ECG Workshop

Question 1

Where do you place the electrode for V1 in a 12 lead ECG?

Answer 1

Fourth intercostal space at the right sternal border

Question 2

Where do you place the electrode for V2 in a 12 lead ECG?

Answer 2

Fourth intercostal space at the left sternal border

Question 3

Where do you place the electrode for V3 in a 12 lead ECG?

Answer 3

Halfway between leads V2 and V4

Question 4

Where do you place the electrode for V4 in a 12 lead ECG?

Answer 4

Fifth intercostal space in the midclavicular line

Question 5

Where do you place the electrode for V5 in a 12 lead ECG?

Answer 5

Fifth intercostal space left anterior axillary

Question 6

Where do you place the electrode for V6 in a 12 lead ECG?

Answer 6

Fifth intercostal space left midaxillary line

Question 7

Which limbs do you put the limb leads on in a 12 lead ECG

Answer 7

• Right arm (inner wrist)
• Left arm (inner wrist)
• Left leg (inner ankle)

Question 8

How wide should the QRS complex be?

Answer 8

< 0.10 sec / less than 3 small squares

Question 9

How long should the PR interval be?

Answer 9

3-5 small squares / 0.12 – 0.20 sec

Question 10

How long should the QT segment be?

Answer 10

0.35 to 0.46 seconds / 8-11 small squares

Question 11

How many seconds are represented by a small box on an ECG

Answer 11

0.04 second

Question 12

When would a QT interval be considered prolonged?

Answer 12

> 440ms in men or > 460ms in women

Question 13

How many seconds are represented by a large box on an ECG

Answer 13

0.2

Question 14

How do you calculate a regular heart rate?

Answer 14

300/number of large squares between R-R interval

Question 15

How do you calculate an irregular heart rate?

Answer 15

Count the number of QRS complexes in 30 large squares and multiply by 10

Question 16

What is the process of reading an ECG?

Answer 16

• 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

Question 17

What does the P wave represent?

Answer 17

Atrial depolarization

Question 18

What does the PR interval represent?

Answer 18

AV node delay

Question 19

What does the QRS complex represent?

Answer 19

Ventricular depolarization

Question 20

What does the T wave represent?

Answer 20

Ventricular repolarization

Question 21

What are the 2 types of irregular heart rhythm?

Answer 21

Regularly irregular and irregularly irregular

Question 22

What indicates left axis deviation?

Answer 22

Lead I is +ve and lead II is -ve

Question 23

What indicates right axis deviation?

Answer 23

Lead I is -ve and lead II is +ve

Question 24

What indicates a normal axis?

Answer 24

Lead I and II are +ve

Question 25

What commonly causes left axis deviation?

Answer 25

Heart conduction defects eg left anterior fascicular block and inferior MI

Question 26

What commonly causes right axis deviation?

Answer 26

Right ventricular hypertrophy

Question 27

What does a saw tooth baseline indicate?

Answer 27

Atrial flutter

Question 28

What does a broad QRS with a delta wave indicate?

Answer 28

Wolff-Parkinson-White syndrome

Question 29

What do tall tented T waves indicate?

Answer 29

Hyperkalaemia

Question 30

What does absent P waves indicate?

Answer 30

AF

Question 31

What can cause a prolonged PR interval?

Answer 31

AV block (heart block)

Question 32

What ECG changes do you see in first degree heart block

Answer 32

A fixed prolonged PR interval

Question 33

What ECG changes do you see in second degree heart block (Mobitz type 1)

Answer 33

The PR interval slowly increases then there is a dropped QRS complex

Question 34

What ECG changes do you see in second degree heart block (Mobitz type 2)

Answer 34

The PR interval is fixed but there are dropped beats

Question 35

What ECG changes do you see in third degree heart block

Answer 35

The P waves and QRS complexes are completely unrelated

Question 36

What does a delta wave look like?

Answer 36

Slurred upstroke on the QRS complex