I have SVT, my doctor recommended exercising. But my SVT isn't triggered by exercise or exertion. If you can, maybe try walking...at a low/moderate pace and see how it goes? Any exercise is better than nothing. I probably wouldn't start with strenuous exercises like Zumba (thought it is a ton of fun!) I find that I can walk for an hour and burn the same amount of calories in an hour of Zumba (depending on the instructor and intensity of their class).
Are you on any meds for the SVT?
I'm not a doctor, though. Maybe you can see another doctor and get a more decisive answer as to what is acceptable.
My thought is...the better condition my heart is in (via regular exercise and eating/drinking properly) the better it's able to tolerate a SVT episode.
I have read comments by "is_something_wrong" (user name) and it appears he is knowldegeable on all aspects of the medical concern you have and you can PM him or go to the forum.
http://www.medhelp.org/forums/Heart-Rhythm/show/92
I don't feel qualified to answer your question regarding exercise and your medical issues, and I don't have an opinion. There are other members of the forum who are experienced as well, and I am sure they can be of help. Thanks for you for your questions.
Ken