The next step up from a 3 Lead ECG is the 5 Lead ECG. The 5 lead ECG adds two more electrodes to the 3 Lead setup, one deemed Right Lower/Leg (RL) and “V”.
RL
The RL electrode, often referred to a “common” or “ground” electrode, is an integral part of the 5 lead and 12 lead ECG’s. This electrode acts as a ground to the electrical system. While RU, LU, and LL all provide different views of the electrical impulse, by acting as a ground the RL lead dampens the amount of noise within the signal providing a clearer ECG strip tracing.
Noise
**A note about “noise.” When we examine an ECG strip there may be awkward or weird fluctuations within the signal that do not look like any of the standard wave forms depicted in a standard ECG strip. This noise caused the picking up other electrical signals within the body or even body movements. The goal of the RL lead is to dampen an noise created by other electrical signals within the body. The RL lead does not work well dampening noise caused by movement.**
V
The V electrode placement is within the 4th intercostal space along the right sternal border. When we get to examining electrode placement for the 12 Lead ECG this will be the location of V1.
V is our only new view from what was covered in the 3 lead course. Rather than posting a video here to explain this strip, a question will be posed for your consideration.
Question
The ECG strip above shows a normal V tracing. Why do you think the QRS deflection is mostly negative?
Use the image below to answer the question posted.
If you are unsure about the answer please reference the ECG Impulse Basics and the 3 Lead ECG articles.
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