Helms to undergo heart surgery Thursday

WASHINGTON (CNN) -- U.S. Sen. Jesse Helms of North Carolina will undergo surgery Thursday to replace a faulty heart valve installed a decade ago, his chief of staff Jimmy Broughton said Wednesday.

Helms, 80, was admitted Monday to Bethesda Naval Medical Center in Maryland for evaluation after complaining of fatigue. Tests confirmed the prosthetic mitral valve installed in 1992 during quadruple coronary artery bypass surgery had failed, Broughton said.

Thursday's surgery will be performed at Inova Fairfax Hospital in suburban Virginia, Broughton said in a statement.

"Sen. Helms, his family and his staff are deeply grateful for the expressions of support and concern he has received from countless friends across North Carolina and the nation," Broughton said.

An icon of the conservative right, Helms is serving his fifth term in the U.S. Senate where he is the ranking Republican on the Foreign Relations Committee. He had already announced he would not seek re-election this year to a sixth term.

Sen. Bill Frist, R-Tennessee, who was a heart transplant surgeon before coming to Congress, spoke to Helms' staff Wednesday afternoon to explain his medical condition.

A Helms aide told CNN Frist was "very reassuring" in telling the staff that if the senator underwent surgery, it would be "routine" and that there would be nothing to worry about.