When I was first put on bisoprolol. I had to go to me GP on the third day because my BP was low and I had no energy.
My GP said it would be ok to come off it until I see the cardiologist because I was no longer in AF. I felt much better straight away.
Why is it we need to take it when we aren't in AF ?
Well, few of us on here are doctors or otherwise qualified to answer your question. However, my limited understanding is that 1) a lowered heart rate tends to reduce the incidence of AF getting started, 2) the bisoprolol in your system limits the extreme high rates that can occur when AF does start. e.g. my first attack reached 280bpm on the paramedics ECG due I suppose to me thinking I was dying and being very scared. Since then, and taking the bisoprolol, I've not to my knowledge exceeded 200 bpm (I have a Kardia).
76 years old with A F
apixaban and hematuria 
shortness of breath
3% Afib burden and proposed medication
