WASHINGTON - US VICE-PRESIDENT Dick Cheney on Wednesday underwent successful treatment for an irregular heartbeat that led him to cancel appearances at the White House and a political rally, his office said.

Mr Cheney, who had his first heart attack at 37 and his fourth in 2000, returned home after a nearly two-hour hospital stay and was expected to be back at work as scheduled on Thursday, said spokesman Megan Mitchell.

Doctors had diagnosed a recurrence of atrial fibrillation, an abnormal rhythm involving the upper chambers of the heart, and recommended he undergo treatment for the second time in under a year.

'The vice president is home and resumed his normal schedule.'

The health issue forced Mr Cheney, 67, to cancel a planned appearance at a campaign event in Illinois and instead telephone the reception to express his support, the spokesman said.

Mr Cheney also missed 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 - on the global financial meltdown.

Mr Bush, who later traveled to Michigan for a political fundraiser, told reporters hours before the procedure that 'the vice-president is doing fine,' and that Mr Cheney had told him of his condition during their morning briefings.

'He came in and told me he was going to head back into the hospital to have his, you know, his heart checked, worked on,' said Mr Bush. 'And he was confident, his doctors are confident, and therefore I'm confident.'

Mr Cheney, one of the most powerful and controversial vice-presidents in US history, underwent an angioplasty weeks after taking the oath of office in January 2001 and had a pacemaker implanted that same year.

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

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

And the vice-president went on a course of blood thinners after doctors discovered a blood clot behind his left knee following a nine-day trip to Asia in March 2007.