America's vice president Dick Cheney has had minor surgery to replace the batteries on his heart device on Sunday, US media reported.
The 66-year-old Cheney was treated at George Washington University Hospital but he did not stay overnight.
He arrived with his wife Lynne in the morning and left at noon.
Mr Cheney has a history of heart problems. He has suffered four heart attacks, had quadruple bypass surgery, two artery-clearing angioplasties and an operation to implant the defibrillator in June 2001.
The defibrillator monitors Cheney's heart and delivers a shock if it ever goes out of rhythm.