The basic’s of a 12 lead ECG · Limb leads 4 leads on the limbs (right and left wrists and right...

Electrical interference

Muscle tremor

Limb leads

4 leads on the limbs (right and left wrists and right

and left ankles)

Right ankle acts as ground lead-doesn’t form a trace

Need these 4 leads to have an ECG

Form Einthoven's triangle and the augmented limb

leads

Leads I, II, III, aVR, aVF and aVR

Chest leads 6 unipolar leads placed across the chest:

V1, V2, V3, V4, V5 & V6

Extra care needed with placement of the leads as incorrect placement can result in inaccurate interpretation!!

V1 4th intercostal space, right of sternum

V2 4th intercostal space, left of sternum

V3 halfway between V2 and V4 V4 5th intercostal space , midclavicular line

V5 Same horizontal position as V4, anterior axillary line V6 Same horizontal position of V4, midaxillary line.

The result..

Interpreting an ECG

1. Heart rate

2. Regularity

3. Rhythm

4. Morphology of complexes

5. Duration of complexes

6. Intervals

7. ST segments

Heart rate

We need to be able to calculate the number of QRS complexes in one minute

ECG is recorded over 10 seconds therefore you can multiply the number of

complexes on a strip by 6 to give you the rate per minute

Use the Rhythm strip at the bottom

11 complexes times 6 = 66bpm

Heart rate

Normal resting HR 60- 100 bpm

>100bpm: Tachycardia

< 60 bpm: Bradycardia