If it has been a number of years since your last echo you can ask for a new one just to be sure things haven't changed. How is your blood pressure and what is your heart rate on a normal basis? Have you had your stomach checked? Do you lift heavy equipment like oxygen tanks for your job? If you do heavy lifting you may want to have your back checked out to make sure there isn't some misalignment causing a pinched nerve or something. In any event, when it comes to doctors I have found that you do sometimes have to be pretty persistent to get to an answer. Just keep going back with your complaints and ask what other avenues can you pursue to decipher where the pain is coming from. Obviously if OTC pain meds are not helping the pain then something is going on that needs addressing. It may not be the heart but obviously it is something. Well I do wish you luck sorting it out. I know how frustrating it can be to be sick and not be able to find the source.
I only get very short runs consisting of maybe 6 or 7 beats and this happens very infrequently. I usually stop what I am doing until it passes. I have been on atenolol for about the last 10 years for the palpitations. What puzzles me is the heaviness in my chest that I feel. I don't really feel short of breath but more of a pressure. My echo was several years ago. I am a respiratory therapist and can't think of anything that would cause me this type if pain. I have dealing with this for awhile now and it just seems to be getting worse. I don't like to take different meds and have only tried aleve and Motrin for the pain. They don't seem to help. I had an ultrasound of my gall bladder and that to was normal. If everything is coming back normal than why am I still miserable?
I would suspect unless you have some sort of genetic health problem like marfan syndrome it is not likely you would have an aortic dissection especially if you had a clean echo. It is possible the svt is partly the cause. How often do you get the runs? Do you go about your normally when you get them or do you stop and wait till they pass? Also, what do you do for a living? I actually use to play darts and did not realize that with my small size, I'm only 5'1" I was using too much force to throw the dart to get it to the board and was unwittingly over exerting the muscles on the right side causing it to pull my spine out of line. It caused all sorts of upper back problems so just look at your physical activity and see if there is actually something that could be causing unbalanced stress on the muscles of the back. As for the svt, how long are the episodes and how often? Were you offered an ablation to correct the issue for good?
Do you take a statin? Also, pain in this area can be referent (called "referred pain"), meaning it's coming from some place else. quite often, GI pressure or pain can be felt radiating in the chest, back, left arm, and up through the neck area.