ECG

Question 1

Speed of paper

Answer 1

25mm/s

Question 2

Large square

Answer 2

0.2 seconds

Question 3

Small square

Answer 3

0.04 seconds

Question 4

How to calculate rate

Answer 4

300/ no. of large squares between R-R interval

OR

QRS complexes in rhythm strip x 6

Question 5

Causes of sinus tachycardia >100/min

Answer 5

1. anaemia
2. anxiety
3. exercise
4. Pain
5. Fever
6. Sepsis
7. Hypovolaemia
8. Heart failure
9. PE
10. Pregnancy
11. Hyperthyroid
12. Thiamine deficiency
13. CO2 retention
14. Autonomic neuropathy
15. Sympathomimetics- caffiene, adrenaline,nicotine

Question 6

Causes of sinus bradycardia <60/min

Answer 6

1. Physical fitness
2. Vasovagal attacks
3. Sick sinus syndrome (sinus node dysfunction)
4. Acute MI (Esp. inferior)
5. Drugs- beta blockers, digoxin, amiodarone, verapamil
6. Hypothyroid
7. Hypothermia
8. Increased ICP
9. Cholestasis

Question 7

Normal axis

Answer 7

-30(avL) to +90(aVF)

Question 8

Right axis deviation

Answer 8

+90 to +180

Question 9

Left axis deviation

Answer 9

-30 to -90

Question 10

Left axis deviation causes

Answer 10

1. Left anterior hemiblock
2. Inferior MI
3. VT from LV focus
4. WPW syndrome - more common types
5. LVH

Question 11

Right axis deviation causes

Answer 11

1. RVH
2. PE
3. Anterolateral MI
4. Left posterior hemiblock (rare)
5. WPW - less common types

Question 12

Absent P waves

Answer 12

• AF
• SA block
• Junctional AVN rhythm
• hyperkalaemia

Question 13

Peaked P waves

Answer 13

P pulmonale- Right atrial hypertrophy

Question 14

Bifid P waves

Answer 14

P mitrale- mitral stenosis

Question 15

Pseudo P pulmonale

Answer 15

hypokalaemia

Question 16

PR interval

Answer 16

start of P wave to start of QRS
- 0.12 - 0.2s ( 3-5 small squares)

• Prolonged= AVN block (e.g. heart blocks)
• Short= fast AV conduction through accessory pathway (WPW

Question 17

QRS

Answer 17

• 0.12
• > 0.12= ventricular conduction defect- BBB
• Large QRS= VH

Question 18

2 criterias for LVH on ECG

Answer 18

• Height of S in V1 and R in V6 - if >35 mm then LVH

OR
- Largest R/S in limb leads >20mm

Question 19

Where is Q wave normally seen?

Answer 19

Lateral leads:
V5, V6, a VL and I

anywhere ellse is abnormal

Question 20

Q wave in an abnormal lead is indicative of?

Answer 20

• post MI

Question 21

QRS - delta wave

Answer 21

WPW syndrome

Question 22

QTc duration

Answer 22

0.4 seconds

Start of QRS to end of T

Question 23

Causes of prolong QTc

Answer 23

1. Hypothermia
2. Acute MI
3. Myocarditis
4. Bradycardia (AV block)
5. Head injury
6. U & E balance - hypo K, Ca, Mg
7. Congenital :Romano-Ward, Jervell-Lange-Neilson syndrome
8. Drugs: sotalol , amiodarone, macrolides (erythromycin), quinidine , antihistamines, phenothiazines, tricylics

Question 24

Downsloping ST segment

Answer 24

DIGOXIN

- reverse tick sign

Question 25

Where is T wave normally inverted?

Answer 25

aVR, V1 +/- V2, never V2 alone, occasionally V2/V3

Question 26

Peaked T wave

Answer 26

Hyperkalaemia

Question 27

Which leads is T wave inversion abnormal?

Answer 27

I, II, V4-V6

Question 28

Flattened T wave

Answer 28

Hypokalaemia

Question 29

T inversion in V1-V3

Answer 29

1. normal (p and children) 2. RBBB 3. PE

Question 30

T inverson in V2-V5

Answer 30

1. Subendocardial MI 2. HOCM 3. SAH 4. Lithium

Question 31

T inversion in V4-V6

Answer 31

1. Ischaemia 2. LVH 3, LBBB

Question 32

Hypothermia ECG changes

Answer 32

J waves | Tall late R waves in V1

Question 33

Hyperkalaemia ECG changes

Answer 33

- tall peaked t waves - Broad QRS - Sinusoidal ECG - small/absent P waves - Increased PR interval - V.fib , asystole

Question 34

Hypokalaemia ECG changes

Answer 34

- Flat T waves - ST depression - long QT - ventricular dysarrythmias

Question 35

PE ECG changes

Answer 35

1) normal ECG 2) SINUS Tacchycardia - tachycardia - RAD - R. ventricular strain - AF - S1 Q3 T3

Question 36

R. heart strain signs

Answer 36

S1 Q3 T3 S wave in lead 1 Q wave in lead III Inverted T wave in lead III

Question 37

AF ecg signs

Answer 37

Absent P waves | QRS irregularly irregular

Question 38

Atrial flutter ecg signs

Answer 38

Sawtooth line of atrial depolarisation Regular QRS complexes Variable degree of AV conduction

Question 39

Nodal rhythm

Answer 39

Normal QRS | P waves absent or occur just before or within QRS

Question 40

Ventricular ryhtm

Answer 40

QRS complexes >0.12 with P waves following them

Question 41

1st and 2nd degree heart block causes

Answer 41

- Normal variant - Athletes - Sick sinus syndrome IHD Acute carditis Drugs (digoxin and beta blockers)

Question 42

3rd degree complete heart block causes

Answer 42

- idiopathic (fibrosis) - congenital - IHD - Aortic valve calcification - Cardiac surgery/ trauma - Digoxin toxicity - Infiltration (abscess, granuloma, tumours, parasites)