Which lead records electrical activity from the left arm to the left leg?

Which lead records electrical activity from the left arm to the left leg?

• A. Lead I
• B. Lead II
• C. Lead III
• D. V1

Answer: (C)

The correct choice represents a lead that captures the electrical activity primarily between the left arm and the left leg. In the context of the electrocardiogram (ECG), Lead II specifically measures the difference in electrical potential between these two points (the left arm to the left leg), thus allowing for the assessment of the heart's electrical activity in a direction that is typically aligned along the body’s natural electrical pathways. This lead is especially useful for evaluating the overall rhythm of the heart and identifying various cardiac conditions. In contrast, other leads such as Lead I monitor activity between the right arm and the left arm, focusing on the horizontal plane, while Lead III measures the potential between the left leg and the left arm. V1, being a precordial lead located on the right side of the chest, primarily assesses the electrical activity in the area near the heart rather than across the limbs. Therefore, Lead II most accurately captures the electrical signal traveling from the left arm to the left leg.

The correct choice represents a lead that captures the electrical activity primarily between the left arm and the left leg. In the context of the electrocardiogram (ECG), Lead II specifically measures the difference in electrical potential between these two points (the left arm to the left leg), thus allowing for the assessment of the heart's electrical activity in a direction that is typically aligned along the body’s natural electrical pathways. This lead is especially useful for evaluating the overall rhythm of the heart and identifying various cardiac conditions.

In contrast, other leads such as Lead I monitor activity between the right arm and the left arm, focusing on the horizontal plane, while Lead III measures the potential between the left leg and the left arm. V1, being a precordial lead located on the right side of the chest, primarily assesses the electrical activity in the area near the heart rather than across the limbs. Therefore, Lead II most accurately captures the electrical signal traveling from the left arm to the left leg.