Which leads provide information about the heart's frontal plane?

The limb leads provide critical information about the heart's frontal plane. This is because the limb leads (I, II, III, aVL, aVR, aVF) are oriented in a way that allows them to capture electrical activity as it moves vertically through the heart, thus enabling the assessment of the frontal plane’s electrical activity. This plane includes movements of the electrical impulse in the anterior-posterior and left-right directions.

In contrast, the precordial leads focus on the heart's horizontal plane and are placed across the chest, which helps to visualize the electrical activity in a different orientation. Augmented leads enhance the signals from the standard limb leads but do not independently provide frontal plane information in the same way as the limb leads. Chest leads are more concerned with the posterior and lateral aspects of the heart, rather than providing a view into the frontal plane. Therefore, the selection of the limb leads reflects their specific role in delineating the electrical characteristics of the heart from a frontal perspective.