Hey sweetie, I know this is an old post but I had to write! This is so rare! I developed dysautonomia /IST/OI etc. First, then developed CHF (cardiomyopathy). My EF is improved now so this is so weird! I am sad your Journey is of rare presentation too, but hey at least we aren't alone, hey? *hugs* I have underlying pathophysiology of chronic active EBV & also CFS/CFIDS so I can relate to your situation. I would hypothesize that your CHF is not secondary to POTS but rather the same culprit responsible for your CFS remaining active and/or reactivating & causing the further damage. This happened to me. Please let us know how you're doing now. Much love & be well sweetie! Xoxox ~do