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The artificial heart 1
THE ARTIFICIAL HEART
From Jarvic-7 to MLAH
PAPER BY
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INDEX
 ABSTRACT
 HISTORICAL ASPECTS OF ARTIFICIAL HEART
 CARDIOVASCULAR SYSTEM
 ELECTRICALLY POWERD TOTAL ARTIFICIAL HEARTS
 DRAW BACKS OF CONVENTIONAL ARTIFICIAL HEART
 STREAMLINED STRUCTURE OF MLAH ( Magnetically Levitated
Artificial Heart)
 CONTROL SYSTEM APPROACH IN DESIGN
 FUTURE WORK
 NEW WORDS
 BIBLIOGRAPHY
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ABSTRACT
As the worlds population grows the need for health care increases .In recent years progress in
medical care has been rapid especially in NEUROLOGY & CARDIOLOGY .In this paper we choose the
second and the best area that is cardiology to give details about artificial heart.
The quest for mechanical artificial heart is motivated by a tremendous human need .In united states
Alone 7, 00,000 deaths per year are attributed to heart disease .About 1 in 1000 babies is born with deformed
Heart and 1/3 of them are die infancy. Many of these people could be saved through heart transplantation.
But the supply of donor hearts is very limited. In addition transplant patient suffers the side effects of immuno
Suppressive drugs needed to prevent transplant rejection. Hence, mechanical circulatory assist is viewed as a
Very promising treatment for end stage heart disease.
In 1982, DeVries and associates, working in Koiffs lab at the University of Utch, belived that the
Pneumatic artificial heart had been developed to a level that could benefits to a patient with end stage heart
Disease when all other conventional methods of treatment had been exhausted. In a historic operation performed
on December 2, 1982, Barnery Clark, a 61 –year-old dentist with end edge cardiac disease,recived a pneumatic
artificial heart that was designed at university of Utch and was referred to as a Jarvik-7,named for Robert Jarvik ,
a co invigilator in kolff’s laboratory.
In this paper we put forward the basic cardiovascular system basic for design of artificial heart and the
artificial heart in olden days and latest advancement in heart design. The problems involved in old artificial heart
designs are…
 We have to supply power as well as signals for the artificial heart from out side of body. This is
Very difficult and inaccurate.
 Due to improper design of artificial heart the red blood cells may be damaged and clotting of
Valves occur.
 The life span is less and cost is more for this type of system.
Here we discussed how the draw backs are rectified by using “STREAMLINER MAGNETIC
LEVITATED HEART” which is existed in Jarvic-7 type of artificial heart. And design of the streamliner
and its structure.
At the end of this paper we can get the clear cut idea about these things.
 What is the basic structure of heart?
 What is the development steps involved in artificial heart using control system?
 How “STREAMLINED LEVITATED MAGNETIC HEART “differs from normal and
conventional artificial heart.
 Artificial system and its clinical application.
The detailed and elaborated description of these things is waiting for u r pleasant look inside the
paper.
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HISTORICAL ASPECTS
Having developed the first artificial kidney in the early 1940, Kolff, then professor of research
surgery at clevela, directed attention to the development of artificial heart. In 1958, 5 years after the
successful clinical use of heart lung machine for open heart operations, Akustsu and kolff 1958
reported that two compact vinyl pumps, powered by an external air compressor, had been need to
replace the function of the canine heart for a short period of time.
One decade after the initial studies in kolff’s lab the calf’s survival for 3 to 5 days was
reported. Attention was focused on pump designs, use of bio compatible materials for device
fabrication, and construction of more reliable power consoles.
In 1969pneumatic artificial hearts were used to support the circulation of patients hearts
had been removed for 39 to 64 hours respectively, while suitable donor hearts are identified. In both
cases heart transplantation was performed, but neither patient survived. Clearly, both the artificial
heart and transplantation were developed. I n those days artificial hearts are referred as bridges for
transplantation
In 1982, DeVries and associates, working in Koiffs lab at the University of Utch,belived that
the pneumatic artificial heart had been developed to a level that could benefits to a patients with end
stage heart disease when all other conventional methods of treatment had been exhausted. In a
historic operation performed on December 2 ,1982,Barnery Clark, a 61 –year-old dentist with end
edge cardiac disease,recived a pneumatic artificial heart that was designed at university of Utch and
was referred to as a Jarvik-7,named for Robert Jarvik ,a co invigilator in kolff’s laboratory.
CARDIOVASCULAR SYSTEM
During open heart surgery for installation of a valve prosthesis or correction of a congenital mal
formation, the heart cannot maintain the circulation. It is then necessary to provide extra-corporeal
circulation with a special machine called heart lung machine (Cardiovascular system).Further this is
also used to provide circulatory assistance to support a faulty heart. While doing open heart surgery,
it is necessary to bypass the heart to enable the surgeon to work in a blood less field under direct
vision. The heart lung mission replaces the functions of heart and lungs there by providing the rest of
the body with a continuous supply of oxygenated blood while the heart is stopped. Even though the
heart to be bypassed for the repair itself, for technical reasons both the heart and lungs are bypassed
by present day method.
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CARDIOVASCULAR-SYSTEM
MECHANICAL FUNCTIONS OF THE HEART
 In an intact heart venous or unoxygenated blood is return to the right side of heart at a pressure of 05mm Hg and oxygen saturation is below 75%.
 From the right side of the heart the blood is pumped into the lungs through pulmonary arteries.
 In the lungs the blood is oxygenated to about 95%-98% saturation and then it is going to the left
atrium which act as receiving chamber.
 From there the blood flows into the left ventricle through the martial valve the left ventricle is called
the more powerful chamber of the heart.
 The ventricle ejects the blood into aorta with peak pressure ranging from 100-150 mmHg.
 Since the contraction of the left ventricle is rhythmic the resultant flow in the aorta is pulsatile,
reaching a systolic peak pressure of about 90-150 mmHg with 80mmHg as a mean. Systole is the
period of contraction of the ventricular muscles during that time blood is pumped into the pulmonary
artery aorta Diastole is the period of dilation of the heart chambers as they fill with blood.
The heart pumps about 5 liters of blood per minute at any time the veins contain 75%-80% of the blood
volume and arteries contain 20%-25% of blood
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ELECTRICALLY POWERED ARTIFICIAL HEART FOR HEART TREATMENT
Experience with the pneumatically powered heart, both in laboratory and in the clinical
setting, has confirmed the disadvantage of prestigious passage of power lines. A major break through
in this transmission of energy in the form of pressurized fluid across the skin does not appear to be
imminent. A principle widely used in transformers and other electronic devices is applicable for this
heart also. A power requirement of more than a million times that of a pace maker from
consideration an artificial heart solely depend on an implantable battery. It consists of two
implantable blood pumps activated by a miniature electric motor. Energy for this system is supplied
continuously to a primary coil on the surface of skin by either house current or a wearable external
battery. The secondary coil, positioned under the skin and energized by the primary coil, actuates the
electric motor. An element of safety and comfort is provided by a sophisticated implantable
rechargeable battery. This implanted battery supplies power to the heart for about 30 minutes.
In this design, a high speed, reversing, brushless, DC motor is coupled to an axial flow
pump, located between the two ventricles. This motor pump unit is positioned with in a short conduit
that joins what were the pneumatic ports of the two ventricles. TheGoal of UTCH program is to
develop an implantable nickel cadmium rechargeable battery, electromagnetic induction energy
transfer, and a bidirectional infrared data link.
The out put of the electric artificial heart can be varied by changing the stroke or pumping
rate. As with the pneumatic heart, the change in out put can occur secondarily to change in filling
pressure or in response to man electronic heart, the change in filling pressure or in response to an
electronic control based on arterial or arterial pressures, or their analogs .electrically powers artificial
heart s have lagged behind their pneumatic counter parts, in part because of their complexity of
control. In any design of an artificial heart ,provisions must be made to prevent arties in the event
that there is inadequate blood to fill the ventricle .In the pneumatic design, present low diastolic
vaccum,prevent arterial collapse; the hydraulic or mechanical types of electric heart must rely on
other techniques. In the hydraulic design, pressure sensor is used in the hydraulic fluid behind each
ventricle, which through appropriate electronic circuitry, promptly slows or stops and reverses axial
pump movement when a significant negative pressure is registered.
The transcutaneous energy transmission system (TESTS) consists of primary coil of Litz
wire energized at 150kHz.The secondary coil is implantable under the skin and provides energy to
Power the motor and associated electronics and to recharge the implanted batteries. The energy
required for the electric heart can be transmitted, with the coils 5-10mm apart, with 70% efficiency
and no noticeable rise in skin temperature or nutritional effect on the interposioned skin. Important
information can be transmitted to one from the implanted electronics by modulation of the 150-kHz
power signal, which allows one to assess device function and battery condition and adjust operation
modes.
The power in put required for the electric heart is between 10&20W, and is provided easily
by conventional house current. For portable function the heart must be powered by an external
rechargeable battery. In addition to the batteries, such a pack must include the electronics required
for recharging them and a system to indicate the power remaining and the status of the battery. At
present Ni-Cd batteries represent the best type of batteries available (~ one pound of battery is
required to operate heart for an hour).
Development of higher- energy density batteries is a current focus of industrial research
advances in this area produce a lighter power pack for patients to carry . The most advanced
technique for transmitting the power is by wireless transmission.
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DRAW-BACKS OF CONVENTIONAL ARTIFICIAL HEART
Artificial hearts have long dating back to the early animal studies of kolff and akutsu in 1957.
The phrase “ARTIFICIAL HEART “is applied to number of treatment technologies in corpora ting
mechanical assist devices. One technology is the total artificial heart which involves removal replacement of
patients own heart with mechanical pump. The second and the leading approach uses “helper hearts” called
ventricular assist devices, with the left ventricular assist devices LVDS being most common.
LVAD contributions previous to this lead is Novascor LVAD solenoid activated LVAD .But the main
draw backs of this type of system are

These are having pump pusatility.But recent researchers are shown that there is no need for
pulsatility.

Nimbus heart mate-2 and jarvic 2000 are examples of rotatary pumps having no
pulsatilitybut still have following drawbacks
 There is a Rick of clotting and the release of clot material into the blood stream in the
form of emboli, which cause stroke or other organ damage.
 The tendency of these pumps tom form clots is reduced with anti coagulant drugs, but
these drugs often cause hemorrhaging.
 Current rotatary pumps use blood as a lubricant with in hydro dynamic bearings.

Consequently the red blood cells in the pumps may be damaged, and in turn send
bio chemical signals that instigate clotting.
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The Rick of death when LVADs are used relative to more conventional medical treatments. The
technical issues of clotting, blood damage, mechanical reliability, and the promises of LVAD for
treating heart disease is the back group against which we develop magnetically levitated LVAD.In
this there is a magnetically levitated pump impeller to radically improve reliability and the quality
of the blood through this axial flow pump.
DESIGN OF THE STREAMLINER
The over all streamliner circulatory assist system depicted in fig. the pump draws
blood from the apex of left ventricle and pumps blood, in parallel with the left ventricle, into the
aorta. the pump has been the primary focus of our work, since it contacts the blood and the primary
power consumer in the circutory.other sub systems include an implanted battery to enable patients to
take showers with out external pack, a transcutones electrical system (TESTS) transmitting power
and signals inductively through the skin, an internal controller for levitation and pump speed control,
and battery for power and system monitoring. Other blood contacting components are the inflow and
out flow cannulewhich serves as artificial blood vessels. At the time of animal trails the stream liner
system consisted of an internally implanted magnetically levitated pump, cannule, and an
extetnalcontroller and power source. This was the first fully magnetically levitated system to be
tested in animals.
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A cross section of the stream liner pump, shown in fig. It depicts the compact design
that combines brushless dc motor, fixed-flow impeller, and magnetic levitation componets.The small
interior volume of streamliner reduce the Rick of clot formation in several ways. The path in which
blood flows has been designed and optimized by computational fluid dynamics, to be highly
“streamlined”.
The flow is slow enough to prevent the damage of blood cells, yet fast enough to prevent blood
clots. By using magnetic levitation, we are able to design levitation gaps that are wide enough to
prevent blood damage and simultaneously eliminate stigmatizations zones; these are unique features
of our design approach.
In addition, magnetic levitation eliminates mechanical bearing wear. Indeed, the streamliner
technology is expected to revolutionize mechanical cardiac assist technology. Although deceptively
small, the streamliner is an immense control engineering challenge. The design objective is to
magnetically levitate and rotate pump impeller in the blood stream while minimizing pump size,
blood damage, and battery size and system weight. The selection of control system concept is the
most difficult decision, and all aspects of design, including the actuator and sensor design, must be
optimized.
Further, since cables and connectors are week links in terms of reliability, the number of
control channels must be minimized. In response to these requirements we develop the pump
topology shown in fig3.The key design elements are cylindrical magnetically levitated rotating
impeller, which is supported on perment magnet radial bearing. The inner rays of these bearings are
fixed and supported by out flow hub and inlet stator blades.
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The axial position of impeller is actuated by the voice coils interacting with the outer
rays magnets of bearing. Sensing of axial position is accomplished with eddy-current sensor probes.
The out puts of these sensors are summed to render pitching motions of impeller unobservable and
decoupled from the axial feed back loop. Obviously, the small package requirements for anatomic fit
have forced us to use a very integrated design. Although the rotor is magnetically controlled 6
degrees of freedom, only 2 degrees are actively controlled. By Earn Shaw’s therom, the sum of the
linear stiff nesses sum to zero, so there is at least one axis along which the motion is un stable By
symmetry about the axial axis, we see that rotational element is zero.
The stream liner system has been an exciting challenge from control point of view. We can
say that sensors actuators design define the over all system performance.” Zero-placement” has
turned out to be an invaluable technique in the active magnet levitation design,mathametical
modeling and optimization are essential, are rendering certain states unobservable to the active
controller is required. In addition to actively controlled feed back loops, perment magnet s has been
used. The set of control laws achievable with passive feed back is much less than the field of
rotational transfer functions, how ever! In simple terms, the stream liner is an actuator for human
cardiovascular system .In the future, external feed back systems responding to physiologic needs of
patient may further improved biocompatibility.
CONTROL SYSTEM APPROACH
Axial positioning of the impeller is likely the most interesting control problem, and
block diagram shown below .Working around the loop, the top center block is the rotor axial
dynamics determined by rotor mass and unstable or negative axial stiffness of the radial bearings.
The axial motion of the impeller is measured with two eddy-current sensors, which we designed to
have very low noise crystal oscillator current source and impedance changes are detected with
coherent demodulator.
The input referred current noise is surprisingly small and roughly 1nm/root Hz over the
control band width .The sensor out put drives a modified PID controller design by zero placements.
The controller has zero at zero so that there is no dc gain; if steady state is reached, the voice coil
theoretically dissipates no power. The objective of this controlled is to levitate and not to precisely
center the rotor axially; hence, there is freedom to let the rotor move axially to save the power.
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When a disturbance force is applied to the rotor, the rotor moves towards the
disturbance. The more UN stable the bearings are in axial direction, the less motion is required to
balance the disturbance force. In stability can be exploited with control! When standing in a wind
strom, we use our body in the same way. From all these things we can say control system is to
stabilize the system.
The zero in the controller minimizes power consumption and voice coil heating and is
commonly referred to as virtual zero power (VZP) control. Small voice coil are quite in sufficient
and initial levitation only pore for this system is on the order of 100W.Thankfully, levitation, takes
only few milliseconds. After levitation, the coil pore typically drops to 0.5 w during pumping .A
standard figure of merit for voice coil actuator is the force per root watt, which is to be high .We
design these actuator to meet these needs by choosing a geometry that was compatible with pump
geometry and then parametrizing the design for optimization in a magnetic finite element analysis
code. The optimization process dictated the localization and shape of the iron poles in the outer race
of the artificial bearing .Usual constraints were placed on the voice coil design with regard to radial
magnetic force. Since any iron in the voice coil support produce negative stiffness, iron was
eliminated from voice –coil actuator stator design .Similarly, a slot ness motor stator was used in the
motor to move away the motor stator iron as far as possible.
The motor was modeled directly from max wells equations in 2-D.Closed from
expressions relating the motor geometry and coil current density to power and efficiency were
derived and used in the system optimization. This is quite unlike the more common shopping activity
used in the motion control problems. The resulting design has a computed efficiency at 85% at
7,500rpm, even with the limits on stator iron .Since wires and connectors tend to reduce reliability
numbers, we use sensor less motor control. A sterling achievement in motor control technology is
embodied in single – chip sensor less motor controllers developed for disk-drive industry.
The design of the passive radial bearings was accomplished with new closed form
models for magnetic stiffness .In this case , we are stabilizing the rotor radial position with one hand
tied behind our backs in the since that we have control over stiffness and not damping . Moreover,
passive magnetic bearings have essentially no damping so that the blood around the rotor supplies all
damping.
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Significant radial forces are produced by the rotor due to residual imbalance. The streamlined
rotor in our model has two types of frequencies 4000 and 8000 rpm, respectively.The pump was
designed to operate in between these two speeds to avoid touchdown of the impeller blades. This
design was accomplished with a simple rigid body model of the impeller and our closed-form
expressions for bearing stiffness.
FUTURE WORK:
In future ,artificial heart will be ”shelf ” items ,with an availability similar to that of pace makers and
prosthetic valves. Many exciting control issues are remaining unsolved in magnetically levitated artificial
heart, and there is much more to contribute in way of control design methodology. Work is needed in
controlling the pump speed in response to physiologic need and in the design of physiologic sensors, and
further power savings is possible.
NEW WORDS:
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Pulmonary circulation
Systematic circulation
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=
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Transplant
Emboli
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=
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Levitate
Indeed
Immense
Impeller
=
=
=
=
the circuit path for blood flow through lungs.
the circulatory system that supplies oxygen
And nutrients to the cells of the body.
remove and replace (or) establish.
clotting the blood by air bubble.
rise (or) cause to rise and float in air.
truly
extremely great
drive forward
BIBLIOGRAPHY
[I] IEEE magazine on control systems;
[2] “Bio- Medical instrumentation” by Mr.Armrugam
[3] “The invention of artificial heart” by w.j.Kolff
[4] “Bio-Medical instrumentation in clinical laboratory” by Cronic
[5] “Long-tearm use of a left ventricular assist devices for end edge heart failure” by E.A.Rose