Hi GranRon-
I just started taking bystolic about two weeks ago. While I'm on a very low dose (2.5mg/day), it still seems to be pretty effective in keeping me out of A-fib. I've been on metoprolol before, and had some awful side effects with that one, but the bystolic seems to tame those down quite a bit for me. I've only had two instances in which I could tell I was experiencing some slight side effects (dizziness, slight shortness of breath, pressure).