Where do you place the electrode for V1 in a 12 lead ECG?
Fourth intercostal space at the right sternal border
Where do you place the electrode for V2 in a 12 lead ECG?
Fourth intercostal space at the left sternal border
Where do you place the electrode for V3 in a 12 lead ECG?
Halfway between leads V2 and V4
Where do you place the electrode for V4 in a 12 lead ECG?
Fifth intercostal space in the midclavicular line
Where do you place the electrode for V5 in a 12 lead ECG?
Fifth intercostal space left anterior axillary
Where do you place the electrode for V6 in a 12 lead ECG?
Fifth intercostal space left midaxillary line
Which limbs do you put the limb leads on in a 12 lead ECG
- Right arm (inner wrist)
- Left arm (inner wrist)
- Left leg (inner ankle)
How wide should the QRS complex be?
< 0.10 sec / less than 3 small squares
How long should the PR interval be?
3-5 small squares / 0.12 – 0.20 sec
How long should the QT segment be?
0.35 to 0.46 seconds / 8-11 small squares
How many seconds are represented by a small box on an ECG
0.04 second
When would a QT interval be considered prolonged?
> 440ms in men or > 460ms in women
How many seconds are represented by a large box on an ECG
0.2
How do you calculate a regular heart rate?
300/number of large squares between R-R interval
How do you calculate an irregular heart rate?
Count the number of QRS complexes in 30 large squares and multiply by 10
What is the process of reading an ECG?
- Verify patient details
- Check date and time
- Check the calibration of the paper
- Is electrical activity present?
- Is the rhythm regular or irregular?
- What is the heart rate?
- P-waves present?
- What is the PR interval?
- Is each P-Wave followed by a QRS complex?
- Is the QRS duration normal?
- Look at individual leads for voltage criteria changes OR any ST or T-wave changes
What does the P wave represent?
Atrial depolarization
What does the PR interval represent?
AV node delay
What does the QRS complex represent?
Ventricular depolarization
What does the T wave represent?
Ventricular repolarization
What are the 2 types of irregular heart rhythm?
Regularly irregular and irregularly irregular
What indicates left axis deviation?
Lead I is +ve and lead II is -ve
What indicates right axis deviation?
Lead I is -ve and lead II is +ve
What indicates a normal axis?
Lead I and II are +ve
