U.S. House candidate Larry Diedrich (search) had heart surgery Wednesday to replace an aortic valve that was leaking, and his doctor said he came through it well.

The 46-year-old Republican will have to stay in the Heart Hospital of South Dakota (search) from four to seven days while medical personnel monitor his recovery, said Dr. James Reynolds of Sioux Falls.

"The surgery went as planned," Reynolds said. "There were no surprises or finding other than what we had anticipated."

The procedure involved splitting Diedrich's sternum with a 12- to 14-inch incision and replacing the heart valve with a mechanical valve. Diedrich's age and good health were advantages in the surgery, Reynolds said.

Diedrich, an Elkton farmer and former state lawmaker, lost to Democrat Stephanie Herseth (search) in a June 1 special election to fill out the term of former Rep. Bill Janklow (search), who resigned in January. They will face each other again in the November election for a full two-year term.

Diedrich had said he wanted to start making campaign calls in a couple of weeks, but Reynolds said Wednesday that resuming a "full-speed-ahead campaign" in two weeks would be "pushing it."