The 58-year-old actress was set to undergo bypass surgery at the Kootenai Medical Center in Couer d'alene, Idaho, the same medical facility where last spring Pearce received a stint in her heart to improve blood flow, "Entertainment Tonight" reported.
The actress, a child star known for the 1960s sitcom "The Patty Duke Show," won an Oscar in 1963 for playing Helen Keller in "The Miracle Worker." She has won several Emmys, including one in 1980 for playing Keller's teacher in a TV movie.
She is scheduled to appear at Kootenai Medical Center later this month for the annual Christmas tree benefit auction, at which time the actress is expected to be fully recovered, Pearce's publicist said.
Pearce's sons, MacKenzie and Sean Astin, also are actors, with Sean playing the role of Sam the hobbit in "The Lord of the Rings" trilogy.