WASHINGTON - Vice President Dick Cheney on Wednesday left a D.C. hospital after an outpatient procedure to restore his normal heart rhythm following a recurrence of atrial fibrillation, the White House said.

A spokeswoman said the procedure — an electric shock administered at the hospital — went smoothly and without complication. Cheney spent the morning at the White House before the procedure. He was now home and ready to resume his normal schedule.

"During a visit with his doctors this morning, it was discovered that the vice president is experiencing a recurrence of atrial fibrillation, an abnormal rhythm involving the upper chambers of the heart," his office said in a statement.

"The vice president will visit George Washington University Hospital for an outpatient procedure to restore his normal rhythm," it added.

Cheney told President Bush of his condition. The president responded "like he would with any friend," said spokesman Tony Fratto, by wishing the vice president well and telling him to "go and make sure the doctors do what they need to do."

Later, in Ada, Mich., Bush told reporters he is confident Cheney is "going to be fine."

Same procedure in November
Cheney last November received the same procedure, which involves an electrical shock to his heart.

Dr. Zayd Eldadah, director of cardiac arrhythmia research at Washington Hospital Center in Washington, said it's not unusual for Cheney to have another such episode. An estimated 2.8 million Americans have atrial fibrillation, the most common type of irregular heartbeat and one that is not life-threatening in itself.

"This kind of rhythm problem generally does keep coming back over time," said Eldadah, who is not involved in Cheney's care. "The natural history of atrial fibrillation in people who have heart disease and are older is that it keeps coming back, and generally comes back more frequently."

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The main risk from atrial fibrillation is not that Cheney will have another heart attack, but that he could eventually have a stroke if the rhythm problem is not treated.

Atrial fibrillation, also called A-fib, causes the upper chambers of the heart to quiver, instead of pump. As a result, some blood can pool in the heart. When blood settles, it tends to clot. And if those clots are then pumped out to the body, they can lodge in tiny blood vessels in the brain, causing a stroke.

The procedure Cheney was expected to undergo Wednesday afternoon is like resetting a computer, Eldadah explained. The vice president will be sedated, and an electrical charge will be delivered to his heart. "The heart will be turned off and on to reset it," said Eldadah. "It's a quick fix to restore normal rhythm."

If the procedure doesn't work, patients typically are put on blood thinners to prevent clotting.

"Atrial fibrillation in patients like Vice President Cheney is not a source of great worry or alarm," said Eldadah. "It's very treatable."

67 and 4 heart attacks
Cheney has had four heart attacks, starting when he was 37 years old, and many related doctor and hospital visits over the years since. He has had quadruple bypass surgery and two artery-clearing angioplasties. In 2001, he had a special pacemaker implanted in his chest. The pacemaker's battery was replaced last year, and then the entire device was replaced.

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In 2005, he had surgery to repair an arterial aneurysm on the back of each knee.

In his checkup in July, doctors said Cheney's heart was beating normally for a man of his age and health history.

Cheney called off a campaign event due to the procedure. He canceled an event for Marty Ozinga, a wealthy suburban concrete company owner. Ozinga is running for the House against Democrat Debbie Halvorson, a high-ranking Illinois state senator.

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