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.