ECG interpretation

Question 1

What two things can always be said about rhythms which originate in the ventricles? (2)

Answer 1

Always patholgical; always have a broad QRS (greater than 0.12 seconds, or three small squares)

Question 2

Why is ventricular tachycardia an emergency?

Answer 2

Can impair cardiac output (haemodynamically unstbale), thus depriving the myocardium of oxygen and causing to degenerate into ventricular fibrillation -> asystole

Question 3

What is the commonest mechanism of ventricular tachycardia?

Answer 3

Re-entry mechanism due to cardiac wall damage e.g. previous infarction

Question 4

Distinguighing between LBBB and RBBB?

Answer 4

Left = WilliaM (W in v1, M in v6)

Right- MorroW

Question 5

Cardiac axis:

leads I and II +ve

Answer 5

Normal axis

Question 6

Cardiax axis:

lead I negative

Answer 6

Right axis deviation

Question 7

Cardiac axis:

Lead I positive, leads II and III negative

Answer 7

Left axis deviation

Question 8

Serial ECG changes in infarction? (4)

Answer 8

Peaked T waves
ST elevation
“Pathological” q waves
T wave inversion

Question 9

New onset LBBB is a sign of…?

Answer 9

myocardial infarction

Question 10

ST-elevation which is more slanting and occurs in younger people?

Answer 10

Pericarditis

Question 11

ST-depression in V1-V3?

Answer 11

Posterior infarction

Question 12

ECG changes in COPD? (4)

Answer 12

RAD
Low voltage QRS complexes particularly in V5-V6
Peaked P-waves in the inferior leads
Right ventricular strain pattern

Question 13

Features of right ventricular strain pattern?

Answer 13

ST depression and and T-wave inversion in inferior leads (II, III and aVF) and V1-V4

Question 14

ECG signs of hypothyroidism? (3)

Answer 14

Bradycardia
Low QRS voltage
Widespread T wave inversion

Question 15

Prolonged QT indicates which metabolic disturbance?

Answer 15

Hypocalcaemia

Question 16

ECG changes in hypercalcaemia? (2)

Answer 16

Short QT

J-waves- notching of the terminal QRS complex

Question 17

Metabolic disturbance causing reduced myocardial excitability –> depressed pacemaking and conduction

Answer 17

Hyperkalaemia

Question 18

ECG signs of hyperkalaemia? (5)

Answer 18

Peaked T waves (earliest sign)
Wide flat P waves
Conduction abnormalities ( lengthened PR interval, QRS duration)

Question 19

Concave ST elevation, PR depression and sinus tachycardia can be signs of?

Answer 19

Pericarditis

Question 20

ECG changes in pulmonary embolism? (5)

Answer 20

Sinus tachy
RBBB
Right ventricular strain pattern
Right axis deviation
S1 Q3 T3

Question 21

ECG changes in left ventricular hypertrophy?

Answer 21

Increased QRS amplitude in leftsided ECG leads (I, avL and V4-V6)
Left axis deviation
Left ventricular strain pattern

Question 22

What is the left ventricular strain pattern?

Answer 22

ST depression and T wave inversion in the left sided leads

Question 23

Left-sided ECG leads?

Answer 23

I, avl and V4-V6

Question 24

Right-sided ECG leads?

Answer 24

II, III and avF (the inferior leads)

V1-V4

Question 25

ECG features of hypokalaemia? (5)

Answer 25

U waves
Small or absent T waves
Long QT
ST depression
Prolonged PR

Question 26

Normal QRS?

Answer 26

<0.12 seconds (three small boxes)

Question 27

Normal PR interval?

Answer 27

Between 0.12 and 0.20 (three-five small boxes)