The lead that records the heart’s voltage difference between the left leg electrode and a central point between the right arm and left arm is called which?

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This question tests how augmented limb leads are defined in an ECG and what the Wilson central terminal represents. The Wilson central terminal is a reference point created by averaging the voltages from the three limb electrodes. Augmented limb leads keep one limb as the positive electrode and measure the voltage difference between that limb and the Wilson central terminal, which magnifies the signal.

For the described scenario, the left leg is the positive electrode while the reference is the central point formed by the other two arms. That is why this lead records the heart’s voltage difference between the left leg and the central terminal between the right arm and left arm. The other standard pairings involve different limb-to-arm placements and don’t use the Wilson central terminal as the reference, so they describe other directional views rather than the left leg to the central terminal.