The ER is not the place for routine treatment. They are there to stabilize any life-threatening condition, then turn you over to the appropriate doctor for treatment. Your cardiologist needs to be addressing this. I'm not sure why he didn't discuss calcium channel blockers. If your heart rate is high (compensatory reaction to low BP) he may be trying to lower the heart rate with beta-blockers...when what you really need is to be properly diagnosed and treated for the low BP. Once the BP is treated, your spasms may improve. This other condition you mentioned with your blood vessels also needs to be addressed.

You say the cardio "mentioned" the beta-blockers, but you didn't say whether you were actually taking them (if they helped) or what the plan is. You haven't said what testing you've had to determine AN (tilt table, etc).

You should request to see an autonomic specialist...which may mean you might need to go to a teaching hospital or large medical center. Good autonomic specialists are not in run of the mill hospitals.