Your comments are right on! One size does not fit all! And good for you PCP for over-ruling the cardiologist if he knows your situation better and is concerned about all the Black Box warnings that come with stronger meds! I take Diltiazem since I was diagnosed with A-fib and it has worked for me--I actually lost weight. I am betting that the reason you are doing better on carvedilol is that your blood pressure is in control and losing weigh often helps the A-fib too! I think you are smart to listen to your body and not just believe another pill will solve your issues. I tried the anti-arrhythmic med for two weeks and that was it for me! Once I looked up the side effects and the warnings, I said it wasn't worth it, if it was even really doing anything anyway. I am choosing an ablation soon.