Thanks John. Your citations are helpful. The article by Maiuri et al. in Current Research in Neurology and Neurosurgery was quite interesting. Basically brain tumors sometimes bleed. In their series it was at about the same risk off or on anticoagulation. One thing for sure, with my age and other risk factors, afib definitely puts me at increased risk for thromboembolic stroke. So I'm going to do it. They are going to try to cardiovert me in a couple weeks. If that produces a permanent remission in the afib, I can hopefully downgrade the anticoagulation.