D.B.
ETA: Thanks for your PM that there was a human error in the test itself! Glad it's resolved!
Original answer: There can be all kinds of reasons. My doctor scared the bejeezus out of me and thought I had had a "silent heart attack" - I got sent to a cardiologist and she repeated the test plus a stress test, and said the original problem was the result of a faulty lead on the original EKG. So it's really good not to panic about anything!
Try not to use Dr. Google too much - it can throw you off and make you worry for nothing. If there's anything questionable, my advice is to get a 2nd opinion and a 2nd test on another piece of equipment with a different doctor reading it.
Good luck!