For avnrt and avrt (the latter also called wolf parkinson white) the success rate can be as high as 98%.
The same can also be true for typical (right atrial) atrial flutter
. Atrial tachycardias in expert hands can be as successful as 85%, even if of a complicated type. Ventricular tachycardias are a much more diverse group, and more info would be needed to give a good answer.