I'm 17 and I have been diagnosed 2 wks ago with wpw. 4 year ago I had a borderline ecg, How did a dr not pick up on it then? Can it come and go on ecg?

WPW is a syndrome. of fainting in young adults with EKG evidence for ventricular pre excitation. If you don't faint then you don't have WPW. What you have is ventricular pre excitation. The bypass tract can be very weak and will be variable on EKG. It is easy to miss it. You have asked lots of questions about this and LBBB. You should consider a consultation so you can have a focused approach to you concerns.