US Vice President Dick Cheney cancelled a planned political event and will see his doctors Wednesday after experiencing a recurrence of an abnormal heart rhythm, his spokeswoman said in a statement.

"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," said Megan Mitchell.

"Later this afternoon, the vice president will visit George Washington University Hospital for an outpatient procedure to restore his normal rhythm," said Mitchell. It will be the second such procedure in less than a year.

The health issue forced Cheney, 67, to cancel a planned appearance at a campaign event in Illinois.

Earlier, the vice president was absent from a meeting of US President George W. Bush's cabinet -- the name card usually by his seat as well as a glass of water could be seen on a small side table.

Aboard Air Force One, Bush spokesman Tony Fratto told reporters Cheney had attended routine morning security meetings with Bush, and informed him of his condition. Bush wished him well, the spokesman added.

Cheney had his fourth heart attack in 2000, the year he and Bush won the White House. Cheney underwent an angioplasty weeks after being sworn in as vice president in 2001 and had a pacemaker implanted that same year.

In September 2005 Cheney had an operation for blood clots behind each of his knees, and in January 2006 he was hospitalized for shortness of breath.

In November 2007, Cheney underwent treatment for the same irregular heartbeat, which required an electrical impulse to restore the upper chambers of the heart to normal rhythm.