ECG leads: The Dirty ECG leads: The Dirty DozenDozen

Conventionally,

12 leads or sets of electrodes

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20132013

ECG leads: The ECG leads: The DirtyDirty Dozen Dozen

DirectionPolarity

Why do I need to know these details ??

Because the Because the DirtyDirty Dozen Dozen

DirectionPolarity

1. determine deflections of the ECG2. detect direction of depolarization

wave Deviation of cardiac axis3. detect (or localize) the diseased or

disordered part of the heart

Hi, I’m EasyG. I’ll show you to work out the

ofof

Dirty Dirty

half-Dozenhalf-Dozen

Direction &Polarity

the 6 limb leads in the frontal plane

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

Where shall we start forming a triangle? The top, of course,

since we always read from top downwards

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

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

The 1st move, the top border of a triangle

so its Lead IThe fist always is the

(+)ve electrode

The shoulder the (-)ve electrode

The 2nd move, swing your arm down to form the 2nd border

… its Lead II

Now it’s the left arm’s job to make a 3rd move and close the triangle

… its Lead III

Raise the right fist like this

… its aVR

Raise the left fist like this, it’s…

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

Once more!!!

Action!

I

II

III

aVR

aVL

aVF

Lead I

aVL

Lead III Lead II

aVR

aVF

Got it?Thanks !!!