Have you had a workup by a card-carrying infectious disease specialist? Given your history, I think that should be Step One.
Hi. No similar experience here and yes, it is a long story, but it is definitely a page turner...
Bottom line here. This is kind of an unusual one, especially for the heart rhythm board. I would go back to the doctor again, or, do you have access to a high quality medical system such as Mayo, and decent medical insurance? Either way, it sounds like you could use some professional medical help with this (i.e. you might need to work on keeping your doctor focused, or go see a more experienced team).
I wish there is something else I knew or could say to help. I think you are doing the right thing. Its prudent to seek answers to this. You need to let doctors do their magic. But someone needs to recognize when a problem is more complex than small scale medical teams are able to handle. Its a bit of a judgement call, but I sense that your current medical team is missing something.
Here is some information about these conditions:
http://www.myocarditisfoundation.org/about-myocarditis/
http://emedicine.medscape.com/article/156330-workup
http://www.mayoclinic.org/diseases-conditions/endocarditis/basics/symptoms/con-20022403
"The most common symptom of myocarditis is shortness of breath during exercise or exertion. This symptom usually develops 7 to 14 days...Other symptoms may include fatigue, heart palpitations and chest pain or pressure. The legs also may swell. Rarely, myocarditis causes a sudden loss of consciousness that may be due to abnormal heart rhythms. In summary, patients may experience some, all or none of the following symptoms: shortness of breath, chest pain, lightheadedness, irregular heartbeat, sudden loss of consciousness."
"Endocarditis may develop slowly or suddenly — depending on what's causing the infection and whether you have any underlying heart problems. Endocarditis signs and symptoms vary, but may include:
Fever and chills
A new or changed heart murmur — heart sounds made by blood rushing through your heart
Fatigue
Aching joints and muscles
Night sweats
Shortness of breath
Paleness
Persistent cough
Swelling in your feet, legs or abdomen
Unexplained weight loss
Blood in your urine (either visible or found in a doctor's viewing of your urine under a microscope)
Tenderness in your spleen — an infection-fighting abdominal organ on your left side, just below your rib cage
Osler's nodes — red, tender spots under the skin of your fingers
Petechiae (puh-TEE-key-ee) — tiny purple or red spots on the skin, whites of your eyes or inside your mouth"