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artificialheart.doc (Size: 179.5 KB / Downloads: 288) ARTIFICIAL HEART
S.Vijay Bhaskar V.Anand
Email: email@example.com Email:firstname.lastname@example.org
Phone. No: 9394195844 Phone. No: 9948151573
ELECTRONICS & INSTRUMENTATION
SIR C. R. REDDY COLLEGE OF ENGINEERING,
Vatluru, Eluruâ€ 534006.
Â¢ Heart Anatomy and Disease
Â¢ Effectiveness of Transplantation
Â¢ Total Artificial Heart Development
Â¢ A Complete Artificial Implantable Heart
Â¢ Design of the Complete Artificial Implantable Heart
Heart disease currently affects more than 100 million people around the World
Some of these diagnosed cases are so severe that patients may not survive the
wait for a donor heart. Biomedical scientists and engineers have developed
devices such as defibrillators, pacemakers, and artificial hearts to keep patients
alive until a donor heart becomes available. Artificial hearts prove to become
the most effective choice for severely ill patients. In 1995, 2400 heart transplants
were performed while 4000 patients awaited donor hearts; 731 of these patients
died waiting. With the number of patients suffering from severe heart disease
increasing and the number of donor hearts remaining constant, an immediate need
exists for the advancement of artificial hearts. Artificial hearts provide a viable
option for patient awaiting heart transplantation. Future developments on artificial
hearts have the hope of eliminating the need for the transplantation completely .
Artificial hearts have been around since the early 1980s. TheJarvik-7
became the first permanent artificial heart in 1982. The patient implanted
with the device lived for 112 days on the artificial organ. Patient was unable
to leave his bed and was in severe pain until his death. Human life could be prolonged
by artificial means, but patients still had to suffer after implantation. At this time,
the risks, such as sub-standard quality of life, outweighed future benefits of
artificial heart technology and all research was put off until positive results could
be expected. After many technological Developments in materials science as well as
pharmaceuticals, artificial heart technology is once more in the spotlight. The
Complete Artificial Implantable Heart and the Ventricular assist device provide a
mobile option for severely ill cardiac patients.
2. Heart Anatomy and Disease
To completely understand the design development of the
device, it is imperative to know the functions and diseases of the human heart.
The heart is the most important organ in the human body. Even if a patient is
considered brain dead, the patient is still considered alive until the heart stops
beating. Though it serves such an essential role the mechanisms behind the human
heart are relatively simple. The heart is pump that works based on positive
displacement. Positive displacement refers to a change in volume within a
chamber due to the movement of fluid across its boundaries. From this volume
change, pressure differences arise that drive the blood pumping process. The
heart has four chambers. These chambers or cavities are the right atrium right
ventricle, left atrium, and left ventricle. Each chamber connects to a one-way
valve. When a cavity contracts, a valve opens and blood flows into the chamber.
In summary, there are four valves, each associated with individual chamber. The
following list identifies each valve with respective chamber.
Â¢ Mitral valve & left atrium
Â¢ Aortic valve & left ventricle
Â¢ Tricuspid valve & right atrium
Â¢ Pulmonary valve& right ventricle
The heart pumps blood to the body in two steps. First, the right and
left atria contract, moving blood to the right and left ventricles. Second, the
ventricles contract simultaneously to push the blood out of the heart and through
the body. The heart then relaxes, allowing new blood to fill the atria. This
contraction of the atria and the ventricles makes up a heartbeat. Figure1
illustrates the anatomy of the human heart.
The human body needs oxygen in order to live. The circulatory
system is responsible for filtering oxygenated blood and deoxygenated blood from the
body. Blood enters in to heart through two veins, the superior vena cava and the
inferior vena cava. Both of these veins feed de-oxygenated blood into the right
atrium. The right atrium contracts sending blood to the right ventricle. Blood flows
from the right ventricle through the lungs by means of the Pulmonary valve
.With in the lungs the deoxygenated blood becomes oxygenated. The newly
oxygenated blood flows through left atrium and ventricle, and the blood disperses
through the body. Figure 2 recaps flow of blood through the heart.
Like all machines, the Heart can malfunction numerous ways. Cardiovascular
disease occurs when the heart becomes clogged, broken down, or in need of
repair. Severe cardiovascular disease is the leading cause for heart
transplantation, but other malfunctions such as valve damage and chamber problems
also require the need for a new heart. Currently, 12 million Indians have at least
one kind of cardiovascular disease. Heart disease is the number one cause of death in
India. Since many conditions fall under the in category of cardiovascular disease,
we will focus on the two main causes for heart transplantation and artificial hearts:
coronary heart disease and congestive heart failure .
Coronary heart disease (CHD) afflicts approximately 20 percent of all
patients diagnosed with cardiovascular disease. Patientâ„¢s symptoms can range
from being mild to intolerable. CHD is the hardening of artery walls inside the
heart. Arteries are essentially piping that connects heart valves together. In CHD ,
the transportation of blood becomes impaired when a mixture of fat and
cholesterol, or plaque, lines the arteries the buildup of plaque restricts the free flow of
blood, which induces pressure drop between the valves. The heart compensates for
this pressure drop by pumping harder in order to provide enough blood for the
entire body Patients suffering from CHD often exhibit symptoms such as severe
chest pain and fatigue due to the lack of oxygenated blood. For severe cases of
CHD, the only cure is a heart transplant .Congestive heart failure (CHF) arises when
the heart does not efficiently pump blood. Since the heart is unable to pump enough
oxygen-rich blood, blood starts to fill in the lungs, which leads to congestion.
Therefore, the heart must work harder in order to meet the bodyâ„¢s oxygen demands.
This behavior causeâ„¢s excessive wear to the diseased organ initial symptoms of CHF,
such as fatigue and swelling of the ankles, is usually so option. Until the condition
becomes much more severe. As the disease progresses patients start to suffer from
shortness of breath and palpitations even while remaining stationary. For
extremely, severe cases, transplantation is the only option.
3. Effectiveness of Transplantation
Surgeons started developing heart transplantion techniques early as
the 1900s. Preliminary transplantations conducted on animals proved to have fatal
cosequences caused by the donor organ rejection.Therefore doctors were skeptical to
try transplantation procedures on humans.
In 1905, the first cardiac heart transplant was performed by two
surgeons on a dog. They removed the heart of a dog and placed into the chest
cavity of larger dog (Transplantation) Then the heartbeat resumed but the dog
transplantation. Though the experiment had fatal results, this event stunned the
medical community and spearheaded further research in field of cardiac expired
two hours after the operation.
By definition, heart transplantation is The replacement of a
patientâ„¢s diseased or injured heart with a healthy donor heart. Reaching the exact
definition of transplantation proved to be an extremely difficult task. In order to deter
organ rejection after transplantation, research was launched in field of
immunosuppressant drugs. An immunosuppressant drug restrains a transplanted
patientâ„¢s immune system to prevent rejection of the implanted organ.
Dr. Gertrude Elion developed the first with end stage cardiovascular disease
in 1957. Azathioprine proved to be useful tool that helped facilitate future
advancements in organ transplantation.
In 1967, Dr. Barnard performed the first human heart transplant
in Cape Town, South Africa. Dr. Barnard implanted the donor heart from a 25-year
old female into a 55-year old female with end stage cardiovascular disease .she
lived for 18 days with the transplanted organ. Ironically, the medication
prescribed to suppress rejection of the new organ weakened his immune system.
Current heart transplantation techniques prove to be a
viable option .According to the United Network of Organ Sharing (UNOS),
2,202 heart transplants were performed in 2001 compared to 170 transplants
performed in 1970. Currently, approximately 70% of transplant patients live for five
or more years after transplantation [UNOS, 1999]. These current statistics are
staggering in comparison to the 14% survival rate from the early 1970s.Scientists
and physicians have worked collectively to make transplantation a safe and
effective process.failure patients, there are many limitations to the procedure. As of
now more than 11,163 patients were awaiting heart transplant [UNOS, 2004]. Only
about quarter of these patients will receive a new heart [UNOS, 2004].Since
there is such a shortage of donor hearts.
Therefore, further development provides a solution for all
patients. Current development of artificial hearts strives to is necessary to provide a
universal solution for these patients.
4. Total Artificial Heart Development
The development of artificial hearts reflects a transition
from a support device to a completely self-contained machine. In the 1960s, the
purpose of an artificial heart was to temporarily support patients until a donor
heart became available. Surgeons attempted successful; however, many surgeons
became wary of this device because it early 1980s by implanting an artificial
heart intended for long-term therapy. The device they used was the Jarvik-7, a blood
pump that replaces the heartâ„¢s ventricles. The procedure was initially successful;
however, many surgeons became wary of this device because it did not offer an
acceptable quality of life. As a result, the public began to question the need
for permanently removing vital components of the heart. The world of artificial
heart technology then separated into two classes: assist devices and artificial
hearts. In the 1980s, several organizations, including Abiomed Inc., Penn State
Medical Center, and the Texas Heart Institute, began developing ideas for new
designs. Their intent was to engineer artificial hearts that could permanently
sustain heart failure patients while providing a decent quality of life. These
companies immediately encountered one huge barrier infection due to precutaneous or
skin piercing, tubes. During the 1980s, every artificial heart had power cords,
blood tubes, or air tubes protruding from skin. It was not until the early 1990s with
the advent of transcutaneous technology.
Milestones in the Artificial Heart Technology
Â¢ 1960s â€œ Surgeons implant the first temporary artificial heart.
Â¢ 1970s â€œ Engineers develop the ventricle assist device as an
to artificial heart
Â¢ 1980s â€œ First long term artificial heart results in poor quality of life.
VADâ„¢s show potential for long term support.
Â¢ 1990s â€œ Transcutaneous technology eliminates the need for skin â€œ
Protruding. Electrical wiring, patients with long-term VDAâ„¢s
recovers from heart failure.
Â¢ 2000s â€œ Results of the Abiocor reflect improved quality of life
patients after implantation.
5. A Complete Artificial Implantable Heart
This device is a permanent artificial heart that is completely self- contained
within the body. Some cases like they may have failure on both left and right side of
the heart. Before the introduction of the device, doctors had no option than to let
these patients die. However, artificial heart developers, such as Abiomed Corp. and
Penn State, focused their design parameters for patients whoâ„¢s hearts have
irreversibly failing left and right ventricles. This category of patients comprises
about 20% of those in need of a heart transplant.
Designs for this device initially began in the early 1980s, around the
time of the Jarvik-7. Only recently has the device artificial heart received. The
device. which was prepared by Abiomed with the same principle was approved
by FDA for clinical testing. The large time span for approval results from the
controversy caused by the Jarvik-7. The device design addresses key pitfalls
encountered with the Jarvik-7. Improvements include better surface materials to
reduce blood clotting and a newly engineered power system that does not require
skin piercingelectrical cords. These design considerations were applied to the new
model and clinical testing of the device made by Abiomed has begun in the recent
times. The first patient implanted with the device, was lived for nearly five months.
This event caught the attention of the public because
it was the first time a patient with an artificial heart was able to stand up and walk
around. As of patients are alive today. Today, seven people received the and two
6. Design of the Complete Artificial Implantable Heart
Three subsystems implanted under the skin make up the design of the device.
These subsystems include the heart pump, a computerized pump controller, and a
power source. All of the subsystems cumulatively,
Weigh around 4 pounds and operate so quietly that stethoscope is needed to listen to
the heart sounds. Surgeons implant the heart pump in the area from where the
ventricles are removed. Channels that connect naturally to the ventricles are then
sewn into artificial cuffs that snap on to the heart. Two independent
hydraulic motors lie inside the heart One motor maintains the pumping
function to each ventricle while the other motor operates the motion of the four
heart valves. The pumping motion operates through hydraulics by an oscillating
pusher plate that squeezes sacs which alternatively expel blood to the lungs and
the body. When the blood sacs become full, the exit valves are shut and the entrance
valves are open. The pump then squeezes the sacs, which allows the exit valves
to open and the entrance valves to close. The device is capable of producing
more than two gallons of blood every minute, which signifies a higher output
than the Ventricular assist devices(VAD). Similar in design to the VAD, a small
computer secured in the abdomen of a patient automatically adjusts the output of
the pump. The continual monitoring of blood flow guarantees that incoming flow
matches outgoing flow. This rhythm ensures steady state pumping of the heart.
The transfer of energy is also the same as in the VAD. Surgeons implant an
electric coil in the abdomen area to allow for energy transfer across the skin.
Patients wear a battery pack around the waist and must change the batteries several
times daily. The system also includes an internal battery so that patient may
uncouple the external power source in order to take a shower. One significant
advantage to the device is the smooth surface of the blood sacs. Smooth plastics
are important in order to ensure constant motion of blood cells. Any time blood
stops moving along the of the device clotting develops. The smoothness of the
plastic, called Angioflex, allows for minimal damage to the blood. Angioflex is
also durable enough to withstand 1,00,000 beats a day for several years. This
plastic is a major cont ibution to the life and to the safety of the device.
Heart failure is the leading cause of death in India and also all over the
World. Most people die from heart failure chambers, fail to push enough blood
through the body. A solution to donor heart rejection surfaced in the early 1980s
with the advent of cyclosporine an immunosuppressant and this discovery, the
average survival rate of heart transplant patients increased to more than 5 years. One
of the drawbacks to heart transplantation is its availability is only half of the
patients needing a heart transplant will receive a donor heart The development of
artificial hearts resurfaced again in 1993 with the advent of transcutaneous technology.
Transcutaneous technology is based on the transfer of
power across the skin by electric coils.This technology eliminates infection due to
skin- protruding electrical tubes. Artificial hearts and heart transplantation are
the only methods for saving the lives of patients with heart failure. As of today,
heart transplantation is the official method for replacing the human heart. But,
donor hearts are not available to all patients. Heart transplantation and artificial
hearts are not a competing source of technology. These technologies exist
parallel to each other in order to encompass the whole population of patients in
need of a new heart. Hope this technology will soon reach to the common man
in I NDIA.
. Anatomy and physiology: by Tortora and Grabowski
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15-02-2011, 05:39 PM
hello sir,plz send more details about artificial heart
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artificial heart report.doc (Size: 973 KB / Downloads: 83)
Many people suffer from heart disease. Some of the diagnosed cases are so severe that patients may not survive the wait for a donor heart. There are many devices that are available such as such as pacemakers and artificial hearts to keep patients alive until a donor heart is becomes available. Like all machines the heart can malfunction in numerous ways. Many conditions fall under the category of cardio vascular disease; but two main causes for heart transplantation and artificial hearts: coronary heart disease and congestive heart failure .The development of the artificial hearts reflects a transition from a support device to a completely self contained machine. In the 1960s the purpose of an artificial heart was for to temporarily support patients until a donor heart became available. Surgeons attempted to change this role in the early 1980s by implanting an artificial heart intended for long term therapy. The device they used was the Abiocor, a blood pump the heart ventricles. Although this procedure was successful, the surgeons became wary of this device as it did not provide an acceptable quality of life .As a result the public began to question the need for removing vital components of the heart .The world of artificial heart was then separated into two classes; assist devices & artificial hearts.
In the 1980s the organizations involved in making new designs for the artificial heart encountered one major problem, infection due to percutaneous or skin piercing tubes as every artificial heart has power cord, blood tubes or air tubes protruding from the skin .It was not until the early 1990s with the advent of transcutaneous technology that progression to permanent devices became more feasible. Today the role of artificial hearts has extended from temporarily bridging a patient to transplantation to providing long term assistance.
2. NEED FOR ARTIFICIAL HEART
The two main causes for heart transplantation and artificial hearts are coronary heart disease and congestive heart failure. Coronary heart disease (CHD) is the hardening of artery walls inside the heart .Arteries are essentially piping that connects heart valves together. In CHD, the transportation of blood becomes when a mixture of fat and cholesterol, or plaque, lines the arteries. The buildup of plaque restricts the free flow of blood, which induces a pressure drop between the valves. The heart compensates for this pressure drop by pumping harder in order to provide blood for the entire for the entire body. Patients suffering from CHD often exhibit symptoms such as severe chest pain and fatigue due to the lack of oxygenated blood. For severe cases of CHD, the only cure is a heart transplant. Congestive heart failure (CHF) arises when the heart does not efficiently pump blood .Since the heart is unable to pump enough oxygen rich blood, blood starts filling in the lungs, which leads to congestion. Therefore, the heart must work harder to meet the body’s oxygen demands. This behavior causes excessive wear of the diseased organ. Initial symptoms of CHF, such as fatigue and swelling of the ankles are usually so minor that the patients are not diagnosed until the condition becomes much more severe.
Further lack of organ donors, and availability at the right time justified the research in this field.
3. WORKING OF HUMAN HEART
The human heart pumps 10,000 liters of blood per day. Deoxygenated blood flows from the rest of the body to the right atrium. Oxygenated blood flows from the lungs to the left atrium. Deoxygenated blood flows from the right ventricle to the lungs. Oxygenated blood flows from the left ventricle to the rest of the body.
The human heart is divided into four chambers:
1. Right Atrium
2. Right Ventricle
3. Left Atrium
4. Left ventricle
The heart contracts in two stages:
1. In the first stage, the right and left atria contract at the same time, pumping blood to the right and left ventricles.
2. In the second stage, the ventricles contract together to propel blood out of the heart.
4. MILESTONES IN ARTFICIAL HEART TECHNOLOGY
1960 - Surgeon implants first temporary artificial heart.
1970 -Engineers develop the ventricle assist devices as an alternative to artificial hearts
1980 - First long term artificial hearts lead to poor quality of life.
- VAD show potential for long term support
1990 -Transcutaneous technology eliminates need for skin protruding electrical wiring
- Patients with long term VAD recover from heart failure.
2000- Results of the abiocor reflect improved quality of life for patients after implantation
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artificial_heart.ppt (Size: 844 KB / Downloads: 111)
The Artificial Heart: A Design Example
The Human Heart
Heart has four chambers
Right chambers pump blood to lungs to receive oxygen
Left chambers pump oxygenated blood from lungs to rest of the body
Right and left atria receive blood
Right and left ventricles pump blood
Valves produce one-way blood flow from atria ® ventricles ® arteries
Energy to pump blood comes from nutrients and oxygen in blood
The blood supply to the heart is provided by coronary arteries
Heart attack: blockage of coronary artery damages portion of heart muscle
Congestive heart failure: gradual weakening of heart
Millions suffer from heart disease
– Many cases are treatable with lifestyle changes, drugs and/or surgery
– Surviving patients suffering from most severe cases need new hearts!
The Need for a Heart Substitute
100,000 Americans/year suffering from severe heart disease need new hearts
Only 2,000 patients receive heart transplants
Conclusion: many patients die waiting for a new heart!
A suitable alternative to donor hearts could prolong thousands of lives
History of Heart Substitutes
WWII: first open heart surgeries
1953: heart-lung machine successfully used during heart surgery
1958: Drs. Willem Kolff and Tetsuzo Akutsu sustain a dog for 90 minutes with a PVC artificial heart
1967: Dr. Christian Barnard transplants a donor heart into a 59 year old man (he survived 18 days)
1969: Dr. Denton Cooley uses an artificial heart to sustain a patient waiting for a donor (survived 3 days)
1972: Cyclosporine introduced to suppress immune responses of transplant recipients
1982: Dr. William DeVries implants the Jarvik-7 artificial heart into Dr. Barney Clark (he survived 112 days)
Why Heart Substitutes Fail
Immune response “rejects” transplant or side effects due to immune suppression
Infection due to tubes and wires passing through skin
Formation of clots
Damage to red blood cells
Lack of pulsatile blood flow?
Identify the problem or need to address
Specify details/criteria of an adequate solution to your problem
Implement various solutions that meet the criteria you specified
Test to determine which solution is most viable
Further testing to refine the solution you chose
Process is iterative
– You need to repeat various steps after testing
– Make design changes based on test results
– Design didn’t meet criteria
– Could be due to inappropriate criteria
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