In an era when baboon hearts are implanted in babies and polyurethane hearts in adults, it's important to be reminded that most of us are stuck with our own.

Jim Lehrer does that, and much more, in "My Heart, Your Heart" (tonight at 8 on Channel 26), a compelling documentary held together by the story of Lehrer's own heart attack 14 months ago at age 49.

In no-nonsense, staccato sentences, Lehrer, coanchor of "The MacNeil/Lehrer NewsHour," describes a three-month ordeal that began on a Sunday morning with what he thought was indigestion.

I woke up with tightness in my chest. It was a dry tightness, like sand. I could almost smell it. It wasn't that painful, just uncomfortable. Very uncomfortable, like somebody had their foot on my chest and wouldn't take it off.

The tightness lingered, along with a tingling in his left arm, and by midnight he was on his way to the hospital. A day of tests revealed no obvious problem, and Lehrer went to sleep thinking he'd be back at work in a couple of days.

I awoke at about 5 the next morning, with the feeling a big truck was rolling back and forth over my chest . . . The pain was terrific. I was sweating profusely . . . And after a while, just as suddenly as it began, it was over. I lay my head back down on the pillow. I felt all right. Then, and only then, did the wonderful nurse say, 'Mr. Lehrer, you just had a heart attack. It was good you were here when it happened.' "

That night, Lehrer and his wife, Kate, were in an ambulance headed for Georgetown University Hospital, where he would undergo a coronary bypass operation to restore adequate blood flow to his ailing art.

It was raining and it was cold and dark, and I had tubes and needles and other things sticking out of me. We both broke down and cried. I had had a heart attack. What did it mean? My God, what did it mean? We didn't even know what a heart attack really was.

Lehrer learned the hard way. If you're an adult male, or know one, it's a sobering message: What often passes for the good life in America is killing people. One in five men will suffer a heart attack before age 60.

For all its colorful graphics and dramatic film of heart surgery, the documentary is carried by Lehrer's own story and the well-paced script he helped write. The tone is authoritative but not preachy, personal but not heroic.

Heart disease is the biggest killer in the United States, claiming 500,000 lives a year. It costs the nation $72 billion a year, not counting lost lives.

The statistics are big, but somehow numbing, and Lehrer seems to realize that. Just when "My Heart, Your Heart" threatens to bog down in an effort to discuss every coronary "risk factor," every stage of care, every culprit from cholesterol to Type A behavior, Lehrer pulls back and returns to his best source: himself.

For 30 years I was a smoker. For more years than that I was a steady consumer of deep-dish pizza . . . and very greasy Texas barbecues. Now I rarely even eat red meat . . . Most of the changes may sound like common sense, and they are, but it took a heart attack for me to make them.

Perhaps the most painful moment in the hour is a film clip from "Heartsounds," a made-for-TV movie. Actor James Garner, knocked to his knees by a pain in his chest, struggles to the phone and barely manages to dial 911 and stammer, "I'm having a heart attack."

"Nobody ever portrayed it better," observes Lehrer. And we know he knows.

Although Lehrer describes in considerable detail his own heart operation, this is no advertisement for bypass surgery. He gives a fair hearing to critics who call heart-bypass "a big moneymaker" for surgeons and hospitals and estimate that half of all bypass operations are unnecessary.

Lehrer has "no second thoughts" about his operation. But he acknowledges its high cost ($17,000 in his case, covered by insurance) and its pain.

I'm not going to play Lyndon Johnson and show you my scars. But rest assured: They are there, in the chest, down the legs and in my mind.

Sensibly, Lehrer does not dwell on the most highly publicized recent developments in open-heart surgery, such as the artificial heart. "For most of us now," he says, "they, along with Baby Fae and even human transplants, are irrelevant."

But his heart attack was all too typical, all too scary. For months, he was afraid to fall asleep at night. On out-of-town trips, upon checking into a motel, he would immediately look up cardiologist in the yellow pages. And he became a compulsive reader of the obituary page, checking ages and causes of death.

I considered it a good day when there were no men under the age of 60 who died of heart attack.

Lehrer's message is not new, and he admits it's one he ignored until his own heart attack: Prevention is the best approach to heart disease. The three biggest risk factors for heart attack -- smoking, high blood pressure and high-fat diet -- are all controllable.

I feel better now than I did before my heart attack. I have more energy and more stamina. My brain seems to even work better now than before. Why? I don't know for sure . . . But there's one thing I do know. It wasn't worth it.