Thank you for describing it. I haven't had exactly that symptom. I suppose your doctor is a cardiologist or your primary? It is hard to know what specialist to ask about it. Why assume it is the AFib? (Maybe because I don't think I am aware when I am experiencing the AFib most of the time). That reminds me to check with this group and see if anyone ever has a dark shade come over half of one eye. Or blurry vision occasionally in one eye. Over the years, I didn't automatically assume these were migraine symptom, because the migraine-related visual disturbances (usually called aura) I have had in the past is more like fractured vision, like not seeing all the words on a page because of spots. Usually preceded by headache, nausea, but not in recent years. Very confusing to figure out cause of symptoms -- whether heart, brain, or eye symptom.