Johnathan Edward Szeles, who gained mainstream fame and was a year-round headliner in Las Vegas for his standup comedy and magic shows, has died from a terminal heart condition, according to reports. He was 63. Szeles, better known by his stage name “The Amazing Johnathan” died in his sleep around 11:30 p.m. on Tuesday at his home in Las Vegas, fellow standup comic Penny Wiggins said on Facebook. “A very very sad day. … Johnathan Szeles (Amazing Johnathan) has passed away,” she wrote. “My heart is broken … one of my best friends, one of the funniest humans I’ve ever met … I loved him so very much and will never forget this wonderful, amazing, kind, funny, great person.” Szeles started his early career by performing acts in the streets of San Francisco and made his first television appearance in 1983 on “The 8th Annual Young Comedians Show.” The self-described “Freddy …