ECG

Question 1

1/ normal PR interval

2/ normal QRS interval

Answer 1

1/ 120-200ms

2/ 70-100ms

Question 2

Criteria for LVH:

Causes of LVH:

Answer 2

S wave in V1 + R wave in V5-V6 = >35mm OR R-wave >26-mm in either V5/6 (BMJ on exam)

HTN,
Aortic stenosis

Question 3

Heart Block

1. 1st Degree
2. 2nd Degree
3. Complete Heart Block

Answer 3

1. > 200ms → nil treatment unless symptomatic
2. not all P waves followed by a QRS → pacemaker

Type I (Wenckebach’s) –> progressive prolongation of the PR interval before the missed QRS complex

Type II (Mobitz II) –> absence of progressive prolongation of the PR interval before the missed QRS complex.

3. nil relationship between P waves and QRS → pacemaker

Question 4

What is
1/ Type I mobitz?
2/ Type II mobitz?

Answer 4

Type I (Wenckebach’s) –> progressive prolongation of the PR interval before the missed QRS complex

Type II (Mobitz II) –> absence of progressive prolongation of the PR interval before the missed QRS complex.

Question 5

Bifasicular block

Answer 5

RBBB + Left Axis Deviation

RBBB + Right Axis Deviation

Question 6

Trifascicular block

Answer 6

RBBB + LAD (Or RAD) + heart block (primary or secondary)

Question 7

Characteristic of LBBB and RBBB?

Answer 7

QRS >120ms
LBBB = Deep S Wave in V1, slurred R wave in V6
RBBB = RSR’ pattern in V1, Dominant wide S wave in V6
WiLLiaM MaRRoW

Question 8

1/ When would Atrial Flutter be suspected?

2/ What is it?

Answer 8

1/ 130-170bpm - suspect flutter 130-170bpm - suspect flutter
2/ Atrial rentry rythm

AV ratio 2:1 = most common (150bpm)
AV ratio 3:1 = 100bpm
AV ration 4:1 = 75bpm
Turn ECG around and look at leads II, III, aVF (for saw tooth)

Question 9

WPW ECG features?

Answer 9

PR <120ms
Delta wave – slurring slow rise of initial portion of the QRS
QRS prolongation >110ms

Question 10

What are the causes of a long QT interval

Answer 10

Antiemetics 
Antiarrythmias 
Antipsychotics 
Antidepressants 
Low calcium 
Hypothyroidism

Question 11

1 ) Which leads is TWI significant in?

2) Which leads is TWI a normal variant?

Answer 11

1) . T wave inversion is only significant if seen in leads with upright QRS complexes (dominant R waves).
2) T wave inversion is a normal variant in leads III, aVR and V1.
https: //lifeinthefastlane.com/ecg-library/myocardial-ischaemia/

Question 12

Premature Ventricular Complex (PVC)
1. arises from

2. causes of persistent PVC’s

Answer 12

1. ectopic focus within the ventricles
   PVCs are a normal electrophysiological phenomenon not usually requiring investigation or treatment.
   Frequent or symptomatic PVCs may be due to:

Anxiety
Sympathomimetics
Beta-agonists
Excess caffeine
Hypokalaemia
Hypomagnesaemia
Digoxin toxicity
Myocardial ischemia

(ref: lifeinthefastlane)

Question 13

Hyperkalemia, ECG features?

Answer 13

As the hyperkalaemia progresses, the ECG changes deteriorate: peaked T waves, decreased P waves and QRS widening.
(BMJ examinatoin)