Someone you know fell in love slow-dancing to Barry Manilow tunes. So it’s ironic that with four decades of No. 1 love songs, the singer struggles with atrial fibrillation (A-fib), an irregular heartbeat that can lead to heart failure. Now, Manilow’s speaking out, encouraging others with the ailment to mend their broken (but not irreparable) hearts.

Why did you get involved with the “Get Back in Rhythm” campaign?
I want people to know that if their heart is going wacky and out of rhythm, they need to see their doctor and take it seriously. I didn’t realize there were so many people who have A-fib. I don’t like talking about my health or my personal life, but I wanted to be public about this [disease] and help somebody.

Have you ever gone into A-fib on stage or in an interview?

One time, I was scheduled to do a show with the Boston Pops on July 4. I was the headliner, and I woke up in the morning and felt this thing starting, and I couldn’t believe it. It got more and more violent, so doctors had to shock my heart back into rhythm with paddles. You know, “Clear! Bang!” When I woke up, my heart was back in normal rhythm, and I went to sound check and nobody knew that it had happened.

Has it interrupted your touring?

Well, it’s affected my lifestyle, because I don’t know when it’s going to hit. I’ve had it for 15 years, and it can hit at any time. I can’t predict it. It has nothing to do with stress — I can’t tell you how many times I’ve had those paddles. That’s why I’m trying to get the word out.

Speaking of hearts, you’ve been singing love songs since the ’70s. Do you think about how you’ve influenced so many love stories?
Over the years, I’ve realized the impact I’ve had. It humbles me. I get the letters that tell me that I’ve comforted people, that the music has done great things for them. When you do what I do, you don’t know what your impact is going to be. Over the years, I’ve realized that it’s made a difference.

You’re also known for your ’70s fashion sense.
Was there ’70s fashion sense?

Of course! And disco is back in style. Are you happy your decade is hip again?
Oh, no! Not those platform shoes! [Laughter.] Disco’s been here forever. It comes back in different forms, but it’s the same four-on-the-floor beat, [even though] it always sounds different. But dance records will always be popular.

You grew up in Williamsburg, Brooklyn, before it was fashionable. Are you surprised that Williamsburg is so hip now?
Oh, yeah! Taxi drivers wouldn’t even take me home when I said “Williamsburg.” It was so dangerous. When I was there, you wanted to stay away.