Hello. I have had one known bout of afib; at the end of January I went to the emergency room after near fainting and was told I was in afib. A later Holter and event monitor showed normal beating. I'm on aspirin and 50 mg toprol. From what I've read, I suspect that mine is vagally-mediated afib since a stress test turned up no adverse results, the passing out occurred a few minutes after getting out of bed, and I had a positive tilt-table test reaction. Can vasovagal syncope and vagal afib be tied together, since both involve the vagal nerve? Are there other special concerns if it is vagally-mediated afib? I have read that beta-blockers are not recommended with vagal afib, but my cardio says that it would still help with the ventricular response (and apparently it hasn't triggered another afib bout yet). My resting heart rate is already fairly low and is in the range of what they apparently see in athletes, but I'm actually very sedentary. Without toprol my resting heart rate can get down to around 54, with toprol I've seen it get down to 44. My cardio says that this really wouldn't be a problem unless it's symptomatic, but besides a lazy disposition I've no symptoms. Should I worry about the toprol? I used to drink a lot of coffee/tea/sodas but I cut way back on caffeine two days before the bout; could I have caused a vagal crash if my system had adjusted to an artificially-enhanced adrenergic tone? I'm 31, non-smoker, very light occasional drinker, vegetarian (ok cholesterol, but still too fat), blood pressure ok and no underlying heart disease found.