US Vice President Dick Cheney has had treatment for a irregular heart beat.
Dick Cheney has a long history of heart trouble
Doctors at George Washington University Hospital gave him an electrical shock to restore the heart's normal rhythm.
Mr Cheney, who has a history of heart conditions, spent two and a half hours there after seeking treatment for "a lingering cough from a cold".
Mr Cheney, 66, has had four heart attacks, quadruple bypass surgery and operations to clear blocked arteries. He was fitted with a pacemaker in 2001.
In July, the vice president had minor surgery to replace the pacemaker's battery which was running low.
Mr Cheney has also had operations to clear blood clots in his knees and in March started taking blood-thinning medicine to treat another blood clot in his lower left leg.
"During examination he was incidentally found to have an irregular heartbeat," said hospital spokeswoman Megan Mitchell.
She said that the condition was determined to be atrial fibrillation, an abnormal rhythm involving the upper chambers of the heart.
Mr Cheney then received cardioversion - a procedure that involves the delivery of an electric impulse to the heart.
Mr Cheney left the hospital and returned home early on Monday evening.
"The vice president... will resume his normal schedule tomorrow at the White House," said the hospital spokeswoman.
About 2.8 million Americans suffer from atrial fibrillation, the most common type of heartbeat irregularity.