It isnt surprising that this isnt the first time he has been in atrial fibrillation. It can occur acutely, chronically or intermittently. It comes back in many even after cardioversion. Ultimately he may eventually go on a beta blocker (like metoprolol) and a blood thinner (like warfarin). It isnt an issue that will prevent him from doing his job.
The comment from his brother about it being more advanced isnt entirely accurate. Atrial fibrillation makes your heart rate irregular. Basically, if you felt his pulse it would occur with variable time intervals between beats.
What his brother was likely referring to was that Jim had something called atrial fibrillation with rapid ventricular response. In other words, the atrial fibrillation was also causing his heart rate to run a bit high (likely 100s to 130s). So he had an irregular and also fast rhythm
[ Edited by diablo on Nov 16, 2012 at 1:12 PM ]