LOS ANGELES (Reuters) - Ailing rock 'n' roll pioneer Bo Diddley suffered a heart attack while undergoing a medical check-up, and is in stable condition in a Florida hospital, his spokeswoman said on Tuesday.

The 78-year-old musician, whose distinctive rhythms and guitar style influenced rockers from Buddy Holly to the Rolling Stones and U2, felt unwell during a check-up last Friday at North Florida Regional Medical Center in Gainesville, Fla. He was transferred to the emergency room where he suffered the heart attack, spokeswoman Susan Clary said in a statement.

He underwent surgery so that a stent could be fitted to help blood flow to his heart. He was moved from intensive care to cardiac care on Tuesday morning, Clary said.

Diddley, whose real name is Ellas Bates, suffered a stroke in May. It left no physical disability, but it impaired his speech and speech recognition, his manager said at the time. In recent years he also lost some toes to diabetes.

Diddley helped lay the foundation for rock 'n' roll in the mid-1950s when he developed a syncopated "hambone" beat -- known as the "Bo Diddley" beat -- that was aped by Holly on "Not Fade Away," the Who on "Magic Bus," George Michael on "Faith" and U2 on "Desire."

He topped the charts in 1955 with the song "Bo Diddley" and went on to enjoy such hits as "Mona" (covered by the Rolling Stones), "Who Do You Love," and "I'm A Man."

He also cut an imposing figure on stage, sporting a pair of thick spectacles and playing a rectangular guitar. He was inducted into the Rock and Roll Hall of Fame in 1987, alongside bluesman Muddy Waters, and soul icons Aretha Franklin and Marvin Gaye. But he never received the same sort of mainstream recognition as his peers, and frequently complained that he never received a royalty check.