Mine 3 years ago was first at 470.. I was asymptomatic.. untill recently well I actually thought I had epilepsy having seizures in my sleep.. I got an iud placed in to help with my pmdd.. that's when things got serious my potassium was life threateningly low and my score went to 490.. but again like yourself it fluctuates. The doctors don't know much about this heart condition.. all I know it cab lead to svt or tdp! Which scares the hell out of me! How are you managing your symptoms when present? Because like I said 2 3 years ago I was diagnosed but never had a problem untill now.. please be safe and take care of yourself.. I feel so alone in this and I don't know what to do.. im on a beta blocker and 1.2 grams of potassium a day! I just found out my uncle passed away from this... but he did not take care of himself AT ALL! I'm hoping with the right life style changes and check ups I can avoid going into afib or set. I'm so sorry you have to go through this... you think they would have more research... some doctors are saying it's the leading cause of SIDS! They don't say much because again research is vague and I'm sure the doctor isn't trying to stress you out also, just being a good doctor knowing stress will throw you into a fib!