Former President Ford underwent an angioplasty procedure at the Mayo Clinic, his spokeswoman said Friday.
Stents were placed in two of his coronary arteries to increase blood flow during the procedure performed Thursday, according to the statement from Penny Circle, Ford's spokeswoman.
She said Ford, 93, was resting comfortably in his hospital room.
Mayo Clinic spokesman John Murphy confirmed the procedure, but would not comment further on Ford's condition.
"No further releases or updates are anticipated for several days," he said.
Ford was admitted to the clinic Aug. 15 for tests and evaluation. He was fitted with an implantable cardiac pacemaker on Monday.
Ford spent a few days in Colorado's Vail Valley Medical Center in July because of shortness of breath. In January, he was hospitalized for 12 days in Rancho Mirage, Calif., to treat pneumonia. Five years ago, Ford suffered two small strokes and spent about a week in a hospital.
Ford became the nation's oldest living former president after the death of Ronald Reagan in 2004.
Ford was House minority leader when President Nixon chose him to replace Spiro Agnew, who resigned, as vice president in 1973.
Ford became president on Aug. 9, 1974, when Nixon resigned amid the Watergate scandal.
Ford and his wife live in Rancho Mirage.