Defense Secretary Les Aspin underwent surgery to implant a heart pacemaker Thursday. Everything went "perfectly well" and he will be able to return to regular activity in about a week, his physicians said.

"Everything went fine," Dr. David Pearle, Aspin's cardiologist said after the 90-minute procedure. "We're very pleased with how everything went."The 54-year-old defense secretary had the device placed just under the skin near the collarbone in a procedure designed to correct a worsening heart problem.

It is also supposed to relieve him of the shortness of breath that has hospitalized him twice in the past three weeks, but the physicians said the secretary may not experience the full benefits of the surgery for several weeks.

Pearle met with reporters at the Georgetown University Medical Center, where the procedure was conducted Thursday morning.

Dr. Al Soloman, the pacemaker specialist who conducted the surgery, said Aspin was "awake and coherent" during the procedure.

"There were no complications. It went perfectly well," Soloman said. The specialist said Aspin should remain in the hospital between 24 to 48 hours, and remain in the Washington area for the next week.