Doctors at a University of Arizona teaching hospital yesterday implanted a new type of temporary artificial heart in a dying 32-year-old man while they tried to locate a human heart for transplant.

A hospital spokesman said a human donor heart was located late last night and flown to Tucson, where early today surgeons reportedly were attempting another transplant.

Dr. Allan Beigel, a university vice president and spokesman for the University Medical Center hospital, said last night that the mechanical device, designed by a Chinese dentist, "had not been tested in humans" and does not have government approval, but was implanted anyway because "the alternative was that the patient would die."

The recipient, identified only as a Caucasian divorced father of two, had rejected a human heart transplant earlier in the day and had been placed on a heart-lung machine. Beigel said time was of the utmost concern because the patient was reaching the point where continued use of the machine risked causing irreparable damage.

The patient was reported in critical but stable condition after the three-hour implant procedure, which has not been approved by the federal Food and Drug Administration. Asked at a news briefing last night whether FDA approval was needed for the operation, Dr. Jack Copeland, head of the hospital's heart-transplant team, said: "Ideally, they should have, but you can't think of everything."

Later, he added, "We did not set out to do a human experiment. We set out to do a heart transplant. We were faced with a patient who had no alternative except death."

The mechanical heart used, called the Phoenix heart, was developed at St. Luke's Hospital in Phoenix, where it has been under study for about two years, Beigel said. It was one of three devices -- including the Jarvik-7 artificial heart, which has been implanted into three permanent artificial-heart recipients -- rushed to Tucson when the patient's condition began deteriorating.

An FDA spokesman said last night that the agency had informed the university yesterday that federal permission was needed for human experimentation with unproven medical devices, but that the university failed to obtain the approval.

University spokesman Mike Letson said "there was not time" to obtain permission, adding, "The legal ramifications will have to come along later."

FDA spokesman David Duarte said the agency "is waiting to hear the facts from the university." He said the FDA response could range from a reprimand to taking the matter to court.

When the patient, who had a history of severe heart disease and heart irregularities, suffered cardiac arrest early Wednesday after his transplant, he was manually resuscitated and put on the heart-lung bypass machine, Beigel said.

When a new human heart was not immediately available, Copeland sought help from developers of the Phoenix heart and officials at the University of Utah, where Barney B. Clark received the first Jarvik-7 permanent artificial heart in 1983.

Two experimental devices -- the Phoenix heart and a heart pump called the left ventricular assist device -- were sent from Phoenix. A Jarvik-7 artificial heart and an assistance team were sent from the University of Utah, but did not arrive until the implant was under way.

The Phoenix heart was selected because "apparently the condition of the patient's transplanted heart was such that it would not support" the ventricular assist device, Beigel said.

A St. Luke's Hospital spokesman said the Phoenix heart has been tested successfully in two calves but "we did not expect it to be put in a human for a while."

Temporary artificial hearts have been implanted in humans on at least three other occasions. The first trial was made by Texas cardiac surgeon Dr. Denton Cooley in 1969, the second was in Argentina in 1980, and the third was in 1981, also by Cooley.