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 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, 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.

September 2008