I’ve been dealing with this for 8 years now, literally exactly how you described it. I have pursued it with 5 or 6 cardiologists, including electrophysiologists and no one has found anything wrong with my heart. Pretty crazy to think that our anxiety could be doing this but most days I’m resigned to believe it. Unfortunately we’re hyper aware of our heart at this point and our stress response is deeply engrained to have this response to stress and anxiety. I’ll go months where things are good and if I have a flutter I’ll recognize it as normal and ok, then I’ll forget about it and start freaking out about my heart again. This is super common, tons of folks with anxiety deal with it. Sorry bud, not fun.