When monitoring a heart with lead II, how are the leads polarized?

When monitoring a heart with lead II, the correct configuration involves placing the positive electrode on the left leg and the negative electrode on the right arm. This setup allows for the most effective depiction of the electrical activity of the heart as it generates a vector directed from the right arm toward the left leg, which is where lead II is positioned.

The choice of having the left leg as the positive lead enables the detection of the depolarization wavefront as it moves downward towards the left leg, reflecting the natural pathway of electrical conduction through the heart. Additionally, positioning the right arm as the negative lead helps to establish a reference point in this lead configuration, which allows for the accurate reading of heart rhythm and the analysis of electrical impulses.

This orientation is ideal for capturing the overall rhythm of the heart, essential for diagnosing conditions such as arrhythmias or other cardiac abnormalities. The other configurations would not align with the standard representation of lead II, which could lead to inaccuracies in monitoring the heart's activity.