@rice Well....I don't have any data on your ECG under stress, which running is. I also am not a qualified medical expert in anything....no training in medicine. However, I do know that if your heart insists upon such a high rate as 173, and you push it up to that level, either you're running too hard or your heart is fibrillating instead of beating in normal sinus rhythm. Either way, it's a problem. Your claimed heart rate is too high for your age....according to that rule I mentioned. You should at most reach for about 145. But you should really consult a qualified cardiologist and let them know what's going on when you exercise.

Also, you should have been put on a DOAC unless your risk of a stroke is deemed to be very low. A DOAC is a direct-acting oral anti-coagulant (Xarelto or Eliquis). Patients with AF have about a 4-6 times higher risk of stroke than they would with their heart beating in NSR. Also, in order to keep your heart rate under control, cardiologists normally prescribe a rate control medicine like a beta or calcium channel blocker, something like diltiazem or metoprolol. With your high rate, I would have expected you to say you are on one of those two, maybe bisoprolol....something to control the rate.