The V leads from the 47 year old female whose frontal plane leads were shown on an earlier pages (2.1.1-2.1.6) are ahown here. They demonstrate the biphasic morphology of the P waves in leads V1 and V2. Note that in these leads, the initial portion of the P wave is positive, or upright, reflecting the anteriorly directed vector associated with right atrial depolarization. This is followed by the negative, or inverted portion of the P wave, which reflects depolarization of the left atrium. The P waves in leads V3 to V6 then become progressively more positive, reflecting the overall leftward and posteriorly directed spread of atrial depolarization.