ECG interpretation is one of the most frequently tested skills in the ACEM fellowship exam. ECG images appear in MCQs as clinical stems, and the ability to rapidly identify critical patterns is essential. The exam tests not just pattern recognition, but the clinical decisions that follow from specific ECG findings.
How the exam tests ECG skills
Fellowship-level ECG questions rarely ask you to simply name a rhythm. Instead, they present an ECG within a clinical context and ask what you should do next, or which diagnosis best explains the clinical picture. The ECG is the clue, not the answer — you need to integrate it with the clinical scenario.
High-yield ECG patterns
STEMI and STEMI equivalents
Beyond classic ST elevation, you must recognise STEMI equivalents including de Winter T-waves, Wellens syndrome (types A and B), posterior STEMI (ST depression V1–V3 with dominant R waves), and hyperacute T-waves. Sgarbossa criteria for STEMI in the context of LBBB or paced rhythm are frequently tested.
Arrhythmias
Focus on arrhythmias that require emergency intervention: unstable SVT, VT vs SVT with aberrancy (Brugada criteria), torsades de pointes, complete heart block, and symptomatic bradycardia. Know the specific management for each, including cardioversion thresholds, drug choices, and pacing indications.
Toxicological ECG changes
QRS prolongation in sodium channel blocker toxicity (TCAs, local anaesthetics), QTc prolongation and torsades risk, bradycardia patterns in beta-blocker and calcium channel blocker overdose, and the classic digoxin ECG (reverse tick ST changes, regularised AF suggesting toxicity). These questions bridge cardiology and toxicology domains.
Electrolyte abnormalities
Hyperkalaemia progression (peaked T-waves, QRS widening, sine wave) is a favourite exam topic because it is both life-threatening and has specific ECG-guided management thresholds. Hypokalaemia (U-waves, ST depression, QT prolongation) and hypocalcaemia (QTc prolongation) are also tested.
Other high-risk patterns
Brugada pattern (Type 1 with coved ST elevation in V1–V2), Wolff-Parkinson-White (short PR, delta wave, and the management of AF in WPW), and right heart strain patterns suggesting pulmonary embolism (S1Q3T3, right axis deviation, RBBB with anterior T-wave inversion).
Systematic approach
Under exam pressure, a systematic approach prevents you from missing findings. Use a consistent method: rate, rhythm, axis, intervals (PR, QRS, QTc), ST segment and T-wave morphology, and then pattern recognition. Practise this approach enough that it becomes automatic.
Common exam pitfalls
- Diagnosing STEMI without checking for reciprocal changes or considering other causes of ST elevation (pericarditis, benign early repolarisation, LVH)
- Misidentifying artefact as arrhythmia in a moving or shivering patient
- Forgetting to calculate QTc (not just QT) using Bazett’s formula
- Missing subtle posterior STEMI when only anterior leads are considered
Practice tip: ACEMCQ includes ECG-based questions across cardiology, toxicology, and critical care domains, with referenced explanations. Start a free trial to practise ECG interpretation in exam conditions.