Which leads occupy the second column in the standard layout?

Which leads occupy the second column in the standard layout?

• A. aVR, aVL, and aVF
• B. I, II, and III
• C. V1, V2, V3
• D. V4, V5, V6

Answer: (A)

In the standard ECG layout, the frontal-plane leads are grouped together in the second column as the augmented limb leads. These leads—aVR, aVL, and aVF—are derived from the same limb electrode signals but augmented to emphasize the vectors from different parts of the heart: aVR views toward the right shoulder, aVL toward the left shoulder, and aVF from the foot. Placing them together in the second column provides a complementary set of frontal-plane perspectives to the other limb leads and helps complete the overall view of heart activity. The chest leads V1 through V6 occupy the other columns, not the second one, which is why the other groupings (standard limb leads I–III or the chest leads) don’t fit the second-column position.

In the standard ECG layout, the frontal-plane leads are grouped together in the second column as the augmented limb leads. These leads—aVR, aVL, and aVF—are derived from the same limb electrode signals but augmented to emphasize the vectors from different parts of the heart: aVR views toward the right shoulder, aVL toward the left shoulder, and aVF from the foot. Placing them together in the second column provides a complementary set of frontal-plane perspectives to the other limb leads and helps complete the overall view of heart activity. The chest leads V1 through V6 occupy the other columns, not the second one, which is why the other groupings (standard limb leads I–III or the chest leads) don’t fit the second-column position.