For a 3-electrode ECG, the electrodes are typically placed in the following locations:
– Right arm (RA) – place the electrode on the right wrist or forearm. This will serve as the negative electrode.
– Left arm (LA) – place the electrode on the left wrist or forearm. This will serve as the positive electrode.
– Ground (GND) – place the ground electrode on the right leg, usually above the ankle. This serves as the reference point.
The 3-electrode setup records the electrical activity between the right and left arms. This configuration is referred to as a bipolar limb lead or Lead I. It provides a view of the heart’s electrical conduction from the perspective of the axis between the two arms. The ground electrode helps reduce interference and noise in the signal. Proper skin preparation and the use of conductive gel or paste are important when placing the ECG electrodes to get good signal quality. The arms should be abducted slightly away from the body. Keep the wires secured to minimize motion artifacts.
