Two ex-chiefs, two operations. Spokespeople for former Presidents Jimmy Carter, 76, and George Bush, also 76, announced (separately) yesterday that both men require medical attention.

Bush is scheduled to undergo hip replacement surgery at the Mayo Clinic in Rochester, Minn., today. (His wife, Barbara Bush, had the same surgery there about three years ago.) No details have been given. Carter, meanwhile, fell and injured his right shoulder while jogging during a business trip to San Diego last week and underwent surgery at Atlanta's Emory University Hospital. After a few weeks of physical therapy, he is expected recover fully.