A friend of mine just told me that her brother who had svt's caused by wolff-parkinson-white syndrome had an ablation which cured it and he is now in the army.
I know nothing about what heart conditions would preclude you from getting in, but I think that by all means, if a doctor has given you clearance to do so, go try to enlist. There are many brands of SVT, many are harmless, some are not. I have a little SVT myself and was told there was nothing I couldn't do and that I didn't need to take medication if I didn't want to.
So check with your doctor (hopefully a cardiologist), and if that person gives you the green light, then give it a shot.
Good luck!
I may not follow your completely, but it seems you should just go in and try to enlist.
You say you have SVT, I assume that means you have a medical doctor diagnosis, that is you have been told you have SVT by your doctor.
Give it a try.
I spent one tour in the US Navy many years ago and found the military experience very helpful in giving me a direction in my life work, electronics. There are many things one can learn in the military that are transferable to civilian life...and one can make a career out of the military too.