I have non-heart related Atrial Fibrillation.
It physically express in me all kinds of heart related issues, from fatigue to being hyper, confusion and lack of concentration, COPD like shortness of breath, and sometimes minor heart attack like pain.
My heart beats fast, but my BP remains normal. Some of my friends with AFib tell me they think their having a heart attack, and they have the typical mild to sever pains.
Other's say they don't even know when they're having an attack.
Good luck and I wish you better health,