Finally V1 and V2 are considered " septal" leads because they're nearest to the interventricular septum, and V3, and V4 are " anterior" leads because they're nearest the anterior wall of the heart.

V1和V2导联为“隔导联”，因为它们最接近心脏的室间隔；V3和V4导联为“前壁导联”，因为它们最接近心脏的前壁。