Passmedicine ECGs

Question 1

Atrial Enlargement and ventricular hypertrophy

Describe what the ECG will show in the following circumstances

1. LVH
2. left atrial enlargement
3. right atrial enlargement

Answer 1

1. sum of S wave in V1 and R wave on V5/6 > 40mm
2. • lead II: bifid P wave in with duration >120ms
   • V1: P wave has negative portion
3. lead II and V1 show tall P waves >0.25mV

Question 2

Digoxin

What ECG changes can this cause?

Answer 2

• downscoping ST depression
• short QT
• T wave flattening / inversion

Question 3

What changes will be seen in hypokalaemia?

Answer 3

• U waves (deflection after T wave)
• small in magnitude / absent T waves
• prolonged PR + QT intervals
• ST depression

THINK:

• intervals will be prolonged because K less readily available in to transport
• tall-tented T waves in hyperkalaemia so only hypo gonna be the opposite

Question 4

State heart rhythms which can be considered to be normal in an athlete.

Answer 4

• sinus bradycardia
• first degree or mobitz type 1 heart block
• junction rhythm (heartbeat originating at AV node)

Question 5

T wave changes

What can cause

1. peaked T waves
2. inverted T waves

Answer 5

1. • hyperkalaemia
   • myocardial ischaemia
2. • myocardial ischaemia
   • digoxin
   • Brugada syndrome
   • arrhythmogenic right ventricular dysplasia
   • PE (S1Q3T3)
   • subarachnoid haemorrhage

Question 6

Wellen’s Syndrome

1. What causes this ECG pattern?
2. What ECG features are seen?

NOTE: chest pain my have resolved and cardiac markers may be normal / only minimally elevated

Answer 6

1. high grade stenosis of LAD coronary artery
2. • biphasic T wave inversion in V2/3
   • minimal ST elevation
   • NO Q waves

Question 7

Prolonged QT

1. What can it lead to?
2. What can cause it
   a) congenital
   b) drugs
   c) electrolytes
3. How is it managed?

Answer 7

1. VT / torsades de pointes (and therefore collapse or sudden death)

2

a)
- Jervell-Lange-Nielsen syndrome (long QT + deafness)
- Romano-ward (no deafness)

b)
- terfenadine (non-sedating anti-histamine)
- haloperidol
- erythromycin

• chloroquine
• amiodaRone
• anti-Depressants (SSRIs + tricyclic)
• Injecting methadone
• ondansetron

mnemonic: implant THE CARDIO is the management
c) low: calcium, potassium, magnesium

3. • beta-blockers (not sotalol)
   • high risk: implantable cardio-defibrillator