As conservative radio talk-show host Rush Limbaugh underwent tests for chest pains in a Honolulu hospital, caller after caller to his show sounded their well-wishes.

Fans were asked to simply say "ditto" — a traditional Limbaugh catchword — to express their support Thursday so they could get on with questions and comments on social and government issues on the national talk show.

Limbaugh experienced chest pains Wednesday and was rushed from the Hawaii resort where he's vacationing to The Queen's Medical Center. A statement Thursday from the hospital said he was resting comfortably in "good spirits."

George Mason University economics professor Walter E. Williams, vacation relief for Limbaugh on the three-hour show, said the chest pains could be an indicator of a cardiac event, although the cause hasn't been determined.

"Obviously, out of respect for Rush's medical privacy ... we'll wait for him to provide detailed comment as to the cause," he said.

Kit Carson, Limbaugh's chief of staff, said Limbaugh left for his Christmas vacation Dec. 23 and was due to return to his show Jan. 4. Carson didn't have any information on whether that schedule would change.

"We found out what happened and today they're looking at him — testing him, kicking the tires — and we don't have any conclusion from that yet," Carson said late Thursday.

TV satellite trucks were parked across the street from the hospital as news of Limbaugh's health problems vied for media attention with President Barack Obama and his family, who is spending the Christmas and New Year's holidays across the island in a private home.

"Ditto!" echoed newlywed Jeff Steele of Lexington, S.C., when asked if he was a Limbaugh fan.

The Steeles said they weren't aware Limbaugh was even in Honolulu until a relative called to say he'd been staying at their hotel.

"We're a little detached from the world," Steele said. "But we are conservatives."

Americans in a poll last month called him America's most influential conservative voice, and more than 14 million people hear him at least once a week, making him the nation's highest-rated broadcaster.

His medical problems have attracted attention in the past. In 2003, he acknowledged an addition to pain killers for severe back pain and took a five-week leave from his radio show to enter rehab.

In 2001, Limbaugh said he had been diagnosed with autoimmune inner-ear disease and had surgery to have an electronic device placed in his skull to restore his hearing.

Leah Phui, desk manager at The Kahala Hotel and Resort, declined to confirm or say anything about Limbaugh's stay. She said a photo of Limbaugh with girlfriend Kathryn Rogers on the hotel's celebrity wall — flanked by shots of record producer Dr. Dre and singer Alicia Keyes — was taken during a February visit.

The Kahala, in a quiet residential neighborhood, is popular with celebrities seeking isolation from Oahu's crowded beaches. It features a lagoon with performing dolphins and a secluded beach and it boasts that every president since Lyndon Johnson has either stayed there or attended an event at the resort near the landmark Diamond Head crater.