LLB - Syncope / presyncope - think WOBBLER

Syncope is a very common presentation to the ED.

The ECG is a vital investigation in the context of a transient loss of consciousness / syncope as it can identify the cause, including rare conditions that can lead to sudden cardiac death.

The pneumonic WOBBLER can be used as a useful way of asessing the ECG in this context with consideration for these rare causes.

W - Wolff-Parkinson-White syndrome –  A short PR interval and delta wave:

O - Obstructed AV pathway – look for 2nd or 3rd degree block:
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2nd degree block:
Mobitz type 1 - PR prolongs then QRS not present:

Mobitz 2 - PR Is constant but QRS randomly not present:

3rd Degree block - complete dissociation between P waves and QRS complexes:

B - Bifascicular block - The combination of axis deviation and right bundle branch block:
Bifasicular block has a low risk of deteriorating into complete heart block (~ 1% per year) but trifasicular block (Axis deviation, RBBB and prolonged PR) has a greater risk.

B - Brugada - Coved ST elevation (shark fin) followed by a negative T wave in V1-V3

L – Left ventricular hypertrophy - Consider Aortic stenosis and Hypertrophic Obstructive cardiomyopathy (HOCM), these can present with exertional syncope.
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LVH diagnostic criteria - S wave in V2 + R wave in V5 > 35 mm
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E – Epsilon wave - A feature of Arrythmogenic right ventricular dysplasia (ARVD). This is another rare cause of sudden cardiac arrest.

The epsilon wave looks a bit like the J wave of hypothermia and may be associated with T wave inversion in V1-V3:

R - Repolarisation abnormality, such as long or Short QT syndrome.
      A prolonged QT is > 440ms in men or > 460ms in women.
      A QT >500ms is associated with increased risk of Torsades de pointes.
      A QT of <350ms is abnormally short. 

So thats it, next time you see a patient with a transient loss of consiousness make sure thier ECG is not a WOBBLER.

Dr Martin Dore
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