Tiny Tip: WOBBLER as an approach to ECGs for syncope

Syncope makes up approximately 1% of acute care visits in Canadian emergency departments and is a common symptom for a wide range of underlying etiologies.^​1​  Identifying any serious underlying condition for syncope and disposition planning is the main area of focus in the emergency department. In addition to a comprehensive history and physical, the 12-lead ECG is a part of the initial evaluation in any patient presenting with syncope.

The mnemonic, WOBBLER can be used as a memory aid for pertinent ECG findings for patients with syncope aside from obvious ischemic changes or dysrhythmias.

W – Wolff-Parkinson-White Syndrome

Delta wave with PR shortening and QRS widening^​2​

O – Obstruction

Obstruction of AV node (e.g. Mobitz type II, third degree heart block) or obstructive causes (pulmonary embolism, cardiac tamponade)

B – Brugada Syndrome

Brugada – Type 1 (Coved ST segment elevation in anterior precordial leads)^​3​

B – Bifasicular block

Right bundle branch block +  Left anterior fasicular block/left posterior fasicular block^​4​

L – Left ventricular hypertrophy

Hypertrophic obstructive cardiomyopathy (HOCM), aortic stenosis. Eg. Voltage criteria for LVH and q-waves found in HOCM^​5​

E – Epsilon

Epsilon wave: arrhythmogenic right ventricular dysplasia. Positive blip found at the end of the QRS complex, best seen in V1-V2^​6​

R – Repolarization

Long QTc (>500 ms) or short QTc (<350 ms). To rule out long QTc, a useful rule of thumb is that a normal QTc is less than half the R-R interval.

This post was edited by Daniel Ting and copyedited by Jeremi Laski.

References

Reviewing with the Staff #1

Life-threatening causes of syncope are primarily cardiac in nature, and thus the ECG becomes a great screening tool for these causes. We must be as good at searching ECGs for dangerous causes of syncope as we are at spotting STEMIs.
The WOBBLER mnemonic, in this case, provides the ED practitioner with a very useful memory aid to search for the other causes of syncope that don’t necessarily “jump out” of the ECG, as do the obvious commonly-seen dysrhythmias.

Gregory Rampersad

Greg is an Emergency Physician at Credit Valley Hospital in Mississauga, and a Lecturer at the University of Toronto, Department of Family and Community Medicine. Interests in Medical Education, technology and Lego. No conflicts of interest to declare.

Reviewing with the Staff #2

When reading EKGs for patients who present with syncope, it is important to remember that some findings in this list can be transient and may not show up on the EKG in the ED. One prominent example is Brugada syndrome. The key in these patients is in the history. Syncope that happens without a prodrome, that results in significant facial trauma, or happens in the context of exertion are key features that warrant cardiology consultation, regardless of the EKG findings.

Daniel Ting

Daniel Ting is the Editor-in-Chief at CanadiEM.org. He is an Emergency Physician at Vancouver General Hospital and BC Children\'s Hospital, and a Clinical Instructor at the UBC Department of Emergency Medicine. He is also a Decision Editor at CJEM, a member of the CAEP Education Scholarship Committee, and a site lead within the CCEDRRN network.

@tingdan

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Garvin Leung

Garvin Leung is a family medicine resident at the University of Toronto. He has academic interests in emergency medicine and medical education. He enjoys drinking endless amounts of coffee and playing basketball in his spare time.

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• Tiny Tip: WOBBLER as an approach to ECGs for syncope - August 10, 2021