While people with failed hearts wait for a transplant, they're often given a device that helps the original heart keep working until a replacement becomes available. Those devices aren't always enough to help a weakened heart, though, so researchers at the University of Arizona tested an alternative: using an artificial heart to bridge the gap between the weak, old heart until a new heart is found.

What the researchers wanted to know: Can the CardioWest Total Artificial Heart fill in until a real heart turns up?

What they did: The CardioWest is a big blood pump with a large power source on wheels, so—in the United States—you have to stay in the hospital while you're on it (in Europe, there are portable consoles that allow patients to be sent home). The study used 130 patients at five institutions. Ninety-five got artificial hearts, although only 81 really qualified for the study. (Many of the remaining 14 were unlikely to survive much longer but were given artificial hearts anyway out of compassion.) The 35 controls were used only to compare survival rates; the researchers just studied their records for a general idea of what usually happens to patients with failed hearts.

What they found: Almost 80 percent of the 81 patients who qualified and got an artificial heart survived long enough to get a heart transplant, compared with 46 percent of controls. One week after their artificial hearts were plugged in, 75 percent of patients were out of bed. Many patients bled enough to need major transfusions either while the artificial heart was being inserted or soon after, and two died from that bleeding. One more died when the heart malfunctioned, and two more died partly because their hearts didn't fit right.

What the study means to you: The artificial heart has risks, but patients with artificial hearts were much better off than patients studied as controls, many of whom died from heart failure or cardiac arrest.

Caveats: The study was funded by the company that makes the artificial heart. That company, SynCardia Systems, also pays two of the study's authors for part-time work, and they and one other author own stock in the company.

Find out more: Organs aren't automatically donated after death; you have to sign up to be an organ donor and tell your family about your wishes. Find out how to sign up in your state: www.shareyourlife.org/

SynCardia has a picture of the heart on its home page: www.syncardia.com

Read the article: Copeland, J.G. et al. "Cardiac Replacement With a Total Artificial Heart as a Bridge to Transplantation." New England Journal of Medicine. Aug. 26, 2004, Vol. 351, No. 9, pp. 859–867.

Abstract online: http://content.nejm.org