| 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.
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