I had one incident of syncope about two months prior to my first (of two) ablations. I had been getting more and more frequent episodes of AF, and my metoprolol dosage had just been increased on the advice of the gentleman surgeon who briefed me on the results of a preparatory angiogram (requested by the electrophysiologist who wanted to know if he was dealing more with ischemia than with a mere electrical disorder). He raised my dosage from 25 mg BID to 50. On this particular day, I had bent over, having sat and rested for maybe 15 minutes without rising, and picked up something from the carpet at my feet. I then stood and walked perhaps 10 steps and then a loud yammering, machinegunning, sound, happened between my ears. I felt myself slipping into unconsciousness and knew to get my backside low and onto the wooden flooring ASAP. I still fell with a thump, but I was fine. My head cleared, I never really lost consciousness. It was, as I stated, syncope, but it was positional...or so my EP offered when I mentioned it to him as he came to my bedside just prior to me being wheeled into the cath lab for the ablation. I think it was because I was very healthy, a life-long competitive runner with a very strong and fit heart, but the higher dose of metoprolol had but me in danger of low BP and then syncope. In fact, this is so common that it should be pointed out to both patients and their best buds with them to watch out for a heart in NSR, not fibrillating at the time, and its rate dropping into the high to low thirties...happened to me.