Are you on any medication to help control your heart rhythm? I know the sectral is only for blood pressure and the effexor xr is an antidepressant/anxiety medication. And as Jerry posted if you are having Afib I would think you would be taking an anticoagulant, even if just aspirin. If you are not taking one, I don't know what could be causing your nosebleeds unless your blood pressure is totally out of control. But no matter the answer you need to speak with your doctor in regards to the nose bleeds and find out what is causing them. A heart rhythm disorder would not cause your nose to bleed.
I don't recognize all the meds you are on but would not be surprised if one of them is an anticoagulant because of your AFib. If true, that could be a reason for the nose bleeding, anticoagulants have to be closely matched to your diet to get the correct amount of blood "thinning"... too much and bleeding can be the result. As said, I didn't see Coumadin or Warfarin in your note, and they are the only anticoagulants I know about and have/am taking.
Sorry the ablations having done the job of fixing the problem. I have read man post by people who have had several before getting the desired cure.