What is an Artificial Heart?

Creating an artificial heart that would be a successful longterm replacement for the human heart has been a goal in medical research for numerous decades. Thus far, various doctors and scientists have developed some machines that can take over heart function while a patient waits for a transplant, or for people who canít receive transplants. These mechanical hearts may be placed in the body, so that many people may have an extension of life, but they donít last forever.
Prior to delving into the history of the artificial heart, itís important to understand what it is and what it isnít. This mechanized device is not a heart/lung bypass machine. Such machines are a hugely important development in medicine nevertheless, and are used on a regular basis.
Artificial hearts should be viewed as distinct from ventricular assist devices and left ventricular assist devices (VADs and LVADs). These may be implanted to take over some of the work of a heart that retains a certain amount of function. They are useful too in bridging the gap when patients are on transplant waiting lists, and may help assist the heart in continuing to work at a more efficient rate for a period of time. However, it should be understood that a true artificial heart is implanted in the body and takes over the work of the failing heart. The term failing usually means that neither the left or right ventricle can function enough to support life.

In the mid-twentieth century, there were several people working on the creation of an artificial heart, and the first implant was performed on a dog in 1957. It was not tremendously successful and the dog only survived for a few hours after the implantation. Research of total mechanized hearts continued on dogs, and in the mid 1960s, doctors began to develop LVADs too, with the first successful LVAD surgery performed in 1966.

Much trial and error followed, and some of the main concerns included rejection of various components of artificial hearts, and survival rate, which was considerably low for both LVADs and total hearts. In the 1980s, two artificial hearts were developed that continue to be used. These are the Jarvik and the Abiocor. Both have been used in many surgeries to extend life. The Abiocor was considered an improvement on the Jarvik because its power source was not outside of the body. The Jarvik requires external wiring to a power source, but has proven over long clinical studies to be more effective than the Abiocor with longer survival rates for some patients.

Another artificial heart developed in the 2000s that shows great promise has been created by Dr. Alain Carpentier of France, and this heart is in trials to determine efficacy and safety. Unlike its predecessors, Carpentierís model uses some animal tissue in its design, which might prove effective in reducing rejection. Other scientists continue to work on additional models, since even though some patients survive for several years after receiving an artificial heart, others still donít. For some survivors, quality of life can be poor and length of life may be short.

There are some inherent concerns with creating artificial hearts. One that remains is how to power the heart, and improvement in various power cells may ultimately allay these concerns. Yet a human heart must work constantly and even with advanced power techniques, itís hard to know how long any artificial heart can last, once in the body. Still there remains much need for artificial hearts because some people are not eligible for heart transplants, and others need one and die waiting for a heart.

There is some speculation about whether advances in regenerative medicine would ultimately make the quest for the perfect artificial heart obsolete. Hope exists that someday scientists will be able to use a patientís own tissue to grow a new heart for those who need them. This would eliminate concern over rejection and address the issue of lack of transplants to meet demand.