ECG revision

Question 1

What leads look at the right ventricle?

Answer 1

Leads avR, V1, V2 and V3

Question 2

What leads look at the inferior wall of the heart?

Answer 2

avF, II and III

Question 3

What leads look at the left wall of the heart?

Answer 3

avL, I, V5 and V6

Question 4

What leads look at the anterior and septum?

Answer 4

V1-V4 (V1-2 = septum and V3-4 = anterior heart)

Question 5

How do you calculate rate?

Answer 5

• 300/No. boxes between two R waves.

- Or number of R waves in rhythm strip x 6

Question 6

T wave inversion is normal in what leads?

Answer 6

V1, V2 and III

Question 7

Where do you NOT see Q waves?

Answer 7

In V1, V2 and V3

Question 8

How will right and left axis deviation appear?

Answer 8

Right axis deviation - Lead III is most positive and lead I is negative
Left axis deviation - Lead I is most positive and leads II and III are negative
Left two the right one

Question 9

How does 1st degree heart block appear?

Answer 9

• Prolongation of PR interval (move than 5 small squares = 0.2s)

Question 10

How does 2nd degree heart block appear?

Answer 10

Morbitz type 1 - Progressive prolongation of PR interval until an eventual full block.
Morbitz type 2- Pattern of 2/3 conducted P waves followed by complete block.

Question 11

How does 3rd degree heart block appear?

Answer 11

• No electrical communication between atria and ventricles.

Question 12

What is meant by progression and what does poor progression suggest?

Answer 12

• R wave will get bigger from V1 to V6 and the S wave will get smaller from V1 to V6. Poor progression can suggest previous MI

Question 13

What does ST elevation/depression indicate?

Answer 13

ST elevation suggests infarction whereas depression indicates ischaemia.

Question 14

What are the septal ECG leads?

Answer 14

V1 and V2

Question 15

Name and describe different P wave morphologies

Answer 15

P mitrale - Bifid P waves, associated with left atrial hypertrophy.
P Pulmonale - Peaked P waves, associated with right atrial hypertrophy.
P wave inversion

Question 16

What is PEA?

Answer 16

Pulseless electrical activity. Patient is unconscious, has no central pulse but has electrical activity on the ECG.

Question 17

Describe the appearance of hyper/hypo- kalaemia

Answer 17

Push - pull effect.
Hyperkalaemia - Peaked T waves, P wave flattening and wide QRS.
Hypokalaemia - ST depression, flattened T waves, U waves and QT prolongation

Question 18

Pathological Q waves are suggestive of what?

Answer 18

A previous MI

Question 19

What is the most common cause of left bundle branch block?

Answer 19

Conduction abnormalities

Question 20

What are U waves?

Answer 20

A positive deflection between the T wave and P wave.

Question 21

What are the causes of U waves?

Answer 21

Athletes, hypokalaemia, hypercalcaemia

Question 22

What are biphasic T waves?

Answer 22

T wave with two peaks, indicates ischaemia or hypokalaemia

Question 23

Explain the appearance of SVT on the ECG

Answer 23

1. Narrow complex tachycardia, (wide if there is an underlying BBB)
2. No normal P waves
3. ST depression

Question 24

Explain the presentation of a RBBB and causes

Answer 24

rSR’ pattern in V1
Slurred S wave in V6.
Causes: RVH, PE, IHD, CHD or normal variant

Question 25

Explain the presentation of a LBBB and its causes

Answer 25

Appearance - W in V6 and M un V1
Causes - Aortic stenosis, IHD, hyperkalaemia, MI

Question 26

Explain the management of an SVT

Answer 26

Patients with adverse features (HISS) - Heart failure, ischaemia, shock or syncope should be DC cardioverted
If stable then vagal maneuvers (carotid sinus message or Valsalva maneuver) should be done first then 6mg of adenosine if failed. This will temporarily block conduction through AV node