What is the name of the lead that measures the electrical activity from the right arm to the left arm?

The lead that measures the electrical activity from the right arm to the left arm is known as Lead I. It is one of the standard bipolar leads used in electrocardiography. In Lead I, the positive electrode is placed on the left arm while the negative electrode is on the right arm, allowing it to capture the potential difference created by the electrical impulses that propagate through the heart.

This configuration is essential as it provides a clear view of the electrical activity in the heart's horizontal plane, particularly the left atrium and left ventricle. Lead I's readings are crucial for assessing the heart's axis and identifying various cardiac conditions. Understanding the orientation of each lead is fundamental for interpreting ECG results, and Lead I plays a significant role in assessing cardiac health.