The pain was all wrong.

If this were a heart attack, the pain should be on the left side. Everybody knows that. It should be shooting down the left arm. There should be shortness of breath, sweating.

On the morning of Feb. 24, Larry King felt none of those things. He awoke at 4:30, about an hour after finishing his nightly radio show, with what he now describes as "a severe toothache in the shoulder" -- his right shoulder.

First he tried nitroglycerine. A heart patient for seven years, King was familiar with the pain of angina, caused by a temporary shortage of blood to the heart during exertion. This pain was different, but maybe nitro would work just the same.

The pain subsided for 15 minutes.

But then it was back, worse, more frightening.

On the hunch -- or in the hope -- that what he had was indigestion, he took the antacid Mylanta. Oddly, the pain went away again, only to come back, and go away, and come back, for the next two hours or so. There were calls to the cardiologist and, finally, a nervous car ride from his Arlington condo to George Washington University Hospital.

By 9:45, he lay in the emergency room, his body wired for an EKG, the pain getting worse -- "nine on a scale of 10," he would say later.

But this couldn't be a heart attack.

For 33 years he had smoked two and a half packs a day but the thought that he was doing damage to himself never sank in. For seven years his doctors had told him he had heart disease. But he continued to smoke, ate what he pleased all the while, denying that he was among the world's leading candidates for a heart attack. For five hours that morning, he "knew something was really wrong," but certainly it wasn't a heart attack. "Not me."

On Feb. 24, at age 53, Larry King's years of denial were over.

"Look, you're talking logic," he says.

King is back in his element now, the Mutual Broadcasting System studio in Crystal City, four weeks after the attack, and he is trying to figure out how he could have been so stupid for so long. The guest will be arriving in 34 minutes for "The Larry King Show," coast to coast on 300-odd stations, and there are promos to be recorded, a sportscast to be ad-libbed, mail to be read.

All week, listeners have been calling to ask how he feels. It is his fourth day back, and his fourth radio program without a cigarette. "Don't miss 'em," he says, amazed and thankful.

"Let's take a center fielder with a bachelor's degree, and Willie Mays, who went to seventh grade." King is making a point, and sports is his passion. "Willie Mays never in his life threw to the wrong base. Never to the wrong base. The college graduate? Many times threw to the wrong base. Explain that.

"I don't think it has anything to do with brains," he says. "I had angina. Logically, I knew I shouldn't smoke. But knowledge was of no use. I liked it too much."

That King is alive today can be attributed to a number of factors. He got to the hospital shortly after his heart attack began. It was a minor heart attack; he might even have survived it without treatment. And he received an experimental drug, tissue-type plasminogen activator, or tPA, which dissolves the blood clots that cause heart attack {see box, Page 14}.

Doctors know that a heart attack has much more to do with plumbing than with the heart itself. A network of vessels covers the heart, providing it with blood and oxygen. The narrowing of those vessels causes the relatively minor heart pain known as angina. When a narrow vessel becomes completely blocked by a clot, a heart attack occurs and heart muscle begins to die. Restore the flow, and damage to the heart can be limited.

Because tPA is still experimental, a patient must give consent before it can be used. It is available at two dozen medical centers, although federal approval -- and widespread use -- is expected by year's end. It is delivered intravenously over several hours.

"It's hard enough to do what we do," said Dr. Richard J. Katz, one of King's cardiologists, who treated him in the emergency room. "Signing up someone for a research project in the middle of a heart attack is no picnic."

"They have you all hooked up," King recalled. "The bag is hooked up, and he's reading this {consent form} to you. As soon as -- I mean, they knew I was going to say yes -- as soon as I wrote 'King,' it went right in."

It was just then, as the tPA began entering his system, that King realized he'd be making some important changes in his life. ::

On the air, first day back:

"Okay, we'll hit some calls here. Riverdale, New York. Hello."

"Hi, Larry."

"Hi."

"This is your pal, and I'm very happy that the Rembrandt of radio and TV broadcasts is back on the air."

"The Rembrandt of Radio -- oh, ho! Impressive, impressive."

"That's you, Larry." ::

After the heart attack, King suffers a typical case of post-heart attack depression. It comes with the realization of one's mortality. You leave the TV on so as not to feel alone. Wish you were married. "I take long walks now," King says, "and I think, 'Why am I taking long walks?' and then you remember.

"You just shake yourself out of it."

King had been through a life crisis before -- a financial one. In 1979, $350,000 in debt, he declared bankruptcy and put his financial life into the hands of agent Bob Woolf. "I used to think I'd always be in financial trouble," King says.

With the help of Woolf, his situation improved. Now -- between the radio show, his Cable News Network television show and his column in USA Today -- he earns more money than he needs.

Comparing those two life crises -- the bankruptcy and the heart attack -- he says, "I'd make the heart attack much more major."

But King is following his old pattern. When in trouble, turn to the experts. Do whatever they say. It worked with his finances. King now says he is taking control of his health crisis with help from different kinds of experts: his doctors, his nutritionist, his exercise coach. He's a good patient. He walks every day. He takes an aspirin to thin the blood. Although he dislikes alcohol, he has a daily drink because some studies show it benefits the heart. No more fatty foods. And, of course, no more smoking.

King talks with the excitement of someone who has just discovered a new world.

"I've lost 10 pounds while I've stopped smoking," he says. "I can tell you what I eat, mostly. I eat low-sodium cereals, like wheat puffs and rice puffs, skim milk, a lot of matzoh -- I love matzoh crackers, with margarine -- lettuce and tomato salads, and either fish or chicken, and baked potato."

All those foods are low in fat and sodium, a diet recommended by experts for everyone but especially for heart patients.

King can be seen almost daily at some of Washington's power restaurants -- like the Palm, Duke Zeiberts and Joe & Mo's, not known for their lean style of cooking. "They're all ready for me," he says. "Duke has got this roast chicken where they take off the skin. The Palm and Duke's both have the low-fat mayonnaise that I can use on lettuce and tomato salads."

He's about to begin a supervised exercise program three times a week to bolster his cardiovascular health.

Mostly, King is amazed that quitting cigarettes came as easily as it did.

"All I can be is honest. I do not miss it. I don't climb the walls for it.

"Yes, it took a heart attack. Absolutely," he says.

No more cigarettes for the 2 1/2-pack-a-day veteran. A snap.

"I'm thrilled that I don't miss it. I don't know what I would have done if I did. Now, I don't know if this is some psychological thing imbedded in me -- I will never forget that morning.

"So I gotta figure that the fear of God is in me. That I'm scared to death." ::

"West Chicago. Hello."

"Okay, I just wrote you a poem within the last five minutes while I was waiting on the phone so I want you to hear it."

"Okay."

"The entire country really cares / whether or not Larry airs / We all want you be around / so we can hear your wonderful sound / Be strong, my friend, and please stay well / 'cause without you it would sure be, uh . . .

"Go ahead, you can say it."

"Hell." ::

Until the electrocardiogram was performed, not even the emergency room personnel were sure King was having a heart attack. Right-side pain is not unheard of in a heart attack, but it is unusual, heart experts say. One physician told King he probably had gallstones.

When King learned the truth, his first thoughts were: "Am I going to die? Will this pain go away?"

And he thought about his 19-year-old daughter Chaia, who lives with him. He did not wake her the morning of the heart attack, and now wonders if he should have.

"And she's a smoker," King says. "She's typical, boy. I think the biggest smokers in America are 20-year-old girls. And now, what she won't do is this -- she still smokes -- but she won't smoke in front of me.

"I say, 'Chaia, look, you wanna smoke? You know the odds. You have greater odds because your father has it. You wanna smoke? I ain't gonna pull it out of your mouth. And you might as well come in and smoke in front of me.' But she doesn't.

"She says she's trying to stop."

One thing King is convinced of, however, is that preaching will not make anyone quit cigarettes. It won't make people take preventive health measures, which is why he talks about giving up smoking on the air with some reluctance -- primarily because his doctors told him he could "do some good."

King himself had been preached to for years. Dr. Michael DeBakey, the heart surgeon, urged him to quit the last time King interviewed him. So did Surgeon General C. Everett Koop -- the day before King's heart attack.

So did Angie Dickinson, who King is dating. "She was having an effect on me. We'd be driving in a car, I'd light up, she'd open the window and stick her head out. Subtle.

"She knew David Janssen very well. Loved David Janssen. And he smoked five packs a day and just dropped dead one day." ::

"Gilbert, Arizona. Hello."

"Hi, Larry. I'm a first-time caller. I just wanted to call up and wish you well, and tell you that I've traveled all over the country in the last couple of years and it's been really nice just to have someone there, a friendly voice to hear when you're in different cities and sometimes you don't know anyone."

"Well, thank you."

"And another thing. What do you think of the Cubs this year?" ::

King has received more than 2,000 letters from well-wishers. "Everyone from Frank Sinatra to Kitty Kelley," he likes to say. Not to mention Edward Bennett Williams. Paul Simon. David Letterman. Raymond Burr. Joan Rivers.

He has eased up on his schedule. Instead of doing four hours of live radio, he does three. He has canceled speaking engagements as well. "Getting a little tired," he told listeners as he began the third hour on his first night back. "Gotta admit that, folks."

Last Tuesday, Katz and Dr. Warren Levy, another of King's physicians, were the guests on his late-night radio show.

"I ask this to try to help the audience as much as myself," King said at one point. "Is it possible, in a perverse way, that my heart attack -- and some heart attacks of people like me who smoke and don't pay much attention to health -- are in effect blessings?"

Could be, Levy said. "If they're small heart attacks, it may be the very first warning that you have underlying heart disease of a serious nature."

"Would you say it benefited me?" King asked.

"What do you say?" the doctor asked back.

"Well, I feel good. People come over and say you never looked better. It's weird, but I guess in a sense it did. But I suffered for it, right? I do have muscle damage."

"You've had muscle damage," Levy said, "but ever since we came in tonight you've been saying, 'Gosh, I've never felt better, I feel wonderful, I'm exercising, I've stopped smoking.' You're a new man."

"Yeah." King paused for a breath. "Would have been better without it, but . . . Baltimore. Hello."