A mistrial was declared yesterday in the $10 million civil lawsuit against Annandale gynecologist David K. Davoudlarian after a Fairfax County jury failed to agree whether he strangled his wife.

Circuit Judge Lewis H. Griffith dismissed the seven-member jury, which deliberated 13 hours Friday and yesterday, and said the case will be scheduled for retrial this summer.

The split on the jury was not announced in court, but jurors interviewed later said five of their number were persuaded that the doctor had killed his wife and two were unconvinced.

Davoudlarian and his attorneys were quick to claim victory.

But attorneys for the estate of Susan S. Davoudlarian, the doctor's 40-year-old wife, said the 5-to-2 split indicates the strength of their case.

Davoudlarian, 49, said as he left the courthouse: "I feel good. I've done nothing wrong. I expected to be exonerated."

The doctor, who denied on the witness stand that he killed his wife and testified that he loved her, spent much of the last three weeks in the highly unusual and closely watched trial listening to a succession of witnesses testify in detail about his marriage, his temper, his wife's extramarital affairs, his reaction to her disappearance and her death.

Plato Cacheris, one of his attorneys, said, "This was always a murder prosecution in the guise of a civil case. The fact that a civil jury couldn't agree on a verdict is a victory."

No criminal charges have ever been filed in the death of Susan Davoudlarian, whose nude body was found on June 12, 1983, wedged beneath the folded-down back seat of her station wagon parked in the long-term lot at Dulles International Airport. Civil suits have a less stringent standard of proof than criminal prosecutions.

Fairfax County prosecutor Robert F. Horan Jr., who has said there is insufficient evidence to bring criminal charges, said he encouraged the civil suit "because I thought they the estate could win . . . and because I was hopeful some things would come to light that would change our position in terms of criminal prosecution."

He said the trial had produced "nothing that changes the basic facts as we knew them before it began." Much of the evidence introduced in the civil suit would have been inadmissible in a criminal case.

Publicity surrounding the case has, however, brought in several phone calls to police with new information, Horan said. Those tips are still being investigated, he said.

Peter Greenspun, one of two attorneys who represent the estate, said when told of the jury split, "There is no way this is a victory for Davoudlarian . . . . Five people out of seven believed the doctor killed his wife, and if that's the case, we find it incredible that Dr. Davoudlarian or his attorneys could claim that to be a victory."

Stanley Klein, the other attorney for the estate, said he and Greenspun, along with the daughters and father of Susan Davoudlarian, "are looking forward to the next trial. We're ready and we're looking forward to it."

The two women, children of Susan Davoudlarian's first marriage, have filed a second civil suit that also accuses their stepfather of killing their mother and seeks to block him from collecting $750,000 in property and life insurance.

The trial of their suit will be postponed pending the outcome of the retrial of the estate's suit.

The mistrial was an especial anticlimax for the crowds of relatives, friends, attorneys, court personnel and other spectators who had watched the case over three weeks. In its final days the trial was moved to the largest courtroom in the Fairfax County Courthouse to accommodate the onlookers.

The attorneys who brought the suit presented two weeks of testimony, weaving a circumstantial case that they said clearly implicated the doctor despite the lack of any physical evidence indicating where Susan Davoudlarian was killed or by whom.

They said her love affairs and $374,000 in life insurance that the doctor purchased in the final four months of her life were reasons her husband could have killed her.

In his closing argument last Thursday, Klein said that because Susan Davoudlarian was found nude, without contact lenses or glasses, covered in a blanket taken from her home, she was probably killed in the family house at 8808 Aunt Lilly La.

Attorneys for Davoudlarian presented evidence over three days, centering on 11 hours of testimony from their client.

In his closing argument, Cacheris told the jurors that Davoudlarian is "insensitive," "an ass" and "a boor," "but not a cold-blooded strangler." He argued that if Davoudlarian killed his wife and drove her body to Dulles, he would have needed some way to return home. FBI interviews with dozens of cabdrivers and airport employes produced no evidence placing Davoudlarian at Dulles.

Jurors interviewed yesterday said the questions of where Susan Davoudlarian died and the mystery of how her body got to the airport were central in their disagreement.

"The evidence was not conclusive enough so that we could decide that she was murdered in the house or went out and got murdered," said one juror, who asked not to be identified.

Juror Arthur L. Brown declined to say how he voted, but said the majority thought Davoudlarian was "quick-tempered," had lied on the stand and believed that his wife was killed in their home.

The two jurors favoring Davoudlarian, he said, thought there were critical gaps in the case against him, including the questions of where she was killed and how the doctor might have returned from Dulles if he had taken her body there. He said they did not think the doctor had sufficient motive to kill his wife.

Brown, whose 38th birthday was yesterday, said the trial had been exhausting. "I've had three experiences in my lifetime that I'll never forget," he said, " -- when I was in Vietnam, when I was in the delivery room with my wife and this trial."