Twenty years ago my doctor told me I could expect to live another 20 years.

Well, that’s not exactly what he said. After Laurence Kelley had propped open the blocked artery in my heart — threading a mesh stent up from my groin — and my heart attack was over, he announced that my prognosis was very good.

“I expect you’ll be around to see your kids graduate from college,” he said.

“Graduate school, too?” I croaked.

Does that sound greedy?

As it happened, both my daughters did go to graduate school. And — so far — I’ve kept on living.

Last Saturday was the 20th anniversary of my heart attack at age 38. I used to think about July 17, 2001, almost every day, replaying it in my mind: I was on an exercise bicycle at the YMCA. I started to feel lousy. My chest hurt. I was sweaty. I drove home and announced to my wife, “I think I might be having a heart attack.”

When the EMTs were slotting me into the back of the ambulance that my wife had summoned, one said, “So you thought you were having a heart attack, and you drove yourself home from the YMCA? We’ll pick you up anywhere, you know.”

Life is full of teachable moments. What I learned in that one was that EMTs enjoy treating people. They don’t consider it an imposition.

At Washington Adventist Hospital, an emergency department doctor checked my vitals while a clerk checked my insurance. I was scared, in pain and, frankly, not looking my best.

I didn’t see my life flash before my eyes, but I did think I might die. I found this both unfair and banal, like when your bag of Fritos gets stuck against the vending machine glass. I asked myself: “What did I do to deserve this?” And I answered myself: “Nothing. People die every day. July 17, 2001, could be the day you do.”

And then I was whisked into the cardiac catheterization lab where Dr. Kelley embarked on his journey up the Congo River of my circulatory system and straight to my heart of darkness.

Illness is a crime against the body and, as with any crime, detectives seek to understand it. People were curious why I’d had a heart attack so young.

It was easy to explain the immediate cause: a bulge of fatty plaque in my left anterior descending artery. It was harder to explain the cause of the broader cause. I was fairly healthy. I didn’t have high blood pressure. My cholesterol was a little high, but not frighteningly so.

I didn’t have a family history of heart disease. (Regrettably, I sort of pioneered one. Since my heart attack, my brother and my mother both had cardiac issues that required stents.)

My body was pretty beat up by the heart attack: dead muscle in the organ itself, bruises where the nurses and doctors had gained access. What surprised me was the effect on my mind. For months after my heart attack, I’d find myself crying for no apparent reason. I didn’t like to sleep in the dark or watch TV shows about sad or suspenseful things.

That was back when I thought about July 17 every day. It probably took a year before I would realize, “John, you haven’t thought about your heart attack for a few days.”

Then a week or two could go by. Then a month. Then I thought about July 17 only on its anniversary. My morning beta-blocker pill and my nightly statin became just a part of my daily routine, more like brushing my teeth than an artifact of the temporary platelet pileup in my heart.

And then this year, I forgot about July 17 entirely. Well, almost. This morning, I was looking through my wallet when I came across the stent implant card the hospital gave me. Someone there had neatly inked it with the date of my angioplasty.

So, 20 years (and a few days) later, what have I learned? What wisdom can I pass on? Well, life is random and so are death and near-death. That isn’t encouraging, but it seems like valuable information. It’s impractical to live every day as if it’s your last, but if you’re on the fence about something you’ve wanted to do, sooner might be better than later.

Also: If you think you’re having a heart attack, dial 911. They really don’t mind picking you up.

Twitter: @johnkelly

For previous columns, visit washingtonpost.com/john-kelly.