ECG

Question 1

6 chest electrodes in a 12-lead ECG

Answer 1

V1-V6
Red, yellow, green, brown, black, purple

Question 2

4 limb electrodes in a 12-lead ECG

Answer 2

RA, LA, LL, RL
Red, yellow, green, black

Question 3

Location of limb electrodes on 12-lead ECG

Answer 3

• Ulnar styloid process (wrist)
• Medial or lateral malleolus (ankle)

Question 4

3-Lead electrode placement

Answer 4

RA, LA, LL
Red, yellow, green

Question 5

5-Lead ECG electrode placement

Answer 5

RA, LA, LL, V, RL
Red, yellow, green, white, black

Question 6

What is the importance of ECG paper?

Answer 6

• Easy measurement of cardiac timing intervals - any timing irregularities can be seen.
• Can work out heart rate just by looking at the ECG trace.

Question 7

What causes supraventricular tachycardia (SVT)?

Answer 7

Increased rate of depolarisation

Question 8

What are the two shockable rhythms?

Answer 8

Pulseless ventricular tachycardia (pVT) and ventricular fibrillation (VF)

Question 9

What happens during the PR interval?

Answer 9

Electrical impulse spreads over atrium, through AV node and Bundle of His

Question 10

What happens during the ST segment?

Answer 10

Isoelectric point - no change in electrical activity

Question 11

What happens during the QT interval?

Answer 11

Depolarisation and repolarisation of the ventricles

Question 12

What happens during the P wave?

Answer 12

• Spread of electrical impulse across atria from SA node
• Atrial depolarisation

Question 13

What happens during the QRS complex?

Answer 13

• Spread of electrical impulse through the ventricles
• Ventricular depolarisation

Question 14

What happens during the T wave?

Answer 14

Ventricular repolarisation

Question 15

What causes sinus tachycardia?

Answer 15

Increased rate of depolarisation in the SA node

Question 16

What is the pattern of the PQRST complex in sinus tachycardia?

Answer 16

Normal

Question 17

What is the pattern of the PQRST complex in ventricular tachycardia?

Answer 17

Absent P waves and a wide QRS complex
(Very plain up and down)

Question 18

What causes supraventricular tachycardia?

Answer 18

Increased rate of depolarisation

Question 19

How is supraventricular tachycardia characterised on ECG?

Answer 19

Absent or abnormal P waves

Question 20

What causes atrial fibrillation?

Answer 20

Electrical impulses fire off from different places in the atria, in a disorganised way

Question 21

How is atrial fibrillation characterised on ECG?

Answer 21

Irregular rhythm with no P waves

Question 22

What causes ventricular fibrillation?

Answer 22

The ventricles suddenly attempt to contract at rates of up to 500bpm

Question 23

Which arrhythmia shows the heart is no longer an effective pump and advanced life support is needed?

Answer 23

Ventricular fibrillation

Question 24

How is ventricular fibrillation characterised on ECG?

Answer 24

Chaotic irregular deflections of varying amplitude with no identifiable P waves, QRS complexes, or T waves

Question 25

What is pulseless electrical activity?

Answer 25

Electrical activity of heart appears normal on ECG BUT it is not accompanied by the mechanical function of the heart, and no pulse is present

Question 26

What are the 6 T’s?

Answer 26

- Thrombosis (pulmonary or coronary) - Tension pneumothorax - Cardiac tamponade - Toxins (e.g. drug overdose) - Tachycardia - Trauma

Question 27

What are the 6 H’s?

Answer 27

- Hypovolaemia - Hyper/Hypokalaemia - Hypoxia - Hydrogen ions (Acidosis) - Hypothermia - Hypoglycaemia

Question 28

The 6 H's and T's are potential causes of which arrhythmias?

Answer 28

Pulseless electrical activity and asystole

Question 29

What is the treatment for PEA and asystole?

Answer 29

- Emergency CPR - Urgent adrenaline administration - Treat the underlying cause (6H’s and 6T’s)