I Have The Heart Condition, S.V.T., It Doesn't Happen To

I have the heart condition, S.V.T., it doesn't happen to often, but recently it has occurred 3 times in couple of months. I have a heart monitor, that sends data to my cardiologist. Is S.V.T. a dangerous condition? Is ablation safe? I wouldn't like to go through ablation. I am on Diltiazem 240mg, and have been for few years. Thanks for your reply. Cam