@ctholen I don't mean to come across as being argumentative, but it sounds to me, just based on your words above (and how I have interpreted them 😀 ) that you had a ....thankfully....rare episode of a tachyarrhythmia. I don't see how going off metoprolol, or even a reduction of the dose, made a difference unless it didn't have enough oomph at your new low dose to keep your rate lower than the 167 BPM you cite. At that high rate (I have gone as high as 180 !!!), it means your ventricle was also trying to keep pace, and it was careening away at that high rate. It's called RVR, or 'rapid ventricular response.' Those words 'should' appear on any formal diagnosis if you have a recent paper showing it.

Even so, I wouldn't dream of trying to tell you you're wrong; you know you best, and if I were you'd ask about an alternative like Sotalol or Diltiazem....they work for a lot of people, and one of them might be just the ticket for you.