A tilt table test
will not be useful in this case. It is used to diagnose vasovagal responses (fainting
Beta blockers are commonly prescribed for the symptoms you are describing, and are usually effective in reducing the frequency and quality of your symptoms. Doses are usually started small, and increased slowly if needed so you have a chance to adjust to them. That way, your blood pressure should not be affected very dramatically. It sounds like you would be keeping track of your own blood pressure at home, so you would be aware of any severe changes almost immediately.
Your doctors sound like they are managing your care very well.
If you still feel a need to pursue more information, you may try to talk to an Electrophysiologist (a specialist in heart rhythms).
Also, you may find more information at the Heart Rhythm Society website.
Good Luck. :>)