Blair also used the interview to confirm that he intends to seek a third term as prime minister, but would retire from politics after completing that term.

"It is my intention to lead the Labour Party into the next election." Blair said.

"If elected, and that's the decision of the British people, then I would serve a full term. I do not intend, however, to put myself forward for elections after that."

Asked if his doctor was concerned the heart problem could be a sign of more problems, Blair said, "He assures me that it isn't."

"I think they call it an atrial flutter that I had last year recurred again in August," Blair said.

Blair said his condition "was not debilitating at all."

"I feel fine. You just get a flutter every so often," he said.

Last year, doctors diagnosed his condition as supraventricular tachycardia -- irregular heartbeat -- that caused shortness of breath. He was given an electrical treatment to stabilize his heartbeat and was sent home a few hours later with orders to rest.

Blair, 51, became prime minister in May 1997 when he led his Labour Party to its first electoral victory since 1979. He was re-elected by a landslide in 2001.

He is a father of four children. His youngest, 4-year-old Leo, was the first baby born to a serving prime minister in 150 years.

The terms of British parliaments are for up to five years. While Blair would have to call an election by 2006, the next general election is expected to happen in 2005. If Blair is re-elected next year, he could remain prime minister through 2010.

Commentator Peter Stothard told CNN that the Iraq issue had put Blair under "extraordinary pressure" and that his family had been "fantastically supportive" of him.

In the United States, a senior Bush administration official said: "The Prime Minister is in our thoughts and prayers and we wish him the speediest of recoveries."