This document discusses the 12 standard electrocardiogram (ECG) leads used to monitor the heart from different electrical perspectives. It explains that the "Dirty Dozen" leads determine the direction and polarity of the depolarization wave, which can detect diseased parts of the heart. The second half focuses on forming a triangle with the arms and legs to represent the spatial positions of the 6 limb leads (Leads I, II, III, aVR, aVL, aVF) in the frontal plane.

1. ECG leads: The DirtyECG leads: The Dirty DozenDozen
Conventionally,
12 leads or sets
of electrodes
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20132013

2. ECG leads: TheECG leads: The DirtyDirtyDozenDozen
Direction
Polarity
Why do I need
to know these
details ??

3. Because theBecause the DirtyDirtyDozenDozen
Direction
Polarity
1. determine deflections of the ECG
2. detect direction of depolarization
wave Deviation of cardiac axis
3. detect (or localize) the diseased or
disordered part of the heart

4. Hi, I’m EasyG. I’ll show
you to work out the
ofof
DirtyDirty
half-Dozenhalf-Dozen
Direction &
Polarity
the 6 limb leads
in the frontal plane

5. the 6 limb leads in the frontal plane
Lead I
aVL
Lead III Lead II
aVR
aVF
monitoring the heart
from different
electrical
perspectives
It’s not fair to label us the
dirty half-dozen
The other half-dozen are on
the chest – the 6 chest leads

6. Where shall we start
forming a triangle?
The top, of course,
since we always
read from top
downwards

7. Which arm shall we
move first ? Ah!! The
right arm!! as most of
us are right-handed

8. So, make a fist.
And make your 1st
move.
Swing up your arm.

9. The 1st move, the
top border of a
triangle
so its Lead I
The fist always is the
(+)ve electrode
The shoulder the
(-)ve electrode

10. The 2nd move,
swing your arm
down to form the
2nd
border
… its Lead II

11. Now it’s the left
arm’s job to make a
3rd
move and close
the triangle
… its Lead III

12. Raise the right fist
like this
… its aVR

13. Raise the left fist
like this, it’s…

14. Stomp the
ground with your
left foot,
it’s…

15. Once more!!!
Action!

16. I

18. II

21. III

23. aVR

25. aVL

26. aVF

28. Lead I
aVL
Lead III Lead II
aVR
aVF
Got it?
Thanks !!!