Reggie Lewis, the Boston Celtics’  leading scorer who fainted during an NBA playoff game three months ago, died Tuesday night in Waltham, Mass., after collapsing while shooting baskets at Brandeis University.

Lewis was in cardiac arrest when paramedics arrived at the gym, and was pronounced dead at 7:30 p.m. EDT at Waltham-Weston Hospital, where emergency room physicians tried to revive him. He was 27.

Lewis leaves a wife, Donna Harris-Lewis, who is pregnant, and a son, Reggie Jr., who will turn 1 next month.

“We’ve lost a very treasured member of our family today,” said Dave Gavitt, Celtic senior executive vice president. “It’s a time of incredible grief.”

Gavitt called Lewis “a gentle, kind, wonderful, considerate guy who just had so much to give to the city of Boston.”

Cause of death was not immediately announced, and Dr. Mary Anne McGinn of Waltham-Weston declined to answer questions, at the family’s request.

Lewis’ medical condition had been controversial since his collapse April 29 during a game against the Charlotte Hornets. His condition was first diagnosed as a life-threatening heart disorder and the Celtics announced his career probably was over.

But Lewis sought another opinion, and his condition was diagnosed as a benign nerve disorder that caused fainting spells. In an interview last May with Jimmy Myers of Celtic-owned WEEI radio, Lewis said he would consider a third opinion.

“You’re never 100% sure about anything–especially lately,” Lewis said. “We’re still discussing things, and we’re going to make the decision we are sure is right for me.

“I know this thing is never going to go away until I step on the basketball floor. And even then, everyone is going to be watching to see if I collapse again.”

Amir Weiss, who was at the Brandeis gym, told reporters Lewis was not overexerting himself at the time of incident.

“When I looked over, Reggie was on the floor,” he said. “We went over to look at him and he was gasping for air.”

He said Lewis was limp and shaking and, after a few minutes, “he stopped breathing.”

Deo Djossou, a senior on Northeastern’s basketball team, said he spoke with Lewis on Sunday about plans to start working out with about 12 local college players. Lewis attended Northeastern.

Djossou said they were to begin practicing Monday, but the session was rescheduled until 6 p.m. Tuesday because many players did not have transportation.

Lewis, a first-round 1987 draft pick and Boston’s top scorer the past two seasons, had not participated in team practices since the April 29 collapse.

Lewis did not participate in the Celtic rookie/free-agent camp July 11-14, although he attended some of the sessions. He also was not involved with the Celtics’ team in a summer league that ended Sunday in New York.

Lewis averaged 20.8 points in each of the past two seasons, and was considered to be the Celtics’ next star after the retirement of Larry Bird.

Coach Jim Calhoun of Connecticut, a close friend of Lewis’, was too upset to comment on the death. Calhoun coached Lewis for three seasons after recruiting him out of Baltimore’s Dunbar High.

Lewis was once overshadowed on a legendary Duncluded future NBA players Tyrone Bogues, David Wingate and Reggie Williams “I think all of us who work in basketball anso seriously should understand that even though our jobs are important, maybe tportant as we think,” Jerry West, Laker general manager, said in a statement.

“These are all things that make us wonder about this game at times.”

Said David Cowens, a former Celtic star who was at the hospital Tuesday night: “He was a great athlete. He was one of the guys who bucked the odds and became a professional athlete.”

Although coming out of Northeastern, Lewis, a 6-foot-7 swingman, became one of the NBA’s best scorers.

Lewis averaged 4.5 points in 49 games as a rookie. But he blossomed in 1988-89, averaging 18.5 points.

Although Lewis was emerging last season, he was experiencing lightheadedness early in the year. He almost fainted in a March 24 game against the Miami Heat.

“You have to think, was he examined after that game?” asked Donna Harris-Lewis in an interview last May. “No. Then if there had been some episodes prior to that, you have to wonder why didn’t someone thoroughly examine it.”

But once Lewis underwent a battery of examinations at New England Baptist Hospital in Boston after the April 29 incident, his condition was diagnosed as a heart disorder known as focal cardiomyopathy.

Mark Estes, an electrophysiologist involved in the diagnosis, said the apex of Lewis’ left ventricle appeared to have scar tissue. Such a condition could trigger an exercise-induced arrhythmia, or fast heartbeat. Sources familiar with Tuesday’s episode said Lewis was experiencing an irregular heartbeat known as ventricular fibrillation at the hospital.

The controversy surrounding Lewis’ condition started when he decided to get a second opinion at Brigham and Women’s Hospital, also in Boston. Gilbert Mudge, director of clinical cardiology there, said Lewis was suffering from neurocardiogenic syncope, a fainting condition that some physicians said would not prevent him from continuing his basketball career.

Mudge was unavailable for comment Tuesday night.

“There has been considerable amount of concern in the medical community for the potential for a serious life-threatening arrhythmia and that our worse fears have been actualized here,” Estes said Tuesday. (But) how a physician chooses to interpret and weigh each one of those tests is not an exact science by any means.”

The case has similarities to that of Hank Gathers, who collapsed during a Loyola Marymount game in March of 1990 and died about 90 minutes later. Gathers had been taking medication to control a rapid heartbeat at the time of his collapse.

“It’s almost the same story all over again,” said David Cannom, a cardiologist at the Good Samaritan Hospital of Los Angeles. “I think it is going to cause enormous shock waves through the sports community and, in turn, the people who take care of athletes.”