Beta Blockers and Vaso Vagal Syncope

Hi there.  I recently had a positive tilt table test and my cardiologist prescribed metoprolol 25 ml. once a day.  My resting heart rate is sometimes in the 50s and I was worried that it would get too low if I took the beta blocker.  Also, is taking a beta blocker the best medicine for my particular case?  In general, I was feeling lightheaded and did actually faint a couple of times.  When I went to the ER they said I was dehydrated and I was given saline.  I don't drink alcohol, caffeine, and drink a lot of water.  All my friends were in the same environment I was in AND drinking, with no problems. Then there's me...passing out and feeling lightheaded.  All my blood work (of course) came back normal.  Thanks for your time.

[Cleveland Clinic]

Positive tilt table test usually implies that you have vasovagal syncope.  Beta blockers are excellent for this.  It is unlikely that they will lower your heart rate much lower than that.  

[johnny138]

Thank you so much for responding.  If you wouldn't mind another question: the particular beta blocker I was on (metoprolol 25 mg) made me really nauseous, made my heart actually race when I took it, and have me a headache all day.  Is there a chance another beta blocker would be different?  Or is there another form of treatment I can look into?  I just don't really understand how the beta blocker helps prevent vaso vagal syncope.  Has it been proven effective?