After my aortic valve replacement with a mechanical one when I was 49 years old. (I'm now 77), I developed permanent A.P.C. (Atrial Fib) 24/7. In addition I get palpitation occasionally. Sometimes my heart beat gets loud or speeds up for no reason. Every two years I'm on a holter monitor for 3 days. Yes, at times the atrial fib feels uncomfortable. However, I plan to add another 15 years to my life for sure. I would suggest, try to get used to the atrial fib. Trust your cardiologist.