My cardiologist has suggested this drug for my persistent a-fib. I am hoping to discuss its effects with someone already on this medication. ## Much depends on the background of your a. fib, but if you do not have any outstanding other cardiac issues (as I do not), you probably do well on this. I have had no major side effects (unlike every other rate/rhythm drug that I took) so far. I have been on it nearly two years. I do think I am a bit more fatigued than ought to be, but much better than with the a.fib. I also notice a little bit trouble staying asleep at times. Unfortunately the drug seems not to be controlling all the aberrant a. fib, because I must occasionally supplement with metoprolol this past year. I have been told that the drug eventually fails for most folks over time as ...