I’m 41. Been having SVT’s for 13 years roughly and my cardiologist says my heart is in great shape (no blockage, no irregular beats, nothing. I think it’s anxiety. Either way I just know one of these times my heart gets up to 200bpm and holds there that’s going to be it. It’s frustrating to have all these tests ran just to be told that they don’t know what’s going on and good luck.