Tuesday, September 8, 2009


What is ECG?

When impulses passes through heart the electrical current also spreads to the surrounding tissue and to surface of body.When electrodes are placed on the surface then it can record the electrical activity.This is known as ECG

ECG Paper:
ECG Paper: contains small and large squares.

Each small squares is 1mm and large square is 5mm

Time is measured along horizontal line and each small square is 0.04s and each large square is 0.2s.

Voltage is measured along vertical line and 10mm is equal to 1mV.

ECG paper moves at 25mm/s speed i.e. 1500sq/min

ECG leads
3 types of leads:


1.Chest leads/precordial leads:V1,V2,V3,V4,V5, and V6.


2.Bipolar leads/standard/Einthoven's Leads: I II III.

3.Augmented Unipolar leads: aVR, aVL ,aVF.


Augmented Leads:

aVR: Right arm

aVL: Left arm

aVF: Left foot

Chest leads:

V1: in 4th ICS at right sternal border .

V2:in 4th ICS at left sternal border .

V3:Mid way between V2 and V3

V4:5th ICS in left MCL (mid clavical line)

V5:Anterior axillary line in 5th ICS

V6:Mid axillary line in 5th ICS .....


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