LOS ANGELES (AP) -- Although fans recalled him as seemingly invincible, Wilt Chamberlain's sister said he had heart problems he was taking medication for and had recently lost some 50 pounds after painful dental surgery.
The NBA Hall of Fame center, arguably the most dominating player in the history of the game, died Tuesday at age 63.
Sy Goldberg, his agent and longtime friend, said Chamberlain was seeing a heart specialist just before his death.
"He did have some problems and we think at this point it may have been a heart attack that did him in," Goldberg said of the 7-foot-1 center who weighed 275 pounds in his playing days.
Chamberlain's health, including possible heart problems, were an issue off and on since the 1960s, when his former coach with the then-San Francisco Warriors was quoted as saying he might have had a heart attack before the 1964 season. Chamberlain denied it.
Nearly 30 years later, in 1992, he was hospitalized for three days after complaining of a "slightly" irregular heartbeat. Doctors said it was difficult to keep him in the hospital after the problem stabilized.
His course of treatment was not made public.
Like most players, Chamberlain had several injuries during his 14 NBA seasons, including a torn tendon in his right knee in 1969. Three years later, he led the Los Angeles Lakers to their first NBA championship despite a chipped bone in his right wrist.
Recently, he had begun to develop other health problems, some related to his basketball career, and his sister, Barbara Lewis, said Tuesday that he didn't look well when she visited with him last weekend.
He had undergone dental surgery to remove teeth knocked aside during his basketball career. That had made it difficult to eat, she said, and he had lost about 50 pounds in the last month.
"He said it was the worst pain. I never heard him complain about pain ever," she said. "He said he felt worse than he ever did Saturday. He looked worse than I have ever seen him."
It's too early to determine what caused the former basketball star's death, but heart problems compounded by stress can be fatal, said Jaime Moriguchi, co-director of the clinical heart failure program at UCLA.
If that is the case, it is possible Chamberlain suffered from ventricular arrhythmia, an irregular beat in the heart's lower chamber, the body's main blood pump.
"It causes very chaotic electrical activity. The heart cannot pump effectively at all," Moriguchi said. "At that point, you pass out and you die unless something is quickly done about it."
Without medical attention, patients die within six minutes.
Viruses and long-standing hypertension also can damage the heart and cause irregular beating, Moriguchi said.
About 350,000 sudden cardiac deaths occur in the United States every year. The condition can be treated with drugs, electrical shock and even the burning of part of the heart tissue.