In the 21st century, the use of artificial hearts will become a commonly accepted therapy for irreversible heart disease or heart attacks, said Dr. Don B. Olsen, director of the University of Utah Institute for Biomedical Engineering.

"People will be returned to society as productive workers and participants in social institutions and their families," Olsen said.The devices of the 21st century will be a far cry from the device that kept Barney Clark alive for 122 days in 1982-83. They will be fully implantable, most likely electrically powered, and may feature a variety of designs other than the valve-and-diaphragm models now being used as bridges to transplants. Continuous-flow models could eliminate the familiar throbbing heartbeat for some patients.

The U. is one of four institutions currently working on fully implantable hearts under sponsorship of the National Institutes of Health. Research is going forward on several fronts, including work toward a storage battery that would be a dependable power source for at least five years, but compact enough to fit in the chest along with the rest of the heart.

Promising research on thermal energy engines that could convert heat to mechanical energy may provide an answer of a different sort. Nuclear-powered hearts were an objective of earlier U. research, but "society won't tolerate it," Olsen said.

Parallel research toward even better, more biocompatible materials, better control of coagulation factors and means to keep infections under control also will contribute to the success of permanent implantation, Olsen said.

"Some of the polymers we've used have an unusual propensity to certain bacteria that adhere to them," he said. For some reason, these bacteria seem protected from the body's usual defense mechanisms and are more resistant to antibiotics. Fully implantable hearts that leave no openings as access for germs will also help resolve that problem.

The U. also is working with the Ottawa Heart Institute in Canada to develop a better left ventricular assist device. In the future, improved models of assist devices will aid patients whose own hearts only need a rest, not replacement, he said.

The prospects of implantable hearts or partial hearts hold hope for a large number of people. In 1987, the American Heart Association reported that heart disease remains the leading killer of Americans. In 1984, based on provisional statistics, cardiovascular disease killed 986,400 Americans. Costs associated with the disease were estimated at $85.2 billion.

Although transplantation is a better alternative, only 2,000 donor hearts become available each year. Olsen estimates 35,000 to 50,000 people in this country alone could benefit from an artificial heart as the next best solution.