Well if you have seen lots of docs and got the word that there is nothing wrong, maybe it is time to focus your route to peace on anx instead google-diagnosing a physical issue. If you google you can always find a connection between your "symptoms" and a horrible illness so if you want to avoid that route then avoid googling because you already know what it will do to your anx.
What have you done over the last 6 years wrt this issue? Therapy cbt counselling self help books etc?
The doctor is my GP. I am a new patient of his which is why he did an EKG. I have had others in the past which were normal. This EKG showed early re-polarization, which is considered benign, but a few studies are suggesting it isn't which is making me worry. The anxiety itself was diagnosed way back in 2008 by a psychiatrist who I am no longer seeing. The diagnosis was generalized anxiety disorder and panic disorder. You're right I should bring my concerns to the doctor, but I have the feeling he's already getting tired and fed up.
"Any ideas on what to do or take .." I can't advise that to take especially when you have doc advising. Best to take your concerns that you read about to doc for discussion.
Also, the fact you have had what you call chronic anx does not mix well with not accepting doc's diagnosis. "The doctor insists that it's related to anxiety and that my heart is fine. " I have no way of knowing if doc is making an error, but if you can relax and accept the diagnosis in the face of these palpitations you will be on the road to peace. Is he a cardiac doc? You pluralized EKG - have you had a few docs in agreement on the diagnosis?