The condition was dismissed by his head of communications, Anita Dunn, quoting his cardiologist, as "an inconvenience rather than a problem", but it raised doubts about the prospects for Mr Bradley's candidacy with the first, and crucial, primary elections less than two months away.
Mr Bradley, a former Senator and basketball star, has emerged as an unexpectedly strong candidate in the past six months of campaigning, forcing Mr Gore to change strategies several times over. At 56, Mr Bradley is among the older candidates. Republican Senator John McCain, 63, released two volumes of his medical records this week in an effort to quash rumours about his health. Mr Bradley could now come under similar pressure.
Ms Dunn said Mr Bradley first felt the symptoms on Thursday night but proceeded with his programme yesterday in the hope that it would "fix itself as it often would".
That he felt obliged to cut short his west coast tour suggested that it did not. He had planned an appearance with Mr McCain for next Thursday and one with Mr Gore for Friday.