As of yesterday, there was no sign that Fumo, 64, who has a history of heart problems dating to childhood, planned to withdraw from the race in the First Senate District, which extends from Philadelphia International Airport to Port Richmond.

"It's certainly going to curtail his activities in the short term," Fumo spokesman Gary Tuma said. "But beyond that, I don't have an indication that it will affect his long-term goals."

Asked whether Fumo, who faces trial in the fall on federal corruption charges, would continue to campaign, Tuma said: "I haven't heard anything to the contrary."

A day after Fumo suffered the coronary, the Democratic legislator's office said he was conscious and alert but in some discomfort at Hahnemann University Hospital, where he is expected to remain for an "indeterminate period."

Fumo's three opponents in the April 22 Democratic primary - neighborhood activist Anne Dicker, union leader John J. Dougherty, and lawyer Larry Farnese - all expressed wishes for a speedy recovery.

Dicker sent Fumo flowers and Dougherty postponed his scheduled campaign launch from today until Thursday "out of respect" for his opponent.

Gov. Rendell, who has said he would endorse Fumo because of his legislative record, "is certainly concerned about Sen. Fumo's well-being and wishes him a speedy recovery," spokesman Chuck Ardo said.

Sidelined since undergoing back surgery on Feb. 19, Fumo has not been able to take part in budget hearings before the Senate Appropriations Committee, on which he sits and which he headed until he resigned last year in advance of his federal indictment.

He also is not expected to be in Harrisburg when the Senate returns to full session Monday to begin considering a package of bills related to mortgage foreclosures, the creation of a do-not-call registry for political phone messages, and limiting public benefits for illegal immigrants.

Fumo, first elected in 1978, is scheduled to go on trial in September on a 139-count federal indictment charging him with conspiracy, fraud, obstruction of justice, and filing false tax returns.

Yesterday, Fumo's lawyers filed new challenges to the case against him, the first substantive pleadings in the case in almost six months.

In one filing, they asked a federal judge to throw out the evidence obtained from three searches, including a 2005 investigation of Fumo's legislative office in South Philadelphia.

The lawyers, Dennis J. Cogan, Peter Goldberger and Stephen R. Lacheen, argued in part that that one search warrant was improperly over-broad, permitting the FBI to "rummage through Sen. Fumo's papers, records and computer files with seemingly complete freedom."

None of Fumo's primary challengers indicated they would consider using his health problems as well as the federal case against him as issues in their campaigns.

G. Terry Madonna, director of the Center for Politics and Public Affairs at Franklin and Marshall College, said using the health issue would not be a good idea.

"The health thing is really, really tricky," Madonna said. "Generally, that is not the best way to go. You run the risk of being accused of piling on. . . . It could easily backfire."

The powerful legislator was recovering from back surgery - his second in four months - when he suffered the heart attack Sunday while eating dinner with his family at his Spring Garden mansion.

Taken by ambulance to Hahnemann, Fumo underwent emergency angioplasty and an insertion of a metal stent to open a completely blocked right coronary artery.

Alfred A. Bove, chief of cardiology at Temple University, who has not been involved in Fumo's care, said the senator's case illustrated why it was important for patients to get quickly to the nearest hospital that can perform an angioplasty to restore blood flow to the heart muscle.

In an angioplasty procedure, a catheter is threaded through an artery from a small incision, usually near the groin, up to the blockage. There, a balloon is inflated to restore blood flow. Often a stent - a small wire-mesh scaffold - is used to prop the blood vessel open.

Bove said a person suffering a heart attack might return to work in as little as a few days or up to six weeks later, depending on the extent of damage to the heart.

Fumo's latest back operation involved a lumbar fusion to correct misaligned vertebrae.

Fumo grew up with a congenital heart defect and underwent heart surgery at the Cleveland Clinic to repair a leaking mitral valve in 1996.

He has been hospitalized for angina, a chest pain due to a lack of oxygenated blood to the heart.

Contributing to this article were Inquirer staff writers Mario F. Cattabiani, Josh Goldstein and Craig R. McCoy.