The bloom is off the artificial heart. Hailed as a medical miracle three years ago, the artificial heart is beset by growing doubts about its use as a permanent substitute for an irreparably diseased heart. Many experts now see its role not as a permanent replacement, as originally hoped, but as a temporary "bridge" to keep a patient alive until a transplantable heart is found.

A Food and Drug Administration advisory panel last month recommended that the artificial heart program be continued, but under tighter federal oversight, including case-by-case review by the FDA.

None of the five patients whose hearts have been "permanently" replaced with the Jarvik-7 artificial heart has done well. Three are dead, including Barney Clark, the first recipient, who survived for 112 days. Two others have suffered disabling strokes that appear to be related to the artificial heart itself.

William J. Schroeder, the longest-living survivor of an artificial heart implant, was readmitted to Humana Hospital-Audubon in Louisville in November after suffering his third stroke since his operation a year earlier. He is chronically weak, tired, listless and forgetful, and speaks with difficulty.

The Jarvik-7 device is a polyurethane-and-aluminum pump powered by a refrigerator-sized machine. Some question the quality of a life that must remain tethered to such a machine. Other critics say the operation's medical complications and huge cost -- about $150,000 per case -- outweigh its benefits. Even Barney Clark's son has expressed doubts about whether his father's pioneering surgery was worthwhile.

Dr. William DeVries, who has implanted four Jarvik-7 devices in patients at the University of Utah Medical Center and at Humana-Audubon, has not performed a heart implant since April. But he said in November that he was ready to proceed with three more implants as soon as suitable candidates are found.

Other surgeons who implanted artificial hearts this year say they will wait for improvements in the device before using it as a permanent heart replacement.

Patients in four U.S. medical centers -- in Tuscon, Pittsburgh, Hershey, Pa., and Minneapolis -- received artificial hearts this year as a temporary measure before a heart transplant. The Minneapolis case involved the first woman to receive a heart implant.

One of the two Arizona patients received a device known as the Pheonix heart in March after a heart transplant failed; he died after a second transplant. The other is alive after a transplant following implantation of a Jarvik-7 heart in August. In the Pittsburgh case, a man lived for five days on the Jarvik-7 heart before receiving a heart transplant. The Hershey patient received a heart transplant after 11 days on an artificial heart, but he died 17 days later, of circulatory failure attributed to infection.

Another patient, at Karolinska Hospital in Stockholm, received a Jarvik-7 heart in April, when he was too ill to undergo a transplant. He died in November before a transplant could be done. But Dr. Bjarne Semb, who performed the operation, said the device enabled the patient gradually to regain enough strength to be considered a candidate for a heart transplant.

"What this tells us," Semb told a recent conference here, "is that the artificial heart can play a useful role in enabling patients who might otherwise die to recover sufficiently so that they can become candidates for a natural organ transplant."

Dr. Robert Jarvik, president of Symbion Inc. and designer of the Jarvik-7, is working on a new model to correct defects that may have led to medical complications and to make it even smaller -- so that it can be used more readily in women.