Hello~First, I would make an appointment with a reputable Naturopath, they will be able to help you with this issue as they are trained in alternatives to drugs.
I have researched some alternatives to the drug, here they are:
•Coenzyme Q10 (CoQ10)
Also acupuncture and chiropractic adjustments can help with the a-fib.
Again, however, please check with a doctor that specializes in alternative options, your best one would be a naturopath, that was my main doctor back home, she helped with any and all issues.