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: 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
3 types of leads:
(HORIZONTAL PLANE LEADS)
1.Chest leads/precordial leads:V1,V2,V3,V4,V5, and V6.
(FRONTAL PLANE LEADS)
2.Bipolar leads/standard/Einthoven's Leads: I II III.
3.Augmented Unipolar leads: aVR, aVL ,aVF.
PLACEMENT OF LEADS
aVR: Right arm
aVL: Left arm
aVF: Left foot
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 .....