skip to main content

Unstable atrial fibrillation with WPW — RCPSC EM MCQ

Instant feedback + full explanation. One question, done properly.

HardCardiovascular emergenciesUnstable atrial fibrillation with WPWRCPSC EM

CTAS 1: A 29-year-old has palpitations and presyncope. Vitals are BP 78/40, HR 230 irregular, SpO2 96%. ECG shows an irregular wide-complex tachycardia with beat-to-beat QRS variation and delta waves on a prior ECG. He is diaphoretic and confused. What is the most likely diagnosis?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Atrial fibrillation with pre-excitation

Irregular very rapid wide-complex tachycardia with known delta waves is AF with WPW. AV nodal blockers can precipitate ventricular fibrillation; unstable patients need synchronised cardioversion.

Reference: ACLS tachyarrhythmia guidance; Canadian EM arrhythmia practice