ECGs

Question 1

Which leads is T wave inversion normal?

Answer 1

aVR and V1

Question 2

Which condition is characterised by biphasic T waves in V2-3 (or inverted ones) with chest pain?

Answer 2

Wellen’s syndrome - LAD stenosis, high risk of anterior MI in coming days

Question 3

Answer 3

U waves in V2-3 and QT prolongation = hypokalaemia

e.g. due to diarrhoea

In hypokalaemia, U have no pot (K+) and no T (small/absent T waves), but a long PR and a long QT

Question 4

What is seen in hyperkalaemia?

Answer 4

tall, tented T waves,
flattened P waves,
PR prolongation,
broad QRS complexes

Question 5

Answer 5

aVR - ST elevation - ?left main stem disease
V2-6 - T wave inversion

Question 6

How can you check if ST depression in anterior leads is meaning posterior infarct?

Answer 6

Repeat ECG with the leads on the back

Question 7

What is a bifascicular block?

Answer 7

Bifasicular block = RBBB + LAD

Question 8

What is a trifascicular block?

Answer 8

Trifascicular block (Complete) = Bifasicular + 3rd degree Heart block

Trifascicular block (incomplete) = Bifasicular + 1st/2nd degree heart block

Question 9

Answer 9

Incomplete trifascicular block = RBBB + LAD + 1st degree heart block

Question 10

Apart from M pattern in V1 and W in V6, what else is seen in RBBB?

Answer 10

broad QRS > 120 ms
rSR’ pattern in V1-3 (‘M’ shaped QRS complex)
wide, slurred S wave in the lateral leads (aVL, V5-6)

Question 11

Answer 11

RBBB

Question 12

When do you TREAT hyperkalaemia?

Answer 12

If >6.5 alone OR
ECG changes

Question 13

What is the management of hyperkalaemia?

Answer 13

10-20mls of 10% calcium gluconate by slow IV injection
10U actrapid in 50ml of 50% glucose over 10-15min
salbutamol nebs
sodium bicarbonate infusion to correct acidosis

Question 14

An ECG performed shows ST depression in V1-V3 with tall, broad R waves and upright T waves.

What is the next appropriate course of action?

Answer 14

Posterior ECG - Posterior infarction is confirmed by ST elevation and Q waves in posterior leads (V7-9)

Question 15

If fibrinolysis is given for an ACS, when is an ECG repeated?

Answer 15

an ECG should be repeated after 60-90 minutes - transfer urgently for PCI if not resolved

Question 16

Which antibiotic requires you to check ECG first?

Answer 16

Azithromycin - to rule out prolonged QT and baseline liver function tests

Question 17

Answer 17

II, III, aVF = inferior MI

Question 18

Answer 18

anterior MI = V1-4 LAD
AND
pathological Q waves in II, III and aVF so previous inferior MI

Question 19

Define pathological Q wave.

Answer 19

Old and simple definition:
Q-wave of >=0.04 s and an amplitude >=25% of the R-wave in that lead

New definition:

Any Q-wave in leads V2 - V3 >= 0.02 s or QS complex in leads V2 and V3

Q-wave >= 0.03 s and > 0.1 mV deep or QS complex in leads I, II, aVL, aVF, or V4 - V6 in any two leads of a contiguous lead grouping (I, aVL,V6; V4 - V6; II, III, and aVF)

R-wave >= 0.04 s in V1 - V2 and R/S >= 1 with a concordant positive T-wave in the absence of a conduction defect

Question 20

What investigation must be used before using flecainide to cardiovert AF?

Answer 20

Echocardiogram for structural heart disease or ischaemia

Question 21

A CT shows a collection of blood in the subarachnoid space, midline shift, and hydrocephalus. Whilst the patient is being scheduled and prepared for surgery, he becomes haemodynamically unstable and drops his GCS further to 8 out of 15.

What is most likely to been seen on an ECG?

Answer 21

Torsades de pointes i.e. polymorphic ventricular tachycardia

Question 22

Answer 22

The ECG shows Q-waves, ST elevation, and hyperacute T-waves in V2 and V3, diagnostic of myocardial infarction. This patient was later shown to have a left anterior descending (LAD) occlusion.

Question 23

What is a sinusoidal pattern on ECG indicative of?

Answer 23

Severe hyperkalaemia - can also cause loss of P waves, tall tented T waves, broad QRS, VF

Question 24

Name 3 ECG variants which are normal in athletes.

Answer 24

sinus bradycardia
junctional rhythm
first degree heart block
Mobitz type 1 (Wenckebach phenomenon)

Question 25

Name 2 antiplatelet drugs.

Answer 25

clopidogrel, prasugrel and ticagrelor = P2Y12 receptor antagonists

Question 26

Name 2 agents for thrombolysis.

Answer 26

tenecteplase alteplase

Question 27

Answer 27

Hypokalaemia The ECG findings are: prominent U-waves, best seen in precordial leads - V2,4,5. T waves have a 'sine wave' appearance prolonged QTc > 600ms borderline PR interval

Question 28

Answer 28

rsr pattern - rSR' pattern V1 or V2 can be a normal finding or variant in a younger person or athlete. It may also be called an incomplete right bundle branch block

Question 29

Answer 29

Left ventricular hypertrophy - he ECG shows large R waves in the left-sided leads (V5, V6) and deep S-waves in the right-sided leads (V1, V2). There is also ST elevation in leads V2-3.

Question 30

Answer 30

Hyperacute T waves in V2-3 - early sign of MI

Question 31

Answer 31

Ventricular fibrillation - most common cardiac arrest rhythm, usually due to thromboembolic causes Shows irregular waves with varying morphology and amplitude. No P, QRS or T waves can be seen. | CPR and defibrillation required - hyperkalaemia is a cause

Question 32

Answer 32

ventricular tachycardia degenerating into VF

Question 33

Answer 33

Asystole

Question 34

Patient has no pulse but has this ECG:

Answer 34

Pulseless electrical activity - noticed when person loses consciousness; managed by CPR and treat underlying cause if known, and adrenaline IV. Defibrillation cannot be used as it is the myocardial tissue which is the problem not the electical impulses.

Question 35

What are the reversible causes of cardiac arrest?

Answer 35

Question 36

Answer 36

Atrial flutter with 2:1 block - rate is 144. In leads II and V1 you can see that there is more than 1 P wave per QRS complex

Question 36

Answer 36

Hyperkalaemia - tall ‘tented’ T waves, progressive flattening of P waves, prolongation of the PR interval (PR interval > 200 ms) and eventually disappearance of P waves, and broad QRS complexes. Then will change to sine pattern and VF

Question 37

Which artery to the heart is usually dominant?

Answer 37

RCA - SA and AV node are also supplied by this

Question 38

Answer 38

LBBB - look at V1 and V6, WiLLiam MaRRow

Question 39

Answer 39

Widespread ST depression - likely an old STEMI

Question 40

Answer 40

ST depression in anterior leads so posterior MI

Question 41

Answer 41

Anterior lead ST depression so posterior MI

Question 42

Answer 42

Widespread ST elevation – pericarditis

Question 43

Answer 43

Brugada syndrome - cove shape in leads V1 and V2

Question 44

What causes Brugada syndrome?

Answer 44

AD mutation in SCN5A - affects sodium channels and causes channelopathy, changes to electical activity of heart

Question 45

What is the ECG definition of MI?

Answer 45

New and persistent ST-segment elevation in at least two contiguous leads of ≥1 mm in all leads other than leads V2-V3 where the following cut-off points apply: * ≥2.5 mm in men <40 years old * ≥2 mm in men >40 years old * ≥1.5 mm in women regardless of age * 1 mm = 1 small square (at a standard ECG calibration of 10 mm/mV).

Question 46

What are the Sgarbossa criteria used for?

Answer 46

Used to help detect STEMI in the presence of a LBBB which often makes it difficult

Question 47

Answer 47

ST depression T inversion

Question 48

Answer 48

Hypokalaemia - U waves seen, flattened T waves, long PR

Question 49

Answer 49

This ECG is showing sinus tachycardia, the beginning of QRS widening (especially in V3-6), peaked T waves, and ST changes in V1-3, aVR and aVL. The symptoms of lethargy and palpitations are in line with a presentation of hyperkalaemia.

Question 50

What complication is commonly associated with inferior MI?

Answer 50

Inferior so RCA affected which supplies the AV node Therefore likely 1st degree AV block

Question 51

What are the causes of poor R wave progression?

Answer 51

Old MI LVH RVH