Oh my. That IS frightening, the only time I have had this was a drug reaction. The doctor blew me off, too, the arrogant....never mind.
I wish you a peaceful evening, that the temporary drug works, that you wake up feeling better tommorow, and that you find a cause and it is easily treatable. Change doctors if she is not looking for a cause.
Ask yourself what is different in your life right now, that will give you a start. And don't feel bad if everything is the same, you may have a genetic\physical glitch that just says your heart beats too fast.
I just wanted to tell you, if you feel faint, you go to the ER right away because they will take it more seriously.
