This is the first time I've ever heard of it happening.

However, in all truth and seriousness, I have never heard of it happening before.

I've never heard of it happening, though, if that's any consolation.

Fisk had heard of it happening that way: not during exertion, but just after.

I've never seen it actually happen, nor ever heard of it happening.

Maybe he just died from the exertion of running; I've heard of it happening to young people.

Claire had only heard of it happening twice before in their entire history.

I told him I'd heard of it happening once.

But I've never heard of it happening to bulk water to anything like that extent.

I have never heard of it happening before.