrichtung according to any one of claims 1 to 4 thereby characterized in that the right atrium is similar to the left Atrium 60 has a single inflow. 7) "Device according to one or more of the preceding Claims characterized in that the tricuspid valves are arranged in cylindrical housings which are attached to the Ends of branches 65,71 lie. 8) Device according to one or more of the preceding claims, characterized in that a sensor has an output signal generated every time a ventricle draws blood enough to make it 95% or more of its own To fill capacity, with a computer storing this information. 9) Device according to one or more of the preceding claims, characterized in that a fill detector is provided which supplies pulses to a filling counter. 10) Device according to one or more of the preceding claims, characterized in that drive pulses in Threshold amplifiers N7-N10 are generated. 609818/0419 - x- 11) Device according to one or more of the preceding Claims characterized in that triacs are used instead of some transistors. 12) Device according to one or more of the preceding claims, characterized in that the computer respond to a · drop in input blood flow is completely absorbed within a single beating interval through decreased ventricular filling. 13) Device according to one or more of the preceding claims, characterized in that the computer continuously the beat rate and beat volume are monitored for each beat and an analysis based on a Makes a series of immediately preceding heartbeats, for example based on five previous heartbeats Heartbeats. 609818/0419