EKG Memory Tools & Mean Electrical Axis

Leads I II & III

Count the "L's"
I = RA LA  = 1 L
II = RA LL = 2 Ls
III = LA LL = 3 Ls

Normal electrical axis 
Leads I & II both positive
Mean electrical axis = -30 to + 90

2nd degree Mobitz type 1 (Wenckebach) = "going, going, gone"

Why is the T wave positive if it is repolarization of the ventricles?

because the repolarization is going in the opposite direction.  A is negative charges going towards positive electrode.  B is positive charges going towards positive electrode.  C is positive charges going away from positive electrode (what happens in the ventricles).