Lecture 2: ECG

Question 1

In which body position do you perform an ECG?

Answer 1

Right lateral

Question 2

Lead I is between:

Answer 2

RF and LF

Question 3

Lead II is between:

Answer 3

RF and LH

Question 4

Lead III is between?

Answer 4

LF and LH

Question 5

What angle is lead I?

Answer 5

0

Question 6

What angle is lead II?

Answer 6

60

Question 7

What angle is lead III?

Answer 7

120

Question 8

Which specialised conduction fibres are in the atria?

Answer 8

None

Question 9

What determines if a wave is +ve or -ve?

Answer 9

Whether it is moving towards or away from the +ve electrode

Question 10

What can the wave look like if it is perpendicular to the +ve electrode?

Answer 10

Biphasic

Question 11

What can you NOT diagnose from an ECG?

Answer 11

Heart failure

Question 12

In which species can and ECG indicate chamber enlargement?

Answer 12

Dogs and cats

Question 13

Which five other abnormalities can be diagnosed with an ECG?

Answer 13

Electrolyte abnormalities, myocardial ischaemia/hypoxia, drug intoxication (esp digoxin), pleural/pericardial effusion, hypothyroidism

Question 14

What are 5 causes of a QRS arising without a P?

Answer 14

Ventricular depolarisation, junctional depolarisation, atrial standstill, atrial fibrillation, sinus arrest with escape complexes

Question 15

Which node controls a sinus rhythm?

Answer 15

SA

Question 16

What are three characteristics of a sinus rhytm?

Answer 16

P for every QRS, PR interval constant, P wave is positive in lead II

Question 17

In which species in sinus arrhythmia normal?

Answer 17

Dogs

Question 18

What causes sinus arrhythmia?

Answer 18

Vagal tone

Question 19

Why is sinus arrhythmia abolished under anaesthetic?

Answer 19

Adrenergic tone and haemodynamic changes

Question 20

How do you calculate an instantaneous heart rate?

Answer 20

R-R interval

Question 21

What is an example of a situation where you may need to calculate multiple heart rates?

Answer 21

Multiple rhythms, e.g. A-V block (separate atrial and ventricular rhythms)

Question 22

Why are T waves very variable?

Answer 22

Show repolarisation of an abnormal depolarisation

Question 23

What is MEA usually in the dog?

Answer 23

Towards lead II (aVF)

Question 24

What is MEA like in cats?

Answer 24

Much more variable

Question 25

What does a left anterior fascicle block look like on ECG?

Answer 25

QRS normal or prolonged, left axis shift, deep S waves in II, III and aVF

Question 26

What does a left bundle branch block look like on ECG?

Answer 26

wide QRS, positive QRS in I-III and aVF

Question 27

WHat does a right bundle branch block look like on ECG?

Answer 27

wide QRS, deep S wave in I-III and aV, right axis shift