Bethesda Naval Hospital has halted heart surgeries after an internal review committee refused to approve the new head of its cardiothoracic unit -- an Army doctor assigned to replace Navy Cmdr. Donal M. Billig, now charged with the involuntary manslaughter of five patients there.

Col. Michael Barry, the former assistant chief of cardiothoracic surgery at Letterman Medical Center in San Francisco, was assigned to Bethesda July 1, about two weeks after Billig was recommended for general court martial. Barry was given temporary privileges for three months but was told Friday that Navy doctors "did not feel they had sufficient opportunity to assess his performance" to approve him for full privileges, Navy spokesman Lt. Stephen Pietropaoli said.

Army spokesmen said yesterday that the review committee's decision came after a resident at Bethesda questioned how Barry "handled tissues." Navy spokesmen refused to comment on that information.

Barry "declined a request" from Bethesda Commanding Officer Capt. Steven Amis to extend his temporary status. He instead was assigned to Walter Reed Army Medical Center, according to Navy and Army spokesmen.

Barry, who said yesterday he did not want to comment on the matter, has been given temporary privileges and will be supervised during operations for the next three months, Army spokesmen said.

Barry's departure leaves Bethesda with two staff cardiothoracic surgeons, including newly appointed acting head Dr. Charles Lee, who is on a two-week leave. Two heart operations that had been scheduled during the next two weeks have been postponed and any emergency heart cases will be referred to other military hospitals, Pietropaoli said. The Navy would not say yesterday when heart surgery will be resumed.

Maj. Gen. Lewis Mologne, commander of Walter Reed Army Medical Center, yesterday described Barry as "a very competent, conscientious, qualified surgeon." He said the Navy had assured him Barry had "no untoward events or concerns with morbidity or mortality that led to" the Bethesda's decision to withhold full credentials.

"With all of the publicity with the Dr. Billig saga, they [Bethesda officials] would understandably be very sensitized to scrutinizing everything down to the finest detail," Mologne said. "One of the residents there had expressed concern over how Dr. Barry handled tissue . . . and this led to the reservations about the credentials . . . "In this day and age, I can well appreciate their concern."

Navy officials would not elaborate yesterday on the need for Bethesda doctors to review Barry's work further. Of the 127 patients operated on during the last nine months by the cardiothoracic surgeons at Bethesda, two have died, said Navy spokesmen who declined to elaborate.

Barry's assignment to Bethesda was a standard procedure, Navy spokesmen said, and part of a cooperative effort maintained by the services whenever staff shortages occur. Barry, a 20-year veteran and a board-certified surgeon in general and cardiothoracic surgery, had been at Letterman Medical Center for six years when he agreed to replace Billig earlier this year.