Which type of electrocardiograph leads are unipolar leads that record the electrical activity of the heart in the horizontal plane?

The precordial leads are correctly identified as unipolar leads that assess the heart's electrical activity in the horizontal plane. These leads are placed on the chest and focus on providing a view of the heart's electrical activity from a horizontal perspective, which is essential for detecting various cardiac conditions.

The precordial leads—V1, V2, V3, V4, V5, and V6—each provide unique information based on their specific placement over different areas of the heart. Because they are unipolar, they measure the potential difference between the positive electrode placed at the chest location and a central reference point formed by the average of the limb leads. This configuration is important for identifying issues such as wall motion abnormalities or other localized problems within the heart.

In contrast, augmented limb leads and standard limb leads involve different configurations and do not provide a horizontal plane view. Augmented limb leads (aVR, aVL, aVF) provide additional perspectives by combining input from limb leads in a way that enhances diagnostic capability, while standard limb leads (I, II, III) are bipolar and focus on electrical activity in the frontal plane. Thus, precordial leads are distinct in their unipolar nature and horizontal plane orientation,