ECGs

Question 1

what is seen in LBBB?

Answer 1

WiLLiaM MaRRoW

In LBBB there is a ‘W’ in V1 and a ‘M’ in V6

Question 2

Causes of LBBB?

Answer 2

MI
Hypertension
Aortic stenosis
Cardiomyopathy
Rare: idiopathic fibrosis, digoxin toxicity, hyperkalaemia

Question 3

Is LBBB always pathological?

Answer 3

Yes, if it is new, always pathological

Question 4

What is seen on RBBB?

Answer 4

WiLLiaM MaRRoW

in RBBB there is a ‘M’ in V1 and a ‘W’ in V6

Question 5

Causes of RBBB?

Answer 5

normal variant - more common with increasing age

Right ventricular hypertrophy

Chronically increased right ventricular pressure e.g. cor pulmonale

Pulmonary embolism

MI

Atrial septal defect (ostium secundum)

Cardiomyopathy of myocarditis

Question 6

Acute MI signs on ECG?

Answer 6

Hyperacute T waves (fat and wide with a more blunted peak) are often the first sign of MI but often only persists for a few minutes

ST elevation may then develop

The T waves typically become inverted within the first 24 hours. The inversion of the T waves can last for days to months

Pathological Q waves develop after several hours to days. This change usually persists indefinitely

Question 7

Definition of ST elevation MI (STEMI)

Answer 7

Clinical symptoms consistent with ACS (generally of around 20 minutes) with persistent ECG features in 2 or more contiguous leads of:

• 2.5mm (≥ 2.5 small squares) ST elevation in leads V2-3 in men under 40 years, or ≥ 2.0mm ( ≥ 2 small squares) ST elevation in leads V2-3 in men over 40 years
• 1.5mm ST elevation in V2-3 in women
• 1mm ST elevation in other leads
• New LBBB (should be considered new unless there is evidence otherwise)

Question 8

What does posterior MI cause on an ECG?

Answer 8

ST depression

Question 9

Causes of peaked T waves?

Answer 9

• hyperkalaemia
• myocardial ischaemia

Question 10

Causes of inverted T waves?

Answer 10

• MI
• digoxin toxicity
• subarachnoid haemorrhage
• arrhythmogenic right ventricular cardiomyopathy
• pulmonary embolism
• brugada syndrome

Question 11

Causes of increased P wave amplitude?

Answer 11

cor pulmonale

Question 12

Causes of broad, notched (bifid) P waves?

Answer 12

Often most pronounced in lead II

often a sign of left atrial enlargement, classically due to mitral stenosis

Question 13

P waves in AF?

Answer 13

absence of P waves

Question 14

Bifascicular block?

Answer 14

The combination of RBBB with left anterior or posterior hemiblock

e.g. RBBB with left axis deviation

Question 15

Trifascicular block

Answer 15

Features of bifascicular block + 1st degree heart block

Question 16

ECG features of Hypokalaemia?

Answer 16

U waves (immediately follows the T wave)
small of absent T waves (occasionally inversion)
prolong PR interval
ST depression
long QT

in hypokalaemia, U have no Pot and no T, but a long PR and a long QT

Question 17

ECG: hypothermia

Answer 17

bradycardia
‘J’ wave (Osborne waves) - small hump at the end of the QRS complex
first degree heart block (long PR interval)
long QT interval
atrial and ventricular arrhythmias

Question 18

Causes of ST depression?

Answer 18

secondary to abnormal QRS (LVH, LBBB, RBBB)
ischaemia
digoxin
hypokalaemia
syndrome X

Question 19

Digoxin ECG features:

Answer 19

down-sloping ST depression (‘reverse tick’, ‘scooped out’)
flattened/inverted T waves
short QT interval
arrhythmias e.g. AV block, bradycardia

Question 20

Causes of left axis deviation (LAD)

Answer 20

left anterior hemiblock
left bundle branch block
inferior myocardial infarction
Wolff-Parkinson-White syndrome* - right-sided accessory pathway
hyperkalaemia
congenital: ostium primum ASD, tricuspid atresia
minor LAD in obese people

Question 21

Causes of right axis deviation (RAD)

Answer 21

right ventricular hypertrophy
left posterior hemiblock
lateral myocardial infarction
chronic lung disease → cor pulmonale
pulmonary embolism
ostium secundum ASD
Wolff-Parkinson-White syndrome* - left-sided accessory pathway
normal in infant < 1 years old
minor RAD in tall people

Question 22

what is seen in left ventricular hypertrophy

Answer 22

sum of S wave in V1 and R wave in V5 or V6 exceeds 40mm

Question 23

what is seen in left atrial enlargement?

Answer 23

bifid P wave in lead II with a duration >120ms

In V1 the P wave has a negative terminal portion

Question 24

what is seen in right atrial enlargement?

Answer 24

tall P waves in both II and V1 with exceed 0.25mV

Question 25

A short PR interval is seen in?

Answer 25

Wolff-Parkinson-White syndrome

Question 26

Causes of a prolonged PR interval

Answer 26

idiopathic
ischaemic heart disease
digoxin toxicity
hypokalaemia (rarely)
rheumatic fever
aortic root pathology e.g. abscess secondary to endocarditis
Lyme disease
sarcoidosis
myotonic dystrophy

Question 27

ECG features: Wellen’s syndrome

Answer 27

Wellen’s syndrome is an ECG pattern that is typically caused by high-grade stenosis in the left anterior descending coronary artery.

The patient’s pain may have resolved at the time of presentation and cardiac enzymes may be normal/minimally elevated.

biphasic or deep T wave inversion in V2-3
minimal ST elevation
no Q waves

Question 28

Causes of ST elevation ?

Answer 28

myocardial infarction
pericarditis/myocarditis
normal variant - ‘high take-off’
left ventricular aneurysm
Prinzmetal’s angina (coronary artery spasm)
Takotsubo cardiomyopathy
rare: subarachnoid haemorrhage

Question 29

ECG: First degree heart block

Answer 29

PR interval > 0.2 seconds

Question 30

Second degree heart block

Answer 30

type 1 (Mobitz I, Wenckebach): progressive prolongation of the PR interval until a dropped beat occurs

type 2 (Mobitz II): PR interval is constant but the P wave is often not followed by a QRS complex

Question 31

Third degree (complete) heart block

Answer 31

there is no association between the P waves and QRS complexes

Question 32

the following ECG changes are considered normal variants in an athlete:

Answer 32

Sinus bradycardia
Junctional rhythm
First degree heart block
Mobitz type 1 (wenckebach phenomenon)