ECG e-learning in video

French

Definitions

Placement of electrodes

Myocardial cells action potential

 

Welcome to this series of tutorials concerning ecg 's reading

 

- electrodes are grouped in space, in 2 planes:
              - frontal plane
              - horizontal plane

How to place the electrodes:
- in frontal plane, you place 4 electrodes
- one electrode is placed at each extremity of each limb
- the electrodes are not placed by random but each electrode has its own place, which is notified on the electrode itself by letters and by a specific international color code:
           - LA on the left arm     
           - LL on the left leg       
           - RA on the right arm  
           - RL on the right leg    
- mnemotechnic way to remember the color code: at left "the yellow sun on the green valley", at right: "the red and the black", by Stendhal

- those 4 electrodes placed in frontal plane allow to determine 6 leads:
    - 3 bipolars leads (Standard Limb Leads:):
       - D1 between RA and LA
       - D2 between RA and LL
       - D3 between LA and LL
    - 3 unipolars leads (Unipolar Limb Leads):
       - aVR between the center of the heat and RA
       - aVL between the center of the heat and LA
       - aVF between the center of the heat and LL
- at the center of heart is placed a neutral electrode (Wilson's central terminal). This electrode in fact does not exist, but is determined by electronical method. (not developped here)

 

- on the horizontal plane, you place 6 electrodes that determine 6 leads (chest leads):
             - Vl: Positioned in the 4th intercostal space just to the right of the sternum.
             - V2: Positioned in the 4th intercostal space just to the left of the sternum.
             - V3: Positioned halfway between V2 and V4.
             - V4: Positioned at the 5th intercostal space in the mid-clavicular line.
             - V5: Positioned in the anterior axillary line at the same level as V4.
             - V6: Positioned in the mid axillary line at the same level as V4 and V5.

- the chest leads are determined between the center (Wilson's central terminal) of the heart and each electrode. This means that when you record the chest leads, the limb leads have to be positioned.