By MARLENE CIMONS

Los Angeles Times

WASHINGTON — Dick Cheney, the Republican vice presidential nominee, suffered what physicians described as a "very slight" heart attack Wednesday and underwent surgery to improve blood flow to his heart, providing yet another breath-catching twist in the political tumult that has been churning since the election.

Initially, doctors and George W. Bush declared that Cheney, 59 — who has a history of heart trouble — did not have a heart attack. But doctors revised their diagnosis after a later set of blood tests indicated a "minimally elevated level" in heart muscle enzymes. The presence of these enzymes indicates heart muscle damage — a heart attack.

In a brief telephone interview on CNN’s "Larry King Live" Wednesday night, Cheney said, "I feel good and everything’s looking good." He said taking the precaution of going to the hospital at the first sign of trouble "is one of the things that I’ve learned over the years. Anything that might be cardiac-related, you have to check it out. … That’s good advice for everybody."

Cheney’s health was the focus of much attention when Bush selected him last summer to be his running mate. At that time, Cheney had suffered three heart attacks, the first at age 37. He underwent quadruple bypass surgery in 1988.

On Wednesday, in explaining the change in their earlier diagnosis, doctors stressed that the definition of heart attack was changed last year by the American Heart Association to reflect "any enzyme elevation" measured in the blood.

"Over a year ago, this amount of enzyme elevation would not have been considered by most people signs of a heart attack," said Dr. Alan Wasserman, professor of cardiology at George Washington University Hospital, where Cheney — experiencing chest discomfort — checked himself in before dawn Wednesday.

"To put this into some perspective, in someone that has had a significant heart attack, the levels would be somewhere 20 to 50 times higher," Wasserman said.

On Wednesday, physicians performed a cardiac catheterization, inserting a permanent stent — a tiny scaffolding-like device — to widen a narrowed artery.

The Bush camp sought to downplay the potentially serious nature of Cheney’s hospitalization, putting a positive face on his condition and his prognosis and initially insisting — based on doctors’ views early in the day — that Cheney had not suffered a heart attack.

Bush, speaking to reporters in Austin, Texas, said, "We had a very good conversation. He sounded really strong. Secretary Cheney will make a great vice president … and America is beginning to see how steady and strong he is."

"Dick Cheney is healthy," he said. "He did the right thing. … Anybody who’s had heart conditions will tell you if there’s any signs, any warning signs at all, it’s important to have it checked out, and that’s what he’s done."

Bush and his aides dismissed questions about the stability of the GOP team, and whether they were considering alternatives should Cheney’s condition keep him from serving.

Asked whether it would be prudent to have a backup nominee, Bush spokeswoman Karen Hughes replied, "No, it’s not." She added that Cheney has had similar pains in recent years, but not since Bush picked him to be his running mate.

Doctors at the hospital said they did not believe that stress related to post-Election Day events contributed to Cheney’s heart attack — although stress is a known risk factor in heart disease. Cheney’s heart attack apparently occurred hours after Florida’s Supreme Court decided to permit manual ballot recounts in some Florida counties, a key victory for Gore.

Cheney, in the CNN interview, said he had "not found the last couple of weeks as stressful as, say, the Gulf War. … My time in the Pentagon during the Gulf War was far more stressful."

He said that his recent hospitalization should not affect his ability to serve as vice president. "There shouldn’t be any problems of any kind like that. Obviously, I always follow my doctor’s advice. … (There’s) no doubt about my serving. All we have to do is get elected."

Cheney’s doctors gave him a clean bill of health when Bush picked him. Still, there was speculation in an already chaotic situation over what would happen if Cheney had to drop off the ticket before the electoral college meets.

If Bush were president-elect, experts said, electors would be free to vote for another Bush choice, since they vote for president and vice president separately.

If Cheney drops out before the resolution of the election, Bush would be free to select a new running mate, and the Republican National Committee would likely gather to ratify his choice.

If the two already were sworn in, and Cheney died or quit, Bush would nominate a successor, who would have to be confirmed by the Senate and the House.