@sandw40 Perhaps not everyone, but the majority will. The rate varies, and it slows with management (drugs or a successful ablation, but sometimes a substantial improvement in lifestyle will work very well), but once the heart enters any kind of arrhythmia it's a sign that the heart is commencing to remodel itself. It's a sign that the heart is already electrically disordered, but just now the symptoms show up with enough of the rogue firing cells wanting to act to send a signal to the left atrium so that they take over the beating signalling....working against the SA and AV nodes which are supposed to do all that.

Once you understand that there are formally adopted stages to atrial fibrillation, they being paroxysmal, persistent, long-standing persistent, and permanent, you can see that it MUST be progressive in nature.
https://pmc.ncbi.nlm.nih.gov/articles/PMC5153232/