What leads are referred to as precordial leads in a 12-lead EKG?

The precordial leads in a 12-lead EKG are specifically defined as leads V1, V2, V3, V4, V5, and V6. These leads are placed on the chest, over the heart, allowing for a direct view of the heart's electrical activity in the horizontal plane. Each precordial lead corresponds to a specific anatomic area of the heart, which assists healthcare providers in diagnosing various cardiac conditions, such as ischemia or infarction, by showing the electrical activity from different angles.

The leads V1 through V6 focus on capturing the dynamics of the heart's electrical signals specifically from the anterior and lateral aspects of the heart wall. This is crucial for accurately assessing conditions related to the ventricles and has a key role in determining the presence of any abnormalities in myocardial activity.

Other choices, such as the limb leads or the incorrectly identified leads, do not relate to the precordial area and are designed for different aspects of heart function analysis. Therefore, option B is recognized as the correct response because it directly identifies the leads that predominantly monitor the heart's activity from the precordial view.