Summary ECG assesment; the basics

ECG basics
Example of a normal ECG




Intervals




Large square: 200ms
Small square: 40ms, 1mm x1mm
1. Heart rate: Number of QRS complexes * 6 (Count in the rhythm strip)
Irregular: QRS complex in 30 small squares
2. Sinus rhythm
 P wave upright: Lead II
 P wave inverted: Lead aVR
 Each P wave looks the same (within the same lead)
o Check in the rhythm strip

, 3. Heart axis




Assess whether QRS complex is positive or negative:
 Always compare to the T-P segment
o The part between the T wave of the last beat and the P wave of the next beat

Heart Axis assesment
 Intermediate
o Lead I: Positive
o Lead II: Positive
 Left
o Lead I: Positive
o Lead II: Negative
 Right
o Lead I: Negative
o aVF: Positive
 Extreme
o Lead I: Negative
o aVF: Negative