Heart attacks look much more painful in real life than movies and TV make them appear.
I can't help but agree. That, and I don't know how your impression relates to mine, but...
One morning I was walking into work, and there was a security guard laid down on a stretcher with about two or three paramedics around him. The rest of the lobby had maybe seven or eight other people, all of which attempted to go about our respective days while not staring at the man, who was gasping for breath and crying in pain that sounded extremely terrifying.
The scariest thing was probably the convergence of it all. Even though he had medical professionals surrounding him, attempting to alleviate whatever pain he was in, they couldn't. They just loaded him on, tried to talk him through it, while he laid there, crying in pain for some seeming elusive help. A certain powerlessness that was inescapable.
Though vicarious, the experience was not at all fleeting. I want to think he made it out OK, but I can't type that for certain.