Doctors administered an electrical shock to Vice President Dick Cheney's heart and restored it to a normal rhythm during a 2 1/2 -hour hospital visit yesterday.

Cheney, who has a history of heart problems, was discovered to have an irregular heartbeat about 7 a.m. when he was seen by doctors at the White House for a lingering cough from a cold. He remained at work throughout the day, joining President Bush in meetings with Mideast leaders.

The irregular heartbeat was determined to be atrial fibrillation, an abnormal rhythm involving the upper chambers of the heart, said spokeswoman Megan Mitchell. He went to the hospital about 5 p.m. and was discharged about 7:30 p.m.

"He'll probably have other episodes," said Eldadah, who is not involved in Cheney's care. "Atrial fibrillation in and of itself is not threatening. The problem is that it has long term consequences. It increases the risk of stroke." He said Cheney probably would be put on the most potent blood thinner.