Which electrode is typically used as the ground in a standard ECG?

Which electrode is typically used as the ground in a standard ECG?

• A. Right leg (RL)
• B. Left leg (LL)
• C. Right arm (RA)
• D. Left arm (LA)

Answer: (A)

Grounding in an ECG provides a stable reference point and helps suppress electrical noise, especially mains interference. In a standard setup, the electrode placed on the right leg serves this ground role. The limb leads—coming from the right arm, left arm, and left leg—are used to record the heart’s activity, while the right leg acts as a reference and sink for stray currents. Some systems even actively drive the right-leg electrode with a counter-signal to further reduce noise. That’s why the right leg electrode is typically used as the ground.

Grounding in an ECG provides a stable reference point and helps suppress electrical noise, especially mains interference. In a standard setup, the electrode placed on the right leg serves this ground role. The limb leads—coming from the right arm, left arm, and left leg—are used to record the heart’s activity, while the right leg acts as a reference and sink for stray currents. Some systems even actively drive the right-leg electrode with a counter-signal to further reduce noise. That’s why the right leg electrode is typically used as the ground.