he presidential campaign of Bill Bradley was briefly put on hold yesterday when he canceled all appearances in California and checked himself into a hospital because of an irregular heartbeat.
A Bradley aide said the former New Jersey senator ''felt a little different'' Thursday night because of the heart condition. Bradley hoped the problem, which was diagnosed in 1996, would correct itself as it has in the past, and attended a campaign event yesterday morning in Sacramento.
But by afternoon, Bradley checked into a hospital near Palo Alto, Calif., and met with Dr. Edward Anderson, a cardiologist. According to a campaign spokeswoman, Bradley had expected to receive a mild electric shock to the heart, a treatment he has received in the past. But Anderson said that before Bradley arrived at the hospital, ''he had converted to a normal heart rhythm and no therapeutic action was needed.''
Voters expecting to see Bradley in nearby Berkeley were instead read a statement by the candidate. Bradley, 56, was staying overnight in California, but not in a hospital, aides said. He has canceled his appearances in Washington state today, but plans to resume his schedule tomorrow, with a trip to Orlando, Fla., to address the state Democratic Party convention.
Heart specialists said the condition should not hamper Bradley's campaign. The candidate's aides quoted his personal physician, Dr. Robert H. Heissenbuttel, as saying it ''would not in any way interfere with his ability to function.''
Still, news of the condition, which had not been disclosed until yesterday, promised new scrutiny of the candidate. Political analysts said voters would be watching Bradley carefully in the coming days, concerned with whether he can manage the strain of the campaign trail, let alone the presidency.
''I think it's a problem anytime a presidential candidate has a health problem that requires hospitalization,'' said Darrell M. West, a political science professor at Brown University. ''Voters will be asking, `Can this guy handle the rigors of the job?'''
John J. Pitney, a political scientist at Claremont McKenna College in California, said voters would be concerned only if the heart problem is a serious one.
''If it's a minor problem, then it shouldn't have a serious impact,'' said Pitney. ''After all, we reelected Dwight Eisenhower after his health problems in the '50s.''
Eisenhower suffered a moderate heart attack in 1955, although it was not fully revealed to voters before his reelection the next year. Also in 1955, Lyndon B. Johnson had a heart attack when he was Senate majority leader. Johnson was elected vice president in 1960 and president in 1964.
But when former Massachusetts senator Paul Tsongas ran for president in 1988, he provided a rosy picture of his health after a serious battle with cancer. Tsongas suffered a relapse and died in 1997.
Tsongas's experience has led many candidates in recent years to release detailed medical records in order to prove that they are healthy and physically capable of holding the highest office in the land.
Last week, Arizona Senator John McCain released his medical records in order to rebut whispered suggestions that he may have suffered mental impairment because of his 5 1/2 years in a North Vietnamese prison camp.
He also reported having a cancerous mole removed from his shoulder in 1993.
Atrial fibrillation, an irregular beat of the heart's upper chambers, is a common condition, affecting at least 2 million Americans. It can be caused by many factors, such as an overactive thyroid (the cause of former President George Bush's atrial fibrillation), high blood pressure, and some medicines. But most of the time, specialists said, there is no known cause.
Unlike potentially deadly ventricular fibrillation, which affects the heart's main pumping chambers and was linked to the death of basketball player Reggie Lewis, the condition that Bradley has is usually not life-threatening.
The main risk, specialists said, is that a clot will form within the heart because atrial blood flow stagnates. Even a tiny clot in the left atrium can cause a stroke if it migrates to the brain.
For that reason, patients with persistent atrial fibrillation are routinely put on blood-thinning drugs. Sometimes a short electrical shock is used if the atrium does not spontaneously revert to a normal rhythm.
Dr. Deeb Salem, chairman of medicine at New England Medical Center, said Bradley's atrial fibrillation is likely to be ''a minor inconvenience'' for him.
Dr. James E. Muller, director of cardiology research at Massachusetts General Hospital, agreed. ''There are many people in important positions who have atrial fibrillation,'' Muller said. ''If all he has is AF, it is not a significant factor in his capability to perform the job of president.''
Last night, Bradley's cardiologist was similarly describing the candidate's condition as ''more of an inconvenience than a problem.''
The Bradley campaign also released results of a recent physical exam, which showed no other sign of disease and no structural damage to the heart. The exam reported about a half-dozen incidents of atrial fibrillation since 1996, three of which were treated with a mild electric shock. Bradley was also prescribed the antiarrhythmia drug Procanbid to prevent or shorten the duration of the episodes.
Vice President Al Gore's campaign had good wishes for a speedy recovery. ''Our hearts and thoughts and prayers are with Senator Bradley,'' said Gore spokesman Chris Lehane.
Next week, Bradley is to travel to Claremont, N.H., to meet McCain and shake hands on the need to overhaul the campaign finance system. On Friday, he is scheduled to meet Gore in a forum at Daniel Webster College in Nashua.
Material from the Associated Press was included in this report.
