Blood Pressure as indicator of oncoming problem?

Hi everyone.
Every once in a while, I'll get a rush of dizziness or light-headedness, accompanied by mild nausea and general disorientation. I used to contribute this to a-fib, or the medication I'm taking (beta blocker Bystolic). I'm wondering if that is accurate, though.
My question is this....if it were something else coming on, like (and I know this isn't highly likely right now for me) a heart attack or something like that, would there be a noticeable change in blood pressure at that time? I ask because my bp and heart rate seem pretty normal when these "spells" occur, but I don't want to just write them off if it's possible that something else might be happening besides medication side effects.