I am your age and have suffered from AFib for about 10 years, with periodic NSR after electrocardioversions. I have always reverted back to permanent AFib, which is my current state. I am not aware of any bloating or belching associated with my AFib.
I don't know if bloating or belching sets the arrhythmia off, but I do know of other people who have a problem with belching when they go into a-fib.