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 might 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 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. (A heart transplant is surgery to remove a person's diseased heart and replace it with a healthy heart from a deceased donor.)
You might 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 chambers—the 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, go to the Health Topics How the Heart Works article.)
Currently, the two types of TAHs are 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, run from inside the chest to an outside power source.
Normal Heart and CardioWest Total Artificial Heart
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
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. A TAH 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.
- Artificial heart
You might 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. TAHs aren’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 U.S. 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.
Before you get a total artificial heart (TAH), you’ll 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’ll 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 they think your body is too weak, you may need to get extra nutrition through a feeding tube before the surgery.
You also will have tests to make sure you're ready for the surgery. These tests include:
- A chest CT scan. This test is used to make sure the TAH, which is fairly large, will fit in your chest. 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.
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 might 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 bypass 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 well
Before the surgery, you're given medicine 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 supports breathing).
A cut is made down the center of your chest. The chest bone is then cut and your ribcage is opened so the surgeon can reach your heart.
Medicines are used to stop your heart. This allows the surgeons to operate on your heart while it's still. A heart-lung bypass machine keeps oxygen-rich blood moving through your body during surgery.
Heart-Lung Bypass Machine
The surgeons remove your heart's ventricles and attach the TAH to the upper chambers of your heart. When everything is properly attached, the heart-lung bypass machine is switched off and the TAH starts pumping.
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 supports breathing) 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. You’ll 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, the feeding and urine tubes will be removed. You’ll be able to go to the bathroom on your own and have a regular diet. 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 you when you go home.
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 safe for you.
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’ll 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 of infections.
You’ll 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, also called a driver. The driver is portable, so you’ll be able to walk around and do activities.
Nutrition and Exercise
While you recover from TAH surgery, it's very important to get good nutrition. Talk with your health care team about following a proper eating plan for recovery.
Your health care team may recommend a supervised exercise program. Exercise can 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.
You'll have regular checkups with your health care team. The team will want to check your progress and make sure your TAH is working well.
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 in person.
The CardioWest TAH can't be checked remotely.
Your health care team will explain warning signs to watch for. If these signs occur, or if you start feeling sick, you'll need to see your doctor right away.
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.
You’ll 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. A 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.
If you're on the waiting list for a heart transplant, you'll likely be in close contact with the transplant center. Most donor hearts must be transplanted within 4 hours after removal from the donor.
The transplant center staff may give you a pager so they 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.
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. Talk about how you feel with your health care team. Talking to a professional counselor also can help. If you’re very depressed, your doctor may recommend medicines or other treatments that can improve your quality of life.
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.
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 poorly 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’ll 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.
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 anticlotting medicine for as long as you have a TAH.
The surgery to implant a TAH is very complex. Bleeding can occur in your chest during and after the surgery.
Anticlotting medicine also raises your risk of bleeding because it thins your blood. Balancing the anticlotting medicine with the risk of bleeding can be hard. Make sure to take your medicine exactly as your doctor prescribes.
One of the two available TAHs, the CardioWest, attaches to a power source outside your body through holes in your abdomen. These holes increase the risk of bacteria getting in and causing an infection.
With permanent tubes running through your skin, the risk of infection is serious. You’ll need to take medicine to try to prevent infections.
Your health care team will watch you very closely if you have any signs of infection, such as a fever. You may need to check your temperature several times a day as part of your ongoing care.
With both types of TAH, you’re at risk for infection after surgery. Your doctor will prescribe medicine to reduce the risk.
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 well
This doesn't mean a TAH is bound to fail. In fact, TAHs that have been implanted in people in recent years have generally worked very well. However, problems with the device can occur.
The National Heart, Lung, and Blood Institute (NHLBI) leads or sponsors many studies aimed at preventing, diagnosing, and treating heart, lung, blood, and sleep disorders.
Related Health Topics
- FDA Approval of First Totally Implanted Permanent Artificial Heart (NHLBI News Release, September 5, 2006)
- Artificial Heart (MedlinePlus)