On 1st November 2014, I was cycling to work in the evening. I reached a downhill stretch and naturally stopped pedaling and allowed the bicycle to do the work. The next thing I remember, is that I was waking up on the side of the road, my bicycle a bit further down than I was. The pain I felt was unbearable, and my heart was racing at such a fast speed. I managed to call for the emergency services, and waited for the paramedic to arrive. The visit into hospital was uneventful, they controlled the pain and gave me IV fluids. The doctors had told me they believed what had happened was due to a virus and that with a few days rest, I would be right as rain. I have since seen those doctors, and they have stated they wished they hadn't said it!
Over the next (almost) 3 years, I had over 100 visits into my emergency department for the same symptoms. I am under a cardiologist, who has performed every test imaginable and opted finally for an implanted loop recorder. Over time, they have been able to fine tune things and I am now on the right medication for me, though I still get episodes of chest pain (just not with the racing heart now, which is great!). The cardiologist has given me permission to start exercising again in the past, however after the episode of SVT it triggered, he's forbidden me from doing any more.
All I can say is this:
You may not get the answer quickly. It may not be easy to treat. It may mean that after everything you're still left with a little bit of it. But it gets better!