I have had only one episode and that was during a stress test in the doctor's office. Prior to the test, he told me to STOP my beta blocker ( Atenenol 25 mg ) for 3 days. I did as instructed and after about 3 minutes on the treadmill I was having some serious arrhymias ( spelling ! ) including A flutter and A- Fib. I was taken by ambulance to the hospital and had a heart cath done the next day. No stents were needed but I did have some coronary artery disease.
I think my A - Fib was because of abruptly stopping the Atenenol and told my internist and cardiologist that...They never said if they agreed or not.
But I really believe the sudden stop of the medication was the trigger for me.