I had a different type of tachycardia... I was diagnosed with AVNRT (atrioventricular nodal reentry tachycardia). It sucked! And it sort of caused the syncope. It sucked!! I ended up having a minor surgery on the heart to try to assist with the tachycardia. It worked wonders. I havent had the rapid heart rates, and I have not fainted in years!