(1) Is bisoprolol used to treat atrial fibrillation? (2) If a person becomes hypotensive e.g.102/55, 102/68, & 106/63 should he stop using bisoprolol?

Yes. This beta blocker is used to treat or control the ventricular response to atrial fibrillation. It can lower blood pressure and, of course, slow the ventricular rate too much(below 60). If you're experiencing side effects, discuss this with your physician or cardiologist who may lower the dose of prescribe another beta blocker or even switch to digoxin although this medication is less popular now.
Variables. several all is used to treat atrial through relation. I potentially does not automatically present with the kind of blood pressures you note in your question I potentially is when the blood pressure is too low for that particular person. This is usually shown by a feeling of weakness, and ability to stand up and get about normally. Those numbers above are actually ideal in a healthy person. HRS.