I rarely notice when I am in A-Fib as well. Mine is naturally occuring so having had it my entire life it's a bit 'normal' for me not to notice. I am usually only aware when I have a new EKG or when my heart sort of seizes up for just a moment like it's pausing to hold it's breath and flops like a fish out of water. That one I notice. I was diagnosed with A-Fib and also Postural Tachycardia Syndrome. Mayo can do a tilt table test that will be able to record whether or not certain positions cause you to jump into A-Fib. I simply started taking the Metoprolol and was very lucky that the first med I tried works perfectly.