Since only the positive electrode is polarized, these leads are considered _____ _____

Since only the positive electrode is polarized, these leads are considered _____ _____

• A. Unipolar leads
• B. Bipolar leads
• C. Central terminal leads
• D. Monitoring leads

Answer: (A)

Unipolar leads measure the heart’s electrical activity from a single positive electrode with respect to a fixed reference point. That reference, often Wilson’s central terminal, is created by averaging the potentials from the other limb electrodes. Because only the positive electrode is actively contributing to the recording, this arrangement is described as unipolar (single-ended). Bipolar leads use two active electrodes to measure a voltage difference between them, which is not the situation here. Central terminal or augmented/monitoring lead concepts relate to how the reference is formed or how monitoring is performed, but the defining feature here is the single active electrode, so these leads are unipolar leads.