BEDFORD, N.Y. – Christopher Reeve, the star of the “Superman” movies whose near-fatal riding accident nine years ago turned him into a worldwide advocate for spinal cord research, died Sunday of heart failure, his publicist said. He was 52.

Reeve fell into a coma Saturday after going into cardiac arrest while at his New York home, his publicist, Wesley Combs said from Washington, D.C., on Sunday night.

Reeve was being treated at Northern Westchester Hospital for a pressure wound, a common complication for people living with paralysis. In the past week, the wound had become severely infected, resulting in a serious systemic infection.

“On behalf of my entire family, I want to thank Northern Westchester Hospital for the excellent care they provided to my husband,” Dana Reeve, Reeve’s wife, said in a statement. “I also want to thank his personal staff of nurses and aides, as well as the millions of fans from around the world who have supported and loved my husband over the years.”

Reeve broke his neck in May 1995 when he was thrown from his horse during an equestrian competition in Culpeper, Va.

Enduring months of therapy to allow him to breathe for longer and longer periods without a respirator, Reeve emerged to lobby Congress for better insurance protection against catastrophic injury and to move an Academy Award audience to tears with a call for more films about social issues.

He returned to directing, and even returned to acting in a 1998 production of “Rear Window,” a modern update of the Hitchcock thriller about a man in a wheelchair who becomes convinced a neighbor has been murdered. Reeve won a Screen Actors Guild award for best actor in a television movie or miniseries.

“I was worried that only acting with my voice and my face, I might not be able to communicate effectively enough to tell the story,” Reeve said. “But I was surprised to find that if I really concentrated, and just let the thoughts happen, that they would read on my face. With so many close-ups, I knew that my every thought would count.”

In 2000, Reeve was able to move his index finger, and a specialized workout regimen made his legs and arms stronger. He also regained sensation in other parts of his body.

Reeve’s support of stem cell research helped it emerge as a major campaign issue between President Bush and Sen. John Kerry. His name was even mentioned by Kerry earlier this month during the second presidential debate.

As for the strain of traveling to Hollywood, Reeve said: “I refuse to allow a disability to determine how I live my life. I don’t mean to be reckless, but setting a goal that seems a bit daunting actually is very helpful toward recovery.”

His athletic, 6-foot-4-inch frame and love of adventure made him a natural, if largely unknown, choice for the title role in the first “Superman” movie in 1978. He insisted on performing his own stunts.

Although he reprised the role three times, Reeve often worried about being typecast as an action hero.

“Look, I’ve flown, I’ve become evil, loved, stopped and turned the world backward, I’ve faced my peers, I’ve befriended children and small animals and I’ve rescued cats from trees,” Reeve told the Los Angeles Times in 1983, just before the release of the third “Superman” movie. “What else is there left for Superman to do that hasn’t been done?”

Though he owed his fame to it, Reeve made a concerted effort to, as he often put it, “escape the cape.” He played an embittered, crippled Vietnam veteran in the 1980 Broadway play “Fifth of July,” a lovestruck time-traveler in the 1980 movie “Somewhere in Time,” and an aspiring playwright in the 1982 suspense thriller “Deathtrap.”

“After the first ‘Superman,’ I had the compulsion to do parts that were really weird,” Reeve said in 1987. “That freaked people out. I’ve passed that.”

More recent films included John Carpenter’s “Village of the Damned,” and the HBO movies “Above Suspicion” and “In the Gloaming,” which he directed. Among his other film credits are “The Remains of the Day,” “The Aviator,” and “Morning Glory.”