A Soviet immigrant now working as a doctor in Florida was reunited with her dissident husband Tuesday after eight years of separation by superpower politics.

Pyatras Pakenas, 55, who received his Soviet passport last Wednesday, arrived at Dulles International Airport near Washington, D.C., at 4:50 p.m. EDT.His wife, Dr. Galina Vileshina, said upon being reunited with her husband, "God bless America."

After the reunion, Pakenas and Vileshina both kissed an American flag and Pakenas thanked Sen. Bob Graham, D-Fla., and Rep. E. Clay Shaw, Jr., R-Fort Lauderdale, for "the happiest day of my life."

"I really don't believe right now that it's happened," Vileshina said. "But when I saw him I said, maybe it's real, maybe it's not a dream."

Vileshina and Pakenas were scheduled to spend Tuesday night in the nation's capital and be guests of honor Wednesday at a reception on Capitol Hill.

The couple planned to return to south Florida Thursday.

Vileshina, a neurologist who lives in Boca Raton, has fought for Pakenas' emigration since arriving in the United States with her daughter eight years ago. Her lobbying with the Congress and administration, including 15 trips to Washington, gradually won support from lawmakers and the media.

Vileshina watched in vain as other divided couples were reunited, until her husband was finally granted a visa the day before President Reagan met Soviet leader Mikhail Gorbachev in Moscow last month.

Vileshina said her husband's letters helped sustain her during her fight.

"Only (Pakenas) gave me the support," she said. "He always, in every letter, said everything would be OK. I knew he would hold me in his heart always."

Vileshina and her husband applied for exit visas from the Soviet authorities in 1978, but only she won permission - in 1980 - to depart, which she did with her daughter. Their first home was in New York City.

The Pakenas-Vileshina reunion is the last of 36 cases whose cause was championed by the Divided Spouses Coalition, formed in 1985 to win freedom for husbands and wives kept apart by U.S. and Soviet politics.

"She really didn't give up, and it was tough on her," said Orest Deychak of the Helsinki Commission in Washington, D.C., a human rights group. "Her level of commitment is phenomenal. This case is a result of a lot of concerted effort - government, media, public groups, diplomats. Her story touched a lot of people."