Two Soviet and American cardiologists, whose antinuclear campaign has been honored with this year's Nobel Peace Prize but denigrated by critics as politically naive, found a brief respite from controversy today by pooling their professional skills and apparently saving a heart attack victim.

At a crowded press conference on the eve of their acceptance of the prize on behalf of International Physicians for the Prevention of Nuclear War, Drs. Evgeni Chazov of the Soviet Union and Bernard Lown of the United States were fending off hostile inquiries about their group's refusal to become involved in human rights issues when a medical emergency inspired an impromptu display of East-West cooperation.

A Russian journalist had tumbled to the floor, stricken by cardiac arrest. Lown and Chazov jumped from the podium, peeled off their jackets and took turns trying to revive the patient's heart by pressing his chest, all the while shouting in Russian and English for drugs and equipment.

The journalist was rushed to an Oslo hospital, where a spokesman said the Russian was in "stable but critical condition," adding that "quick action by this year's award winners appears to have saved his life."

The two doctors were aided by several other heart specialists in attendance, who had come here to participate in the Nobel ceremonies as representatives of the organization informally known as Doctors Against Nuclear War. The group, which includes more than 135,000 members in 41 nations, was awarded this year's peace prize for its work in publicizing the medical and environmental hazards of nuclear warfare. The group has been praised by scientists as offering cogent analyses of the likely consequences wrought by explosions of nuclear weapons.

The doctors' advocacy of a nuclear test ban and a freeze on further development of all nuclear arms has brought the group into conflict with the Reagan administration's defense buildup and critics who charge the group's positions carry a pro-Soviet bias.

International outrage swelled recently when it was revealed that Chazov had signed a letter in 1973 with other Soviet doctors denouncing dissident Soviet physicist Andrei Sakharov, who won the 1975 Nobel Peace prize for his campaign against human rights violations in the Soviet Union.

Chazov refused to respond directly to questions posed today about whether he regretted signing such a letter. He and Lown argued that the efficacy of their work could only be sustained if their group avoided politically sensitive issues.

"We disagree on many aspects," Lown said. "But we have risen above the partisanship of the cold war to inform the world that this merry-go-round to oblivion must stop."

Lown contended that the doctors' group decided when it was founded in 1980 to skirt political conflicts between their rival countries by focusing solely on the scientifically proven dangers of nuclear confrontation. He complained that such groups as Amnesty International, which won the Nobel Peace Prize in 1977 for its publicizing of human rights abuses, are not faulted when they fail to address adequately nuclear and other issues.

"Broadening the agenda would break up our movement," Lown explained later in an interview. "We have found a small oasis of common interest that we pursue with obsessive intensity."

"Is the destruction of a voice of reason worth doing at the expense of leaving the world in greater ignorance about nuclear catastrophe?" he asked.

Lown said he was "appalled" by the actions taken by West German Chancelor Helmut Kohl and other conservative party leaders in Western Europe, who urged the Nobel commmittee to rescind the award because of Chazov's involvement.

"There are enormous forces around us that enjoy and profit from the cold war," Lown said. "What Kohl and others are trying to do is block us from ending the nuclear arms race."

Chazov insisted he was attending the Oslo ceremonies strictly in his capacity as a physician and cochairman of the doctors' group, not in his other roles as deputy health minister and a full member of the Communist Party's policy-making Central Committee.

When pressed in an interview on the fact that, unlike Lown, he serves not as a private physician but as a government official, Chazov said, "Perhaps it is good that a man like me has some influence within my government. I am not asking for more missiles, because that would be a bad thing."

He contended that the issue of Sakharov's freedom was "not our problem as doctors against nuclear war, because it is outside the commitment of our organization."

"Maybe if we start building confidence by halting the nuclear arms race," Chazov continued, "then some of the human issues could be quickly solved."

During today's press conference, Chazov dodged direct answers to questions concerning Soviet human rights. He insisted that the world would not be a safer place if Soviet physicians ultimately were compelled to leave the antinuclear movement because of political turmoil.

"You then might think the Soviet people do not understand the grave consequences of nuclear war," Chazov said. "But we do share this knowledge, so let us not disrupt this dialogue between the physicians."

At that point, the news conference turned chaotic as the doctors rushed to attend the heart attack victim, who was identified as Lev Novikov, a Soviet television journalist.

Laboring feverishly to resuscitate the patient, the international team applied shocks with a defibrillator and injected him with lidocaine, a drug that calms irregular heart rhythms. Several doctors later said both methods were pioneered by Lown, now professor of cardiology at the Harvard School of Public Health.

After 20 minutes of treatments, the unconscious patient was taken to a hospital, leaving Lown and the others in despair over his chances of survival. "I felt no pulse; he's probably dead," Lown said.

It was their common interest in "sudden death" by cardiac arrest -- the leading killer in the Soviet Union and the United States -- that brought Lown and Chazov together more than 15 years ago. They first began to exchange medical research findings, and developed such a close rapport that they decided five years ago to launch the crusade to banish the threat of nuclear war.

Calling the journalist's crisis "a strange parable" of their work, Lown observed that the assembled doctors responded to save a life without regard to nationality. "We do not care if the man is Russian or American," said Lown. "When crisis comes, Soviet and American cardiologists cooperate."

"We all have to die someday," Lown continued. "What we in IPPNW are trying to redress is the danger that we all may die in the same instant." Overcome by tears, he then disbanded the press conference.