Hi ! I am a new member, but I completely understand what you are talking about. Whenever I have one of my "episodes" , I focus on my heart . The more you think its "not beating right" , the more its going to race because you have just created a bunch of adrenaline with no where for it to go. It really sounds like a panic attack, mine normally last about 15 minutes as well. Especially since it stopped on its own, without you needing to go the ER to get the medicine to stop SVT. (adenocard) (I work in a ER!!)
Have you tried taking anything when the attack starts? I take 0.5 mg of xanax and it helps me alot. you can also take a small dosage of a beta blocker, but i was on beta blockers my whole life until I had my ablation and so I really didnt want to go back on them... if its not medically necessary.
I hope you start feeling better, sometimes when I start feeling panicky, my legs get tingly and my stomach feels like its dropping like im on a rollar coaster. Then my heart starts pounding. I just take my xanax and wait for it to pass. Since you arent having longer runs of it, no chest pain, no nausea, it really sounds like it could be panic attacks. Let me know how you are doing, I'll be thinking about you!!
Oh I forgot to ask, do you have mitral valve prolapse?