Science Fair Project Encyclopedia
Artificial heart
An artificial heart is a device that is implanted into the body to replace the original biological heart. It is distinct from a cardiac pump, which is an external device used to provide the functions of both the heart and the lungs. Thus, the cardiac pump need not be connected to both blood circuits. Also, a cardiac pump is only suitable for use not longer than a few hours, while for the artificial heart the current record is 17 months.
This synthetic replacement for an organic mammalian heart (usually human), remains one of the long-sought Holy Grails of modern medicine. Although the heart is conceptually a simple organ (basically a muscle that functions as a pump), it embodies complex subtleties that defy straightforward emulation using synthetic materials and power supplies. The obvious benefit of a functional artifical heart would be to lower the need for heart transplants, because the demand for donor hearts (as it is for all organs) always greatly exceeds supply.
Early attempts prior to Robert Jarvik with his Jarvik-7 were disappointing; hosts died within hours or days and/or suffered massive foreign-body rejection problems. Jarvik's human designs were more impressive but his patients succumbed as well, his first Jarvik-7 patient 61-year-old retired dentist Barney Clark survived for 112 days after it was implanted at the University of Utah on December 2, 1982. Another problem is that an artificial heart requires an external power supply such as a battery pack worn on the patient's waist; no design so far has been able to use the body's own natural biological energy.
On July 2, 2001, Robert Tools received the first completely self-contained artificial heart transplant at Jewish Hospital in Louisville, Kentucky. It is called the AbioCor Implantable Replacement Heart. Tom Christerson survived for 17 months after his artificial heart transplant, the current record.
Most doctors are confident that with increased understanding of the heart and continuing improvements in prosthetics engineering, computer science, electronics, battery technology, fuel cells, etc. that the practical artificial heart will be a reality sometime in the 21st century.
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