Reaching what doctors called a "milestone" in his "very spectacular recovery," artificial-heart recipent William J. Schroeder walked today for the first time since his operation Sunday, steadied by the surgeon who implanted the mechanical device.

He also got that beer he has been asking for all week, gulping it down and declaring that "Coors cures."

"It brings back the old dad," said Schroeder's eldest son Mel, 30, at a news conference attended by Schroeder's wife, Margaret, and the couple's six children. Soft-spoken Margaret Schroeder said that, regardless of the outcome, her husband's experimental surgery has "already been a success."

"We have been given another few days with him, weeks, months and hopefully years," she said. "We have no regrets."

She said that before the operation, her husband's failing heart had made him so sick -- exhausted, short of breath and confined to bed -- that he would not have been alive today.

"I felt that my husband was fading away from me," she said. "Now I feel that I have him back again and I have another chance."

She described gingerly placing her hand on his chest to feel the unusual "thump, thump" of his new heart. "It's different, but at least it's beating," she said. "Before he went in there, I didn't know if it was beating or not. It was very weak."

"I don't think we're ever going to be relaxed," said the Schroeders' son Terry, 25. "We're just really glad he could still be with us, even if it's just a little time."

The close-knit family is from Jasper, a town of 10,000 in southern Indiana. They said they enjoy spending time together, going to the country, fishing, playing cards and having cookouts. But Margaret Schroeder said that if all went well with her husband, they would be happy just to take him back home to "sit and talk with us."

For now, said Mel Schroeder, "we're not thinking six months down the road, we're just looking at tomorrow."

Today, Schroeder, his family and doctors were delighting in his surprisingly swift recovery to date. That he could get out of bed at this point was an unexpected "bonus."

Schroeder, 52, walked five feet to a chair and sat there for nearly half an hour, said Dr. Allan M. Lansing, head of the Humana Heart Institute International, where the surgery took place.

Lansing said that as Dr. William C. DeVries helped Schroeder to his feet and told him to put his arms around his neck, DeVries joked: "Careful now, I'm liable to give you a big kiss." Replied Schroeder: "If you're going to kiss me, I'll walk by myself."

Although Schroeder kept his arm over DeVries' shoulder, he "carried his full weight," Lansing said. Two 8-foot-long plastic tubes connect Schroeder to a bulky, 323-pound power system for his new heart.

"Admittedly, he was really tired," Lansing said, but he noted that only Saturday, Schroeder "couldn't get out of bed at all."

The doctor also said laboratory analysis of Schroeder's natural heart provided "unexpected" findings suggesting that, in addition to diagnosed coronary artery disease, Schroeder's immune defense system had attacked his heart muscle.

Lansing said this might have hastened Schroeder's deterioration prior to surgery.

He said pathologist Stephen Johnson's analysis confirmed that "almost the entire heart" muscle had been destroyed by coronary artery disease, leaving a mass of nonfunctioning scar tissue.

Schroeder has had at least one heart attack, in January 1983.

The tests also suggested that Schroeder's heart was under attack by his body's immune system; special microscopic techniques showed evidence of so-called "immune complexes," clumps of antibodies attached to the heart muscle cells. Antibodies are a response to infection.

"We don't know the significance," said Lansing, who speculated that the reaction might have been stimulated by antibiotics Schroeder had taken.

Lansing said Schroeder's vital signs remained good. His kidney and liver functions were said to be improving, and there was no sign of infection.

Schroeder is suffering from some minor complications, Lansing said. The patient was reported to be coughing frequently to clear his lungs.