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Unstable atrial fibrillation — SCE Acute Medicine MCQ

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HardCardiovascular medicineUnstable atrial fibrillationSCE Acute Medicine

A 69-year-old man is found to have new atrial fibrillation at 146/min during admission for pneumonia. BP is 92/54 mmHg, he is clammy and has pulmonary oedema on examination. ECG confirms irregular narrow-complex tachycardia without pre-excitation. He has received oxygen and IV access. What is the most appropriate next step in management?

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Correct answer: E — Perform urgent synchronised DC cardioversion with appropriate sedation

This is atrial fibrillation with life-threatening adverse features: shock and pulmonary oedema. Resuscitation Council guidance prioritises synchronised DC cardioversion in unstable tachyarrhythmia. Rate-control drugs are appropriate in stable AF, while adenosine is for regular narrow-complex SVT rather than irregular AF.

Reference: Resuscitation Council UK ALS 2025