Which electrode is typically used as a ground reference in an ECG?

In an electrocardiogram (ECG), the right leg electrode is typically used as a ground reference. This is crucial because it helps reduce electrical interference from external sources and stabilizes the reading by providing a common reference point.

The right leg electrode is not used for measuring cardiac signals but serves to complete the circuit. By designating it as the ground reference, it helps to ensure that the voltage readings captured from the other limbs accurately reflect the heart's electrical activity rather than picking up noise from the environment or differences in potential from other electrodes.

The other electrodes (left arm, right arm, left leg) are actively involved in capturing the electrical signals generated by the heart, thus making the right leg’s role as a ground reference vital in achieving accurate measurements. Therefore, choosing the right leg for this purpose aligns with standard ECG practices to foster optimal signal clarity.