Lead III is formed by the potential difference between which electrodes?

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Multiple Choice

Lead III is formed by the potential difference between which electrodes?

Lead III measures the electrical potential difference between the left leg and the left arm, with the left leg electrode positive and the left arm electrode negative. This is one of the three standard limb leads in Einthoven’s triangle: Lead I compares the arms, Lead II links an arm to a leg, and Lead III links the other arm to a leg. So the voltage you record for Lead III is LL minus LA. The other electrode pairings correspond to the other limb leads or are not standard for Lead III.

Lead III measures the electrical potential difference between the left leg and the left arm, with the left leg electrode positive and the left arm electrode negative. This is one of the three standard limb leads in Einthoven’s triangle: Lead I compares the arms, Lead II links an arm to a leg, and Lead III links the other arm to a leg. So the voltage you record for Lead III is LL minus LA. The other electrode pairings correspond to the other limb leads or are not standard for Lead III.

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