I can believe your doctor would say such a thing. Just another way of saying I haven't got a clue and I am a clueless clown selling drugs pretending to be a healer and making lots of money.
I have been doing some research and no one seems to have hit on this but my condition started about 1995 shortly after having two root canals with posts to secure my caps. I have a strong suspicion that dental procedure started my a fib. I will find out tomorrow when I have them pulled and replaced with implants.