The artificial heart, a 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 is to lower the demand for heart transplants, which (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 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.
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 artificial heart will be a reality sometime in the 21st century.