I'm not a cardiologist (so take my comment with a pinch of salt). But I was an avid runner (running average 10km a week for 2 years) but a few years later, I developed a form of Ventricular Tachycardia called RVOT.
I went for a battery of tests similar to the OP. The results shows my heart is structurally OK. The doctor diagnosed that I had RVOT and recommended I do ablation. He says that this is a very very common procedure.
I did the procedure. However, the symptoms started coming back again.
After reading this article, I wonder if I should have just left my heart as is.