# ECG interpretation

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• Created by: z
• Created on: 04-03-16 18:31

## 10 steps of evaluating an ECG

1.       Patient demographics

2.       Rate

3.       Rhythm

4.       Axis

5.       P wave

6.       PR interval

7.       QRS complex

8.       ST segment

9.       T wave

10.   QT interval

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## Rate and rhythm

• Rate
• Normal is 60-100bpm
•  Workout as 300/(large squares b/w QRS complex)
• Rhythm
• Regular/irregular?
•  Use piece of paper to compare distance b/w R-R intervals
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## Axis

• Normal is between -30o and +90o
•  < -30o = left axis deviation
•   > +90o = right angle deviation
•  Between 180o and -90o = far RAD or far LAD (“Northwest”)
•  Identifying the axis:
• Identify most isoelectric lead (i.e. w/ flattest QRS)
• Axis is at 90o to this
• If deflection is positive
• NB quick method – if I and II are positive= normal
• If “reaching” towards = RAD
• If “leaning” away = LA
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## Parts of the ECG

• P wave
• P wave = atrial depolarisation
• PR interval
• PR interval = AV delay
• Normal = 0.12-0.2s
• QRS
• QRS complex = ventricular depolarisation (down BoH then up PF)
• Normal <0.12s
• ST segment
• Time b/w end of depol and start of repol
• Should be isoelectric
• T wave
• Ventricular repolarisation
• Normal to be inverted in aVR, V1, sometimes V2
• QT interval
• From beginning of QRS to end of T wave
• Normal is 0.38-0.42s
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