Two months after William J. Schroeder received an artificial heart, his doctor says Schroeder is ready to make history again by taking his first trip outside Humana Hospital-Audubon.

The only obstacle between Schroeder and a ride around town in a van is Louisville's frigid weather, said Dr. William DeVries in an interview.

Schroeder is physically stronger than he was before his Dec. 13 stroke, walking the equivalent of four city blocks a day and riding an exercise bike. But his mental state is more difficult to assess because he has difficulty communicating, DeVries said.

Schroeder often tries to answer questions by nodding but then saying "No," DeVries said. When pressed to explain what he means, Schroeder will pause, struggle for the right word and correct himself.

At times, the patient will volunteer full sentences, DeVries said. "On Christmas Day, for example, he told me very clearly, just like I'm talking to you: 'Thank you for giving me this day.' He said that to me just as clear as a bell."

But particularly toward late afternoon, "He'll say, 'I want something,' and he'll start mumbling and you don't know what it is." At those times, DeVries said, "We have to continue to bring it out of him. And that's going along much better, a lot faster than it has, but it takes time."

Schroeder still suffers from short-term memory loss. "If you'd gone in Sunday and said, 'Who won the Super Bowl?' right after the Super Bowl, he might not remember -- but the next day he might," DeVries said. On the other hand, Schroeder can quote communion prayers flawlessly, and knows the names of all his grandchildren.

Schroeder is no longer clinically depressed, DeVries said, and is still taking antidepressant medication. "He's made no effort or no communication in any way saying he wants to die, or he wants to have the machine turned off, or anything like that," DeVries said.

Schroeder's psychological health is of particular concern as the medical team begins the process of weaning Schroeder and his wife, Margaret, from the security of the hospital. Schroeder received his heart implant Nov. 25.

In several weeks, the Schroeders are expected to move from the hospital to a two-bedroom apartment across the street that Humana purchased in December to serve as a halfway house for transplant and artificial-heart recipients. The apartment is being renovated to include ramps and compressed-air outlets to power the Utahdrive pump used with the mechanical heart.

"It's a process that has to be gradual, because if there is a step that comes up that's too big, then there is too much anxiety," said Schroeder's psychiatrist, Dr. Lawrence Mudd.

Everyone involved, including the Schroeders, is traveling uncharted ground. The only other recipient of a permanent artificial heart, Seattle dentist Barney B. Clark, died in the Utah hospital where the mechanical device kept him alive for 112 days.

For the past few weeks, the Humana hospital team has been meeting daily to develop a plan to increase the Schroeders' confidence in the machinery and their sense of security outside the hospital.

The entire Schroeder family is taking lessons in operating the Utahdrive pump and its backup systems, learning what to do in the event of a power or pump failure.

"When they leave the hospital, it will be the first time they've been alone with the machine . . . but you can only worry for so long," said Dr. Allan M. Lansing, medical director of Humana Heart Institute International.

Meanwhile, a van is being adapted for Schroeder's use. The 1985 vehicle is being converted to a type of mobile hospital room with a siren, emergency lights, an electric power source and a mobile telephone. The van may be completed by Valentine's Day, Feb. 14, when Schroeder turns 53.

DeVries said that Schroeder has shown interest in the van, saying, "I'd like a ride."

Meanwhile, the Humana medical team says it expects to find a candidate by late February for the third artificial heart implant.

More than a dozen candidates have been screened but none has met enough of the criteria to be presented to the hospital's special review committee, DeVries said.

Although it has been estimated that thousands of lives could be saved with artificial hearts, DeVries said that the inquiries to the institute are coming in slowly. "They're waiting to see what happens to Bill Schroeder," DeVries said.