With 12 to choose from why do we use lead II.? Watch my short explanation or read on- but please share the post . Lead II is considered the best lead for rhythm interpretation because of how the heart’s electrical activity is oriented. The main conduction pathway runs from the right atrium (SA node) down toward the left ventricle. Lead II sits diagonally across the chest, from right arm to left leg, almost perfectly aligned with this natural current. This produces clear, upright, and uniform P w