ECG

Question 1

What syndrome would a shortened PR interval be indicative of?

Answer 1

Wolf-Parkinson White syndrome

There is a shorter conduction time between atria and ventricles due to presence of an accessory conducting pathway

Question 2

What does it suggest if lead I becomes negative and lead III more positive than lead II?

Answer 2

Right axis deviation

Question 3

What is most often the earliest ECG change seen during MI?

• ST Depression
• Tall peaked T waves
• Tall P waves
• ST elevation

Answer 3

Tall peaked T waves - if seen in a GROUP of leads it suggests early MI. This is due to K+ leaking through the damage membrane over the infarcted area

Question 4

If Tall peaked T waves are seen in ALL leads, what does this suggest?

Answer 4

Hyperkalaemia

Question 5

How do you calculate HR from an ECG?

Answer 5

300/ large squares between R waves

Question 6

What does ST depression classically suggest?

• Myocardial infarction
• Myocardial Ischaemia
• Hypernatraemia
• Hyperkalaemia

Answer 6

Myocardial ischaemia - not infarction
The difference is that ischaemia is only the reduction of blood and oxygen flow to the heart, whereas infaction all blood flow has stopped and myocardial cells die

Question 7

Which view of the heart do leads I, aVL, V5 and V6 represent?

Answer 7

Lateral

Question 8

What do you see in Mobitz Type 1 - second degree heart block?

Answer 8

Progressive prolongation of the PR interval and regularly dropped QRS complexes

Question 9

What is a common cause of right axis deviation?

Answer 9

right ventricular hypertrophy

Question 10

If there was ST elevation in V3 and V4 what artery is most likely to be affected?

• Right coronary
• Left circumflex
• Left anterior descending
• All of the above

Answer 10

Left anterior descending - V3 and V4 look at the heart anteriorly therefore suggesting an anterior infarct (most supply anteriorly is by this artery)

Question 11

What is the most common cause of left axis deviation?

Answer 11

Conduction system defects - rarely due to LVH

Question 12

What is the normal duration of the PR interval?

Answer 12

0.12 - 0.2 seconds (3-5 small squares)

Question 13

An absence of P waves and an irregular rhythm would suggest what?

Answer 13

Atrial fibrillation

Question 14

What view of the heart to leads V1-V2 represent?

Answer 14

Septal

Question 15

What view of the heart do leads II, III and avF represent

Answer 15

Inferior

Question 16

What is the normal duration of a QRS complex

Answer 16

0,12 seconds - 3 small squares

Question 17

What would a broad QRS complex indicate?

Answer 17

Inefficient conduction of the ventricles e.g in bundle branch block