2. Introduction: Fig 2.1 The Abiocor system The AbioCor Total Artificial Heart System is designed to give patients with heart failure an option other than heart transplant and Ventricular Assist Device (VAD). VAD Systems are intended for patients with a failing left ventricle; the VAD is implanted and replaces the ventricle by acting as a pump. Heart Patients hoping to extend their life expectancy by having a heart transplant may not be able to realize their hope because the amount of donor hearts in relation to the amount of patients in need of a donor heart is 1 Department of ECE
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similar physical appearance to the appearance of a natural heart. This is because it contains
inflows and outflows; aside from the similarity in inflows and outflows, the thoracic unit is
very different from a natural heart because it is made of plastic and titanium and it is not full
of veins as a natural heart is. The external and internal TETs are almost identical in their
design, they both have a round top and a long thin end (similar to the shape of a lollipop);
however, the external TET is covered with silicone. The rest of the AbioCor System’s
components have geometric designs (mostly rectangular) and are not extravagant in their
appearance. For example, the implanted controller and the implanted battery appear very
similar; they are both cased in titanium, they both are covered in the solid color of titanium,
and they both have the same shape. The console and the PCE control module are generally
boxes with no artistic designs or variety in color.
4. Orgins
A synthetic replacement for the heart remains one of the long-sought holy grails of modern
medicine. The obvious benefit of a functional artificial heart would be to lower the need
for heart transplants, because the demand for organs always greatly exceeds supply.
Although the heart is conceptually simple (basically a muscle that functions as a pump), it
embodies subtleties that defy straightforward emulation with synthetic materials and power
supplies. Consequences of these issues include severe foreign-body rejection and externalbatteries that limit patient mobility. These complications limited the lifespan of early human
recipients to hours or days.
5. Early developments
A heart-lung machine was used in 1953 during a successful open heart surgery. Dr. John
Heysham Gibbon, the inventor of the machine, performed the operation and developed the
heart-lung substitute himself.
On July 3, 1952, 41-year-old Henry Opitek , suffering from shortness of breath, made medical
history at Harper University Hospital at Wayne State University in Michigan. The Dodrill-
GMR heart machine, considered to be the first operational mechanical heart, was successfully
used while performing heart surgery
Dr. Forest Dewey Dodrill used the machine in 1952 to bypass Henry Opitek's left ventricle
for 50 minutes while he opened the patient's left atrium and worked to repair the mitral valve.
In Dr. Dodrill's post-operative report, he notes, "To our knowledge, this is the first instance of
survival of a patient when a mechanical heart mechanism was used to take over the complete
body function of maintaining the blood supply of the body while the heart was open and
operated on."
The scientific interest for the development of a solution for heart disease developed indifferent research groups worldwide.
Early designs of total artificial hearts
In 1949, a precursor to the modern artificial heart pump was built by Dres. William
Sewell and William Glenn of the Yale School of Medicine using an Erector Set, assorted
odds and ends, and dime-store toys. The external pump successfully bypassed the heart of a
dog for more than an hour.
On December 12, 1957, Dr. Willem Kolff, the world's most prolific inventor of artificialorgans, implanted an artificial heart into a dog at Cleveland Clinic. The dog lived for 90
minutes.
In 1958, Domingo Liotta initiated the studies of TAH replacement at Lyon, France, and in
1959-60 at the National University of Cordoba, Argentina. He presented his work at the
meeting of the American Society for Artificial Internal Organs held in Atlantic City in March
1961. At that meeting, Dr. Liotta described the implantation of three types of orthotropic
(inside the pericardial sac) TAHs in dogs, each of which used a different source of external
energy: an implantable electric motor, an implantable rotating pump with an external electric
motor, and a pneumatic pump.
In 1964, the National Institutes of Health started the Artificial Heart Program, with the goal
of putting a man-made organ into a human by the end of the decade.
In 1967, Dr. Kolff left Cleveland Clinic to start the Division of Artificial Organs at
the University of Utah and pursue his work on the artificial heart.
- In 1973, a calf named Tony survived for 30 days on an early Kolff
- In 1975, a bull named Burk survived 90 days on the artificial
- In 1976, a calf named Abebe lived for 184 days on the Jarvik 5 artificial heart.
- In 1981, a calf named Alfred Lord Tennyson lived for 268 days on the Jarvik 5.
Over the years, more than 200 physicians, engineers, students and faculty developed, tested
and improved Dr. Kolff's artificial heart. To help manage his many endeavors, Dr. Kolff
assigned project managers. Each project was named after its manager. Graduate student
Robert Jarvik was the project manager for the artificial heart, which was subsequently
In 1981, Dr. William DeVries submitted a request to the FDA to implant the Jarvik 7 into a
human being. On December 2, 1982, Dr. Kolff implanted the Jarvik 7 artificial heart into Dr.
Barney Clark. Clark was hours from death prior to the surgery. He lived for 112 days with the
artificial heart.
fOn February 11, 2009, Dr. Kolff died at the age of 97 in Philadelphia.
First clinical implantation of a total artificial heart
On the morning of April 4, 1969, Domingo Liotta and Denton A. Cooley replaced a dying
man's heart with a mechanical heart inside the chest at the Texas Heart Institute in Houston as
a bridge for a transplant. The patient woke up and recovered well. After 64 hours, the
pneumatic-powered artificial heart was removed and replaced by a donor heart. Replacing the
artificial heart proved to be a bad decision, however; thirty-two hours after transplantation,
the patient died of what was later proved to be an acute pulmonary infection, extended to
both lungs, caused by fungi, most likely caused by an immunosuppressive-drug complication.
If they had left the artificial heart in place, the patient may have lived longer
The original prototype of Liotta-Cooley artificial heart used in this historic operation is
prominently displayed in The Smithsonian Museum "Treasures of American History" exhibit
in Washington, D.C.
First clinical applications of a permanent pneumatic total artificial heart
The eighty-fifth clinical use of an artificial heart designed for permanent implantation rather
than a bridge to transplant occurred in 1982 at the University of Utah. Artificial kidney
pioneer Dr. Willem Johan Kolff started the Utah artificial organs program in 1967. There,
physician-engineer Dr. Clifford Kwan-Gett invented two components of an integrated
pneumatic artificial heart system: a ventricle with hemispherical diaphragms that did not
crush red blood cells (a problem with previous artificial hearts) and an external heart driver
that inherently regulated blood flow without needing complex control
systems. Independently, ventriloquist Paul Winchell designed and patented a similarly shaped
ventricle and donated the patent to the Utah program. Throughout the 1970s and early 1980s,veterinarian Dr. Donald Olsen led a series of calf experiments that refined the artificial heart
and its surgical care. During that time, as a student at the University of Utah, Dr. Robert
Jarvik combined several modifications: an ovoid shape to fit inside the human chest, a more
blood-compatible polyurethane developed by biomedical engineer Dr. Donald Lyman, and a
fabrication method by Kwan-Gett that made the inside of the ventricles smooth and seamless
to reduce dangerous stroke-causing blood clots. On December 2, 1982, Dr.William
DeVries implanted the artificial heart into retired dentist Dr. Barney Bailey Clark (born
January 21, 1921), who survived 112 days with the device, dying on March 23, 1983. BillSchroeder became the second recipient and lived for a record 620 days.
Contrary to popular belief and erroneous articles in several periodicals, the Jarvik heart was
not banned for permanent use. Today, the modern version of the Jarvik 7 is known as the
SynCardia temporary Cardio West Total Artificial Heart. It has been implanted in more than
800 people as a bridge to transplantation.
In the mid-1980s, artificial hearts were powered by dishwasher-sized pneumatic power
sources whose lineage went back to Alpha-Laval milking machines. Moreover, two sizable
catheters had to cross the body wall to carry the pneumatic pulses to the implanted heart,
greatly increasing the risk of infection. To speed development of a new generation of
technologies, the National Heart, Lung, and Blood Institute opened a competition for
implantable electrically powered artificial hearts. Three groups received funding: Cleveland
Clinic in Cleveland, Ohio; the College of Medicine of Pennsylvania State University (Penn
State Hershey Medical Center ) in Hershey, Pennsylvania; and Abiomed, Inc. of Danvers,Massachusetts. Despite considerable progress, the Cleveland program was discontinued after
the first five years.
Polymeric trileaflet valves ensure unidirectional blood flow with a low pressure gradient and
good longevity. State-of-the-art transcutaneous energy transfer eliminates the need for
electric wires crossing the chest wall.
The first AbioCor to be surgically implanted in a patient was on July 3, 2001. The AbioCor is
made of titanium and plastic with a weight of two pounds, and its internal battery can berecharged with a transduction device that sends power through the skin. The internal battery
lasts for a half hour, and a wearable external battery pack lasts for four hours. The FDA
announced on September 5, 2006, that the AbioCor could be implanted for humanitarian uses
after the device had been tested on 15 patients. It is intended for critically ill patients who can
not receive a heart transplant. Some limitations of the current AbioCor are that its size makes
it suitable for only about 50% of the male population, and its useful life is only 1–2 years. By
combining its valved ventricles with the control technology and roller screw developed at
Penn State, Abiomed has designed a smaller, more stable heart, the AbioCor II. This pump,
which should be implantable in most men and 50% of women with a life span of up to five
years, ad animal trials in 2005, and the company hopes to get FDA approval for human use in
2008.
First clinical application of an intrathoracic pump
On the evening of July 19, 1963, E. Stanley Crawford and Domingo Liotta implanted the first
clinical Left Ventricular Assist Device (LVAD) at the Methodist Hospital in Houston, Texas,
in a patient who had a cardiac arrest after surgery. The patient survived for four days under
mechanical support but did not recover from the complications of the cardiac arrest; finally,the pump was discontinued, and the patient died.
Another VAD, the Kantrowitz CardioVad, designed by Adrian Kantrowitz, MD, boosts the
native heart by taking up over 50% of its function. Additionally, the VAD can help patients
on the wait list for a heart transplant. In a young person, this device could delay the need for a
transplant by 10–15 years, or even allow the heart to recover, in which case the VAD can be
removed.
The first heart assist device was approved by the FDA in 1994, and two more received
approval in 1998. While the original assist devices emulated the pulsating heart, newer
versions, such as the Heart mate II, developed by the Texas Heart Institute of Houston,
Texas, provide continuous flow. These pumps (which may be centrifugal or axial flow) are
smaller and potentially more durable and last longer than the current generation of total heart
replacement pumps. Another major advantage of a VAD is that the patient can keep the
natural heart, which can receive signals from the brain to increase and decrease the heart rateas needed. With the completely mechanical systems, the heart rate is fixed.
Several continuous-flow ventricular assist devices have been approved for use in the
European Union, and, as of August 2007, were undergoing clinical trials for FDA approval.
6. Internal Components:
6.1. Thoracic Unit (Artificial Heart):
The thoracic unit weighs slightly more than two pounds (0.9 kg) and is
about the same size and shape of a natural heart. It is made of titanium, and Angioflex, a
polyurethane plastic. The thoracic unit is implanted in the chest, where a natural heart would
be located, and connects to the right and left atria, the aorta, and the pulmonary artery. In
order for blood to enter and exit from the unit, grafts must be sewed onto the right and left
atria, the aorta, and pulmonary artery of the patient. They must also be sewed onto the
thoracic unit’s four heart valves. These grafts then allow for the two arteries and the two atria
to each be snapped onto the graft of one of the heart valves. Conclusively, one valve will be
snapped onto the aorta, another valve will be snapped onto the pulmonary artery, another to
the left atrium and another to the right atrium.
The thoracic unit contains two hydraulic motors; one keeps the blood
pumping from each ventricle (blood pump), and the other operates the motion of the four
heart valves. The pumping from these hydraulic motors is caused by an oscillating pusher
plate that squeezes sacs that then emit blood to the lungs and to the rest of the body (Total
Artificial Hearts (TAH)). Additionally, the unit has a left and a right blood pump. Each blood
To maintain operation, the AbioCor System must first have a source of
power; depending on whether or not the patient is mobile, this power source will either be the
console or the PCE control module. Both power sources cause the AbioCor System toperform the same function and to do so in a similar way. The only difference between the two
sources is that the console receives its energy from a power outlet and is stationed in one
place and the PCE control module receives its energy from a battery pack carried in the PCE
battery bag and is portable. From the power source, energy will travel through the external
TET in the form of radio waves. These radio waves will penetrate the patient’s skin and enter
the implanted TET, which will then convert the radio waves into electrical energy. This
electrical energy will travel to the implanted battery where it will remain to keep the battery
charged. The energy stored in the battery will be used by the implanted controller to monitor
the thoracic unit’s (artificial heart) cardiac output rate. This energy supplied to the artificial
heart keeps the blood flowing into the heart and out into the body. The heart will take turns in
sending blood to the lungs and to the rest of the body because it cannot send blood to both
areas simultaneously as a natural heart would.
Besides controlling the artificial heart’s cardiac output rate, the
implanted controller also oversees the performance of all internal components to make sure
that everything is working properly. The information gathered by the controller’s supervising
is sent to the AbioCor System’s power source (the console or the PCE control module) using
wireless technology. If the power source detects a problem, an alarm light or an alarm sound
notifies the patient. Otherwise, if no problems are detected the AbioCor System follows a
cyclic function and continues to operate.
Ventricular assist devices represent a method of providing temporary mechanical circulatory
support for those patients not expected to survive until a heart becomes available for their
transplant. The scarcity of donor organs has led to the development of interim interventions,
such as mechanical assist devices.
A variety of devices have received approval from the U.S. Food and Drug Administration
(FDA), encompassing both biventricular and left ventricular devices, as well as devices that
are intended to be used in the hospital setting alone and those that can be used as an
outpatient. Devices that can be used in an outpatient setting while the patient awaits a human
donor heart include the HeartMate II and HeartMate Vented Electric Left Ventricular AssistSystem® (Thoratec Corp) and the Novacor LVAS® (World Heart, Inc.). In these two
systems, the device is surgically placed entirely within the thoracic and abdominal cavity and
connected to the power source by a percutaneous drive line.
Left ventricular assist devices (LVAD) are most commonly used as a bridge
transplantation. More recently, given the success of LVADs for prolonged periods of time,
there has been interest in using LVADs as permanent "destination" therapy for patients with
end-stage heart disease who are not candidates for human heart transplantation due to age or
other comorbidities. In November of 2002, the HeartMate device received FDA approval as
destination therapy. World Heart Corp., makers of NovaCor® LVAS, announced in 2003 that
it is engaged in clinical trials of NovaCor® VAS as destination therapy.
To date, only pulsatile LVAS devices are FDA approved for long-term use. Non-pulsatile
axial flow devices are smaller in size and have other technical advantages over pulsatile
models. The Jarvik 2000, a non-pulsatile axial flow blood pump, is in phase I clinical trials.
In April 2000, the FDA granted the Texas Heart Institute at St. Luke's Episcopal Hospital in
Houston, Texas an investigational device exemption to conduct clinical trials of the Jarvik
2000 in 25 patients as part of phase I clinical trials. The study was expanded to include the
Cleveland Clinic. Between March 2000 and February 2002, 20 patients received the device.
Devices have also been designed specifically for short-term use, typically in the post-cardiotomy setting for patients who are unable to be weaned off cardiopulmonary bypass or
for "high-risk angioplasty." The Thoratec VAD System® is paracorporeal in that the pump is
external and is connected by cannulas to the heart and great vessels. The TandemHeart
(CardiacAssist) is another device specifically designed for short-term stabilization of patients
in the postoperative setting. This device, which had its three components cleared for
marketing through the FDA 510(k) process, is unique in that it allows for percutaneous
access through the femoral vein, permitting rapid deployment. In addition, it is the first
ventricular assist device that uses continuous axial flow, as opposed to pulsatile flow.
In February 2004, the FDA approved the DeBakey VAD® Child under the Humanitarian
Device Exemption (HDE) approval process. According to the FDA, this device is indicated
under HDE for both home and hospital use for children who are between ages 5 and 16 years
and who have end-stage ventricular failure requiring temporary mechanical blood circulation