What is supraventricular ectopy? Is it benign? Is this the same as sinus tachycardia?

No. . Supra ventricular ectopy is electrical activity not originating at the sa node. Depending on how often and the number of ectopic sites will determine if it is benign or not. Sinus tach is a rapid hr, generally >100 <150, but the electrical impulse follow the normal pathway of sa node --> av node --> bundle oh hiss. Just faster than normal (60 -100 bpm).