Hart, the 33-year-old scion of a Canadian wrestling dynasty, apparently became detached from a harness as he was being lowered by cable from the rafters in the Kemper Arena on to the ring for a fight that was to be broadcast live on pay-per-view television. Hart, known as the "Blue Blazer", fell 50 feet.
Well accustomed to stunts that appear to go wrong but which have been carefully scripted in advance - just as the bouts themselves are meticulously rehearsed and never for real - the 14,000 spectators inside the arena were not surewhether the fall was an accident or simply part of the show.
Fans remained confused even as medical attendants rushed in to the ring and attempted to revive the fighter. Witnesses said Hart dropped like a stone and landed first on one of the padded corner posts that hold the ropes around the ring's edge. As his head hit the post, it was snapped back. He was declared dead shortly after the accident after being taken to a nearby hospital.
The tragedy is an unexpected blow to a sport which in the past decade has seen an explosion in its popularity. The World Wrestling Federation (WWF), which had Hart as one of its stars, now produces 15 hours of live television every week for an estimated audience of 35 million.
It is a revival that has not escaped controversy. Much more than just a sport, wrestling is now a swill of pyrotechnics, soap opera, rock music and, above all, maximum bodily violence. Groins are punched, chairs are smashed and lewdness is celebrated with prostitutes, swearing, homophobia and even simulated sex.
For now though, all attention is directed at Sunday's mishap in Kansas City. "We at the WWF are saddened by the tragic accident that occurred here tonight," the WWF President, Vince McMahon, said late on Sunday. Viewers at home werespared the drama. The cameras missed Hart's fall. As emergency workers tried to save him, the cameras showed only the reaction among spectators.
Hart was the son of Stu Hart, a former wrestler and promoter from Calgary, Alberta, who sent seven sons into the business.