That's the million dollar question, Kris. I think everyone's individual body is so complex and interconnected that the things that might trip something in one won't do it in another. I know that for me, stress is the primary cause, and while the other factors like diet may play a role, it isn't the lead.
I know that withdrawing from activities that are known to reduce stress, like exercise, can only make things worse, because now that stress just accumulates. But then how do you exercise when you're afraid to?
I had a client back in 1999 (the first year I had
PVCs) that was so frustrating and infuriating and worrying that when I'd pick up the phone and it was her, my heart would start skipping around within 5 seconds of recognizing her voice.
I'm glad you're feeling better. In time I hope to research most every cause and remedy for these things and put it into a comprehensive list for people to use.