I don't know of any contraindications of taking antibiotics with afib. There are some if you are on certain anti-arrythmic drugs like Norpace and Rythmol. I know, those warning labels are bad. It's a fine line between being informed and being scared to death. They have to put anything that EVER happened to anyone. I have found the pharmacy is a good advisor and also your family doctor. Your pharmacist should be able to tell you about any possible interactions.
I have multiple arrhythmias and have taken Cipro with no side effects at all. It varies from person to person which, as DeltaDawn mentioned, means they have to mention it.