What Is a Total Artificial Heart?
A total artificial heart (TAH) is a device that
replaces the two lower chambers of the heart. These chambers are called
ventricles (VEN-trih-kuls). You may benefit from a TAH if both of your
ventricles don't work due to end-stage
heart
failure.
Heart failure is a condition in which the heart is
damaged or weakened and can't pump enough blood to meet the body's needs. "End
stage" means the condition has become so severe that all treatments, except
heart
transplant, have failed.
Overview
You may need a TAH for one of two reasons:
- To keep you alive while you wait for a heart
transplant
- If you're not eligible for a heart transplant,
but you have end-stage heart failure in both ventricles
The TAH is attached to your heart's upper
chambersthe atria (AY-tree-uh). Between the TAH and the atria are
mechanical valves that work like the heart's own valves. Valves control the
flow of blood in the heart. (For more information, see the Diseases and
Conditions Index
How
the Heart Works article.)
Currently, there are two types of TAH. They're known
by their brand names: the CardioWest and the AbioCor. The main difference
between these TAHs is that the CardioWest is connected to an outside power
source and the AbioCor isn't.
The CardioWest has tubes that, through holes in the
abdomen, connect from inside the chest to an outside power source.
Normal Heart and CardioWest Total
Artificial Heart
Figure A shows the normal anatomy
and location of the heart. Figure B shows a CardioWest TAH. Tubes exit the body
and connect to a machine that powers and controls how the CardioWest TAH
works.
The AbioCor TAH is completely contained inside the
chest. A battery powers this TAH. The battery is charged through the skin with
a special magnetic charger.
Energy from the external charger reaches the
internal battery through an energy transfer device called transcutaneous energy
transmission, or TET.
An implanted TET device is connected to the
implanted battery. An external TET coil is connected to the external charger.
Also, an implanted controller monitors and controls the pumping speed of the
heart.
Normal Heart and AbioCor Total
Artificial Heart
Figure A shows the normal anatomy
and location of the heart. Figure B shows an AbioCor TAH and the internal
devices that control how it works.
Overview
A TAH usually extends life for months beyond what is
expected with end-stage heart failure. If you're waiting for a heart
transplant, a TAH can keep you alive while you wait for a donor heart. It also
can improve your quality of life. However, a TAH is a very complex device. It's
challenging for surgeons to implant, and it can cause complications.
Currently, TAHs are used only in a small number of
people. Researchers are working to make even better TAHs that will allow people
to live longer and have fewer complications.
Other Names for a Total Artificial Heart
- Artificial heart
- AbioCor
- CardioWest
Who Needs a Total Artificial Heart?
You may benefit from a total artificial heart (TAH)
if both of your ventricles don't work due to end-stage
heart
failure.
If you're waiting for a
heart
transplant, a TAH can help you survive longer. It also can improve your
quality of life. If your life expectancy is less than 30 days and you're not
eligible for a heart transplant, a TAH may extend your life beyond the expected
30 days.
A TAH is a "last resort" device. This means only
people who have tried every other type of treatment, except heart transplant,
can get it. The TAH isn't used for people who may benefit from medicines or
other procedures.
TAHs also have a size limit. These devices are
fairly large and can only fit into large chest areas. Currently, no TAHs are
available that can fit into children's chests. However, researchers are trying
to make smaller models.
The United States Food and Drug Administration (FDA)
has approved the TAH for certain types of patients. Your doctor will discuss
with you whether you meet the conditions for getting a TAH.
If you and your doctor decide that a TAH is a good
option for you, you also will discuss which of the two types of TAH will work
best for you.
What To Expect Before Total Artificial Heart
Surgery
Before you get a total artificial heart (TAH), you
will likely spend at least a week in the hospital to prepare for the surgery.
You might already be in the hospital getting treatment for
heart
failure.
During this time, you will learn about the TAH and
how to live with it. You and your loved ones will spend time with your
surgeons, cardiologist (heart specialist), and nurses to make sure you have all
the information you need before surgery. You can ask to see what the device
looks like and how it will be attached inside your body.
Your doctors will make sure that your body is strong
enough for the surgery. If your doctors think your body is too weak, you may
need to get extra nutrition through a feeding tube before surgery.
You also will have tests to make sure you're ready
for surgery. These tests include:
- A
chest
CT scan. This test is used to make sure the TAH will fit in your chest.
Current TAHs are fairly large. Before you have surgery, your doctor will make
sure there's enough room in your chest for the device.
- Blood
tests. These tests are used to check how well your liver and kidneys are
working. Blood tests also are used to check the levels of blood cells and
important chemicals in your blood.
- Chest
x ray. This test is used to create pictures of the inside of your chest to
help your doctors prepare for surgery.
- EKG
(electrocardiogram). This test is used to check how well your heart is working
before the ventricles are replaced by the TAH.
What To Expect During Total Artificial Heart
Surgery
Total artificial heart (TAH) surgery is complex and
can take between 5 and 9 hours. It requires many experts and assistants. As
many as 15 people may be in the operating room during surgery.
The team for TAH surgery includes:
- Surgeons who do the operation
- Surgical nurses who assist the surgeons
- Anesthesiologists who are in charge of the
medicine that makes you sleep during surgery
- Perfusionists who are in charge of the heart-lung
machine that keeps blood flowing through your body while the TAH is put in your
chest
- Engineers who are trained to assemble the TAH and
make sure it's working properly
Before the surgery, you're given anesthesia
(an-es-THE-ze-ah) to make you sleep. During the surgery, the anesthesiologist
checks your heartbeat, blood pressure, oxygen levels, and breathing. A
breathing tube is placed in your windpipe through your throat. This tube is
connected to a
ventilator
(a machine that helps you breathe).
A cut is made down the center of your chest. The
chest bone is then cut and your ribcage is opened so that the surgeon can get
to your heart.
Medicines are used to stop your heart. This allows
the surgeon to operate on your heart while it's not beating. A
heart-lung
machine keeps oxygen-rich blood moving through your body.
The surgeons remove your heart's ventricles and
attach the TAH to the upper chambers of your heart. When everything is attached
properly, the heart-lung machine is switched off and the TAH starts
pumping.
What To Expect After Total Artificial Heart
Surgery
Recovery in the Hospital
Recovery time after total artificial heart (TAH)
surgery depends a lot on your condition before the surgery.
If you had severe
heart
failure for a while before getting the TAH, your body may be weak and your
lungs may not work very well. Thus, you may still need a
ventilator (a machine that helps you
breathe) after surgery. You also may need to continue getting nutrition through
a feeding tube.
Your hospital stay could last a month or longer
after TAH surgery.
Right after surgery, you'll be in the hospital's
intensive care unit. An intravenous (IV) line will be inserted into a vein in
your arm to give you fluids and nutrition. Youll also have a tube in your
bladder to drain urine.
After a few days or more, depending on how quickly
your body recovers, you'll move to a regular hospital room. Nurses who have
experience with TAHs and similar devices will take care of you.
The nurses will help you get out of bed, sit, and
walk around. As you get stronger, you'll be able to go to the bathroom and have
a regular diet. The feeding and urine tubes will be removed. You'll also be
able to take a shower. You'll learn how to do this while taking care of your
TAH device.
Nurses and physical therapists will help you gain
your strength through a slow increase in activity. You'll also learn how to
care for your TAH device at home.
Having family or friends visit you at the hospital
can be very helpful. They can help you with various activities. They also can
learn about caring for the TAH device so they can help when you go home.
Going Home
Activity Level
When you go home after TAH surgery, you'll likely be
able to do more activities than you could before. You'll probably be able to
get out of bed, get dressed, and move around the house. You may even be able to
drive. Your health care team will advise you on the level of activity that's
right for you.
Bathing
If you have an AbioCor TAH, you can shower or swim,
as long as the device is charged.
If you have a CardioWest TAH, you will have tubes
connected to a power source outside of your body. The tubes go through an
opening in your skin. This opening can let in bacteria and increase your risk
for infections.
You will need to take special steps before you bathe
to make sure the tubes going through your abdomen don't get wet. Your health
care team will explain how to do this.
Caring for the TAH
If you have an AbioCor TAH, you'll need to keep it
charged with its magnetic charger. When it's charged, you can do activities
that feel comfortable to you (as your doctor advises).
If you have a CardioWest TAH, it will be attached to
an external power source, or driver. The driver is portable, so you can walk
around and do activities with it.
Nutrition and Exercise
While you recover from TAH surgery, it's very
important to get good nutrition. Talk to your health care team about following
a proper eating plan for recovery.
Your health care team may recommend a supervised
exercise program. Exercise is very important to give your body the strength it
needs to recover.
During the months or years when your heart wasn't
working well (before surgery), the muscles in your body weakened. Building up
the muscles again will allow you to do more activities and feel less tired.
Ongoing Care
You'll have regular appointments with your health
care team. The team will want to check your progress and make sure your TAH is
working properly.
If you have an AbioCor TAH, your health care team
can check it remotely. This means that if you think something is wrong, you can
hook up the device to a computer with Internet access.
The computer will transfer data to your health care
team so they can see how your TAH is working. Certain problems may require you
to see your doctor to have them fixed.
The CardioWest TAH can't be checked remotely.
With both types of TAH, your health care team will
explain warning signs. If these signs occur, or if you start feeling sick,
you'll need to see your doctor right away.
Cardiac Rehab
Your health care team may recommend
cardiac
rehabilitation (rehab). This is a medically supervised program that helps
improve the health and well-being of people who have heart problems.
Rehab programs include exercise training, education
on heart healthy living, and counseling to reduce stress and help you return to
a more active life.
Medicines
You will need to take medicine to prevent dangerous
blood clots for as long as you have a TAH. Regular
blood
tests will show whether the medicine is working.
You also will need to take medicine to try to
prevent infections. Your doctor may ask you to take your temperature every day
to make sure you don't have a fever. Fever can be a warning sign of
infection.
Make sure to take all your medicines as prescribed
and report any side effects to your doctor.
Heart Transplant
If you're on the waiting list for a
heart
transplant, you'll likely be in close contact with the transplant center.
This is because most donor hearts must be transplanted within 4 hours after
removal from the donor.
Some heart transplant centers give you a pager so
the center can contact you at any time. You need to be prepared to arrive at
the hospital within 2 hours of being notified about a donor heart.
Emotional Issues
Getting a TAH may cause fear, anxiety, and stress.
If you're waiting for a heart transplant, you may worry that the TAH won't keep
you alive long enough to get a new heart. You may feel overwhelmed or
depressed.
All of these feelings are normal for someone going
through major heart surgery. It's important to talk about how you feel with
your health care team. Talking to a professional counselor also can help. If
you're feeling very depressed, your health care team or counselor may prescribe
medicines to make you feel better.
Support from family and friends also can help
relieve stress and anxiety. Let your loved ones know how you feel and what they
can do to help you.
What Are the Risks of a Total Artificial
Heart?
Getting a total artificial heart (TAH) involves some
serious risks. These risks include blood clots, bleeding, infection, and device
malfunctions. Because of these risks, only a small number of people currently
have TAHs.
There's a small risk of dying during TAH surgery.
There's also a small risk that your body may respond badly to the medicine used
to put you to sleep during the surgery. However, most patients survive and
recover from TAH surgery.
If you're eligible for a TAH, you will work with
your doctor to decide whether the benefits of the device outweigh the
risks.
Researchers are working to improve TAHs and lessen
the risks of using these devices.
Blood Clots
When your blood comes in contact with something that
isn't a natural part of your body, such as a TAH, it tends to clot more than
normal. Blood clots can disrupt blood flow and may block blood vessels leading
to important organs in the body.
Blood clots can lead to severe complications or even
death. For this reason, you need to take medicine to prevent dangerous clotting
(anticlotting medicine) for as long as you have a TAH.
Bleeding
The surgery to implant a TAH is very complex. There
are many places in your chest where you could develop bleeding during and after
the surgery.
The amount of anticlotting medicine you take also
raises your risk for bleeding. Balancing the anticlotting medicine with the
risk of bleeding can be hard. Make sure to take your medicine exactly as your
doctor prescribes.
Infection
One of the two available TAHs, the CardioWest,
attaches to a power source outside your body through holes in your abdomen. Any
time you have a hole in your skin, it increases the risk of bacteria getting in
and causing an infection.
With permanent tubes connected to the outside
through your skin, this risk for infection is serious. You will need to take
medicines to try to prevent infections.
Your health care team will need to watch you very
closely if you have any signs of infection, such as fever. You may need to
check your temperature several times a day as part of your ongoing care.
With both types of TAH, there's a risk for infection
after surgery. Your doctor will prescribe medicine to reduce the risk.
Device Malfunctions
Because TAHs are so complex, they can malfunction
(not work properly) in different ways. A TAH's:
- Pumping action may not be exactly right
- Power may fail
- Parts may stop working properly
This doesn't mean a TAH is bound to fail. In fact,
those that have been implanted in people in recent years have generally worked
very well. However, problems with how well a TAH works can occur.
Key Points
- A total artificial heart (TAH) is a device that
replaces the two lower chambers of your heartthe ventricles. You may
benefit from a TAH if both of your ventricles don't work due to end-stage
heart
failure.
- You may need a TAH to keep you alive while you
wait for a
heart
transplant. Or, you may need a TAH if you're not eligible for a heart
transplant, but you have end-stage heart failure in both ventricles.
- The TAH is attached to your heart's upper
chambersthe atria. Between the TAH and the atria are mechanical valves
that work like the heart's own valves.
- Currently, there are two types of TAH: the
CardioWest and the AbioCor. The CardioWest has tubes that, through holes in the
abdomen, connect from inside the chest to an outside power source. The AbioCor
is completely contained inside the chest and powered by a battery. The battery
is charged through the skin with a special magnetic charger.
- A TAH usually extends life for months beyond what
is expected with end-stage heart failure. If you're waiting for a heart
transplant, a TAH can keep you alive while you wait for a donor heart. It also
can improve your quality of life.
- A TAH is a "last resort" device. Only people who
have tried every other type of treatment, except heart transplant, can get it.
The TAH isn't used for people who may benefit from medicines or other
procedures.
- Before you get a TAH, you will likely spend at
least a week in the hospital to prepare for the surgery. During this time, you
will learn about the TAH and how to live with it. Your doctors will make sure
your body is strong enough for the surgery.
- TAH surgery is complex and can take between 5 and
9 hours. Before the surgery, you're given medicine to make you sleep. A cut is
made down the center of your chest and your ribcage is opened. The surgeons
remove your heart's ventricles and attach the TAH to the upper chambers of your
heart.
- Recovery time from TAH surgery depends a lot on
your condition before the surgery. Your hospital stay could last a month or
longer after the TAH surgery. While you recover, it's very important to get
good nutrition and ongoing care, and to follow your doctor's medical
advice.
- Getting a TAH involves some serious risks. These
risks include blood clots, bleeding, infection, and device malfunctions. If
you're eligible for a TAH, you will work with your doctor to decide whether the
benefits of the device outweigh the risks.
- Researchers are working to make better TAHs that
will allow people to live longer and have fewer complications.
Links to Other Information About Total Artificial
Heart
NHLBI Resources
Non-NHLBI Resources
Clinical Trials
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