.... I wanted to add that SVT is caused by an accessory comduction pathway for your hearts electrical system. The nature of this accessory conduction causes the sudden jump in your heart rate as opposed,to a gradual increase. It very possible that it could be some other form of tachycardia, but not SVT.
There is one unmistakable symptom of SVT aka. PSVT. It starts and stops abruptly. It doesn't slowly get faster or slowly slow down. It takes off in one beat and slows down the same way. In my untrained opinion, if your symptoms don't exhibit this behavior, you don't have SVT.