Bradley campaign statement

The condition is more " an inconvenience rather than a problem," an adviser said.

"His spirits are good. He knows what this condition is. He handled it and he's in excellent shape," campaign press secretary Eric Hauser told reporters while Bradley was at an undisclosed hospital near Palo Alto, Calif.

Bradley, 56, went to the hospital expecting to receive a mild electric shock to the heart, a common treatment for the irregularity known as atrial fibrillation, said Anita Dunn, his communications director.

But later Friday, Dr. Edward Anderson released a statement saying that by the time the former New Jersey senator arrived at the hospital "he had converted to a normal heart rhythm and no therapeutic action was needed."

Bradley was remaining overnight in northern California, but not in a hospital, his campaign emphasized.

Describing the candidate's condition, Dunn said, "As his cardiologist told me, it's an inconvenience rather than a problem."

Three times before, Bradley had received the shock treatment -- known as cardioversion -- since doctors discovered his heart condition in 1996.

Bradley, who was in northern California on a two-day swing, felt symptoms Thursday night, Dunn said, but decided to proceed with his schedule Friday morning "to see if it would fix itself as it often would."

Bradley, who is challenging Vice President Al Gore for the Democratic presidential nomination, appeared to be in fine spirits Friday morning at a news conference on the steps of the state Capitol in Sacramento. He joked about the cold air, and at one point asked reporters to tell him if his nose had turned red.

Later in the day, Bradley attended a fund-raiser in Berkeley.

While he headed to the hospital, supporters waited beside the San Francisco Bay for more than an hour before aides announced his environmental speech there was canceled. Bradley was to have laid out his proposal for a new $250 million-per-year coastal and ocean conservation fund "to better protect and restore coastal and marine habitat."

Two evening fund-raisers in the Bay Area were also canceled.

Atrial fibrillation is a type of irregular heartbeat shared by some 2 million Americans, the campaign emphasized. "We are concerned about him because we care about him, but this condition won't change anything in the campaign," Hauser said.

After Bradley was first diagnosed, doctors used a small electric shock to return his heartbeat to normal. In May 1998, he was put on an anti-arrhythmic drug called Procanbid because the irregularity returned several times, as is common.

Those details were disclosed in a letter from Bradley's doctor, Robert Heissenbuttel, of Columbia Presbyterian Medical Center in New York, which the campaign also released Friday.

The letter said Bradley has excellent blood pressure and cholesterol levels and otherwise normal heart function. The doctor's notes from an exam last week indicated no other signs of disease. In April, Bradley had a small, benign polyp removed from his colon and tests indicated no signs of colon cancer.

Dunn said Bradley asked for this latest physical exam in response to standard press inquiries and had planned to release the results next week. The campaign moved the release to Friday to shut down concerns that the treatment might raise questions about his health.

Dunn said Bradley on Thursday night only "felt a little different." His doctors had advised that when he felt symptoms he could wait to see if they disappeared, so he campaigned most of the day Friday. He was scheduled resume his campaign schedule Saturday, flying to Florida in advance of a scheduled address to the state Democratic Party convention on Sunday.

Atrial fibrillation occurs when the heart's upper chambers, the atria, contract far faster than is normal, outpacing the heart's lower chambers, the ventricles. Atrial fibrillation is usually not life-threatening and in fact is much less serious than other irregular heartbeats, such as ventricular fibrillation, which can cause death.

Atrial fibrillation sometimes causes no symptoms, but when the heartbeat soars to extremely high levels, patients can feel palpitations, faintness and shortness of breath.

Former President Bush suffered a type of atrial fibrillation in 1991 as a consequence of his thyroid condition called Graves disease. There are many different causes of atrial fibrillation and Bradley's physician said he did not identify a cause.

AP Medical Writer Lauran Neergaard and AP reporter Scott Lindlaw contributed to this report.