Barney B. Clark probably would be living today with his artificial heart if he hadn't smoked for 25 years, his widow said.

"I feel that his lungs more than any other thing had to do with his ultimate death. I think his doctors would agree with me," Una Loy Clark said in an interview. In the weeks before his death on March 23 at the University of Utah Hospital in Salt Lake City, "He said many times, 'I wish I hadn't smoked,' " Mrs. Clark recalled.

Clark died at 62 after 112 days with the world's first permanent artificial heart beating in his chest. The heart still was working, but his lungs and other deteriorated organs had given out.

Weeks before his death, while talking with his wife about going home, the retired dentist "mentioned that he didn't think his lungs would ever allow him to leave the hospital. He told me, 'I need to be on a respirator.'

"I said, 'Honey, let's just hope that things will work out.' But I had the same fear. I was beginning to doubt very seriously at that point," she said.

She and her husband put the blame on a quarter century of smoking a pack of cigarettes a day, a habit he acquired while serving as an Air Corps bombardier during World War II and which he gave up 12 years before his death.

Thursday, as a new recruit in the war on smoking, Mrs. Clark is scheduled to testify on behalf of the American Lung Association on an anti-smoking education bill before the Senate Labor and Human Resources Committee. The bill would require rotating warning labels on cigarette packages as well as disclosure to the government of chemical additives in cigarettes.

She has chosen this new role, she said, to help encourage young people not to start smoking. Although the Clarks did not conceal his smoking, "we didn't go around broadcasting it. We weren't proud of it," she said in a telephone conversation from her Des Moines, Wash., home.

Mrs. Clark said that her husband gave up smoking because of health concerns. "He said it was the hardest thing he ever had to do."

But although researchers have found that quitting often gives the body time to repair the damage of cigarette smoking, in his case apparently it came too late.

He went on to develop severe bronchitis and never really felt well, retiring at 56.

"But he could no longer keep up with his friends on the golf course and the slightest exertion left him breathless and tired," his widow said. Doctors first diagnosed emphysema, a chronic obstructive lung disease, followed by congestive heart failure and cardiomyopathy, a disease that attacks the muscle of the heart.

By the time Clark became a candidate for an artificial heart, his heart disease was terminal and he had no other options.

He decided to have the artificial heart implanted "to make a contribution" to medical science, his wife said. "I would say that the personal benefit to him was the fact that he was able to stay alive long enough to give the doctors a lot of data . . . . It proved the artificial heart is worthwhile.

I regret his suffering, but I still think he did the right thing," Mrs. Clark said. She said he "made his mind up when he went into this to see it through" and never considered asking for the artificial heart to be turned off.

If Clark had survived, he would have been tethered for the rest of his life to the machinery driving his heart by six-foot electrical cords. But Mrs. Clark said, "We didn't mind that too much, because he had been sick for some time and we hadn't been able to move about much."

In the beginning, the Clarks both had hopes that he eventually would get out of the hospital, but "the longer things went on and he experienced ups and downs, he became concerned about it."

The high point came when Clark was transferred out of intensive care to a private room with a view of the snow-capped mountains. One of the most disappointing moments came a few days later, when he was sent back because of lung problems requiring a respirator.

Mrs. Clark said that she was concerned about a lingering death, but when the time came, "God and my husband took care of that beautifully.

"I was with my husband when Dr. William DeVries said, 'He is dead. Do you want to stay while we turn the machine off?' I said, 'No.' I kissed him and went into the next room . . . . Emotionally, I was spent."