Which lead is formed between the right arm and left leg, with the right arm as the negative electrode and the left leg as the positive electrode?

Which lead is formed between the right arm and left leg, with the right arm as the negative electrode and the left leg as the positive electrode?

• A. Lead II
• B. Lead I
• C. Lead III
• D. aVR

Answer: (A)

Einthoven limb leads define the orientation of the ECG recording on the frontal plane as measurements between pairs of limb electrodes. The lead formed between the right arm and the left leg, with the right arm as the negative electrode and the left leg as the positive electrode, is Lead II. In this setup the electrical vector points from RA toward LL, typically producing a downward and leftward deflection that is commonly used for rhythm assessment because it often captures the heart’s activity aligned with its mean electrical axis. The other standard bipolar leads are between the right arm and left arm (Lead I) and between the left arm and left leg (Lead III). An augmented lead like aVR is not a simple right-arm-to-left-leg measurement; it uses the right arm as a reference with an averaged opposite impedance from the other two limbs.

Einthoven limb leads define the orientation of the ECG recording on the frontal plane as measurements between pairs of limb electrodes. The lead formed between the right arm and the left leg, with the right arm as the negative electrode and the left leg as the positive electrode, is Lead II. In this setup the electrical vector points from RA toward LL, typically producing a downward and leftward deflection that is commonly used for rhythm assessment because it often captures the heart’s activity aligned with its mean electrical axis. The other standard bipolar leads are between the right arm and left arm (Lead I) and between the left arm and left leg (Lead III). An augmented lead like aVR is not a simple right-arm-to-left-leg measurement; it uses the right arm as a reference with an averaged opposite impedance from the other two limbs.