Septal precordials: V1–V2

The precordial leads view the horizontal plane. V1–V2 sit over the right ventricle and septum, so they see the main (leftward) depolarization moving away: a small r then a deep S.

• V1–V2: an rS complex, small initial r (septal), then a deep S as LV forces move away.
• The T wave in V1 may be flat or slightly inverted, a normal variant.
• This is where precordial R-wave progression begins.