Interpretation

Question 1

In what leads do you look at in order to determine the electrical axis of the heart?

Answer 1

Leads I, II , aVF

Question 2

What leads look at the LATERAL view of the heart and what vascular territory does it correspond to?

Answer 2

Leads I, aVL, V5, V6

Left Circumflex Artery

Question 3

What leads look at the INFERIOR view of the heart and what vascular territory does it correspond to?

Answer 3

Leads II, II, aVF

90% RCA, 10% LCx

Question 4

What leads look at the SEPTAL view of the heart and what vascular territory does it correspond to?

Answer 4

Leads V1, V2

Proximal Left Anterior Descending

Question 5

What leads look at the ANTERIOR view of the heart and what vascular territory does it correspond to?

Answer 5

Leads V3 - V4

Left Anterior Descending

Question 6

What ECG changes do you expect to find with hyperkalaemia?

Answer 6

Short P-waves
Prolonged PR interval
Wide QRS complex
Tented T-waves

Question 7

List some causes of Left Axis Deviation on an ECG.

Answer 7

Left Bundle Branch Block
Left Anterior Fasicular Hemiblock
Congenital Heart Disease
Left Ventricular Hypertrophy
Mechanical Shift
Physiological (eg. short stature, obesity)

Question 8

List some causes of Right Axis Deviation on an ECG.

Answer 8

Right Bundle Branch Block
Pulmonary Hypertension
Massive PE
Dextrocardia
Mechanical Shift
Right Ventricular Hypertrophy
Physiological (eg. Age, Physical Activity, Obesity, Diabetes, HTN)

Question 9

What are some ECG changes you would expect in a massive PE?

Answer 9

Deep S-wave in Lead I
Q-wave in Lead III
T-wave inversion in Lead III

Question 10

What heart block is associated with a prolonged PR interval?

Answer 10

First degree heart block

Question 11

What heart block is associated with an elongating PR interval with dropped QRS waves?

Answer 11

Second degree heart block (Mobitz I)

Question 12

What heart block is associated with a fixed ratio of P:QRS waves of 2:1 or 3:1 or 4:1?

Answer 12

Second degree heart block (Mobitz II)

Question 13

What heart block is associated with no association between P & QRS waves?

Answer 13

Third degree (complete) heart block

Question 14

List some causes of 1st degree heart block & 2nd Degree (Mobitz I) heart block

Answer 14

Physiological: Normal variant, athletes, increased vagal tone
Pathological: Inferior MI, Hypokalaemia, Myocarditis
Iatrogenic: Mitral Valve surgery, Drugs (eg. amiodarone, b-blockers, CCBs)

Question 15

List some causes of 2nd Degree (Mobitz II) & complete block

Answer 15

SLE
Systemic Sclerosis
Anterior MI
Hyperkalaemia
Idiopathic Fibrosis of Conductive System

Question 16

Why is Complete Heart Block a worrying sign & what needs to be done about it?

Answer 16

Haemodynamically unstable
Risk of syncope & sudden death

Management:

• Urgent admission
• Temporary pacing -> Permanent pacemaker
• Cardiac monitoring

Question 17

What criteria on an ECG would make you suspect a POSTERIOR MI/lesion?

Answer 17

• No direct lead orientation

- Inverse/Mirror changes present

Question 18

What are the characteristic ECG changes associated with a PE?

Answer 18

S1Q3T3

• Deep S wave in Lead I
• Deep Q wave in Lead III
• T-wave inversion in Lead III

Signs of RBBB (M-V1 and W-V6)