A year ago, Bill Schroeder could feel his life slipping away as he fought for every breath. Sitting up for someone to brush his teeth exhausted him. His diseased heart could pump only a few more days.

But the 52-year-old father of six from Jasper, Ind., wanted to reach some milestones: spending one more Christmas with the family, attending his son's spring wedding and the christening of a grandbaby on the way.

After Dr. William C. DeVries replaced his failing heart with a mechanical pump last Nov. 25 at Humana Hospital-Audubon, Schroeder did live through those events -- surviving longer, in fact, than any other recipient, human or animal, of a Jarvik-7 heart.

But his bargain for time was costly. He has suffered a host of complications, including three strokes that have permanently damaged his short-term memory and speech.

Now his family doesn't know whether he remembers those cherished occasions. Although he was the first artificial-heart patient to live outside a hospital in an apartment, he was readmitted Nov. 11 after his third stroke left him weak and mute, at times only dimly aware of his surroundings, according to DeVries.

"Sometimes I wonder myself what keeps him going," Schroeder's son Mel, 32, said last week. "The only thing that I can think of is that somewhere in the back of his mind he's hoping he'll be able to go home some day and just be with his family. That's really the only thing that's left."

After Schroeder's operation, DeVries implanted permanent devices in two more patients. Murray P. Haydon has endured bleeding, a transient stroke, breathing difficulties, pneumonia and infections during nearly nine months in intensive care. Jack Burcham died of internal bleeding in April after 10 days with a Jarvik-7.

A Swedish recipient of the Jarvik-7, Leif Stenberg, died Thursday in Stockholm of respiratory and vascular failure after 229 days with the artificial heart.

Two men sustained temporarily on Jarvik-7s, Michael Drummond in Tucson and Thomas Gaidosh in Pittsburgh, later received human heart transplants. Both were allowed to go home this month.

Last November, Schroeder was hoping that a permanent implant would enable him to do the same.

Schroeder's wife, Margaret, remembers that "in the beginning, we kind of thought Bill would be better and we'd take him home to Jasper. He'd get better and that'd be it." Her husband of 33 years had been so close to death that the risks outlined in the consent form "really didn't make any difference . . . . They could have read that thing to me from top to bottom and backwards and every other way -- all I would have cared about was, 'Is it going to help Bill or not?' "

For a spectacular 18 days, it seemed that experimental technology had pushed Schroeder's dream to within his grasp.

"It was like the difference between night and day. We had the 'old Dad' back again," Mel Schroeder said. His father wisecracked his way through his initial recovery, asking his doctor for a beer and upstaging President Reagan's congratulatory telephone call with complaints about "getting a runaround" over Social Security benefits.

Schroeder became so boisterous telling salty jokes and inviting visitors to feel his heart, "just pumping like an old-time thrashin' machine," that nurses sometimes had to tap on the sliding-glass door, warning him not to keep other intensive-care patients awake.

On national television, the only man alive without a human heart wept with thanks for his life. He planned to get a customized van to take fishing and to ball games, to have picnics "and in the fall, hunt walnuts."

But on Dec. 13, hours after his government benefit check had been hand-delivered to him, blood clots from the device lodged in Schroeder's brain, and the dreams came crashing down. The celebrated patient began a rocky, subdued struggle, dogged by fever, weakness, anemia, seizures and two more strokes.

In January, Schroeder regained enough strength to walk the equivalent of three blocks, but was felled by a mysterious, lingering fever that sapped his strength and spirit. Cameras filmed a man in a wheelchair who made slow-motion gestures and sometimes seemed to stare blankly. He often said "yes" when he meant "no," and other thoughts snagged somehwere inside him. He was treated with antidepressants.

His sons took him for brief outings in a van -- to a park, to a farm to fish, to a family seafood restaurant for his wedding anniversary and later to a baseball game. In March, when he was too weak to travel to Jasper for his son's wedding, the family held a "mock" wedding at the hospital here. Schroeder wore a tuxedo, sampled champagne, clapped to the music and stood from his wheelchair for a few seconds, trying to dance.

In April, Schroeder and his wife moved into an apartment across the street from Humana Hospital-Audubon. The building, bought and renovated by the hospital company, has alarms hooked up to the hospital and an apartment for nurses assisting with Schroeder's care. Within a month, a second stroke left him lethargic and unable to speak for weeks.

By August, having confounded doctors' grim predictions, he moved back to the apartment. That month, he was also driven the 90 miles for a two-hour visit to his Jasper home, accompanied by press, public relations aides, technicians and family. He rode in the town parade.

In September, he rode in a horse-drawn surrey around Churchill Downs racetrack with relatives of DeVries' other artificial-heart patients, and led the hospital's annual walk-a-thon for former heart patients.

During the months in the apartment, the Schroeders scaled down their dreams. "The little things that he does with me and to the family that remind me of home, I guess that would mean more than anything," Margaret Schroeder said.

On good days, the two would breakfast, then watch "The Young and the Restless." Or, if the weather was good, they would haul the artificial heart's heavy power source onto the back porch and watch birds.

Schroeder would have physical therapy at the hospital, then return for a nap. He learned to feed himself and brush his teeth. Sometimes, Margaret Schroeder would try to include her husband in such chores as doing dishes.

"He'd sit there and she'd give him a dish and he'd dry it and put it up. I think that really made him feel good that he could do something," Mel Schroeder said.

In the evening, the couple would sit together, "maybe not carrying on a conversation like you and I do, but I learned to understand what he's talking about," Margaret Schroeder said. "Or we might play a game of cards, just little things to occupy your time. Or we'd go through a picture album and say who everybody is, or through the scrapbook. He enjoys that."

But there are so many bad days that Margaret Schroeder compares their life to a roller coaster: "It's like a stone gets in the way and we have to move that. It's like he's up on top one day and maybe down on the bottom that night or the next day. You can notice the difference. He's not talkative and he just kind of sits there and moves when he has to or when he's told to."

Several weeks ago, Margaret Schroeder collapsed from exhaustion and hypertension and was briefly hospitalized before reluctantly returning to Jasper to rest. Schroeder had to be reminded what happened and why his wife couldn't be with him. He became so frustrated that occasionally he was given sedatives, his neurologist said.

Margaret Schroeder returned to her husband's side after his third stroke earlier this month. He remains hospitalized, while she stays in the nearby apartment.

As for ending the experiment, Mel Schroeder said: "We've talked about it only to the point that we are not ready to talk about it . . . . We have never felt at any point that we wanted to even remotely think about it."

Even though his father may be "expressionless or emotionless by himself in the hospital, Mel Schroeder said, if he sees a family member "he'll be wide awake. He becomes emotional for you and it just tells me he really wants to be around you."

DeVries told reporters this week that when Schroeder faced certain death a year ago, "he took the choice that he wanted to be involved in this. He thought he would be lucky. It's a lot better than the alternative -- we lose track that he would have been dead that weekend."