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Haemodynamically stable atrial fibrillation of more than 48 hours’ duration — MRCEM SBA MCQ

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EasyCardiovascular emergenciesHaemodynamically stable atrial fibrillation of more than 48 hours’ durationMRCEM SBA

A 68-year-old man presents with continuous palpitations that began 72 hours ago. His ECG shows atrial fibrillation with a ventricular rate of 138/min. He is alert, his blood pressure is 132/78 mmHg, and there are no signs of acute heart failure or myocardial ischaemia. He has hypertension and type 2 diabetes, takes no anticoagulant, and has no active bleeding or contraindication to anticoagulation. He would consider cardioversion if atrial fibrillation persists. Which initial management plan is most appropriate?

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Correct answer: B — Give heparin and initiate beta-blocker rate control; defer cardioversion until after three weeks of therapeutic anticoagulation.

He is haemodynamically stable, so emergency cardioversion is not indicated. Because atrial fibrillation began more than 48 hours ago, NICE recommends rate control at acute presentation. For new-onset atrial fibrillation without existing therapeutic anticoagulation, it recommends heparin initially while stroke and bleeding risks are assessed and appropriate ongoing antithrombotic treatment is established. If longer-term rhythm control is pursued, cardioversion should be deferred until at least three weeks of therapeutic anticoagulation. His hypertension and diabetes also make assessment for ongoing oral anticoagulation important. ([nice.org.uk](https://www.nice.org.uk/guidance/NG196/chapter/recommendations)) A would fit life-threatening instability, which he does not have. C is attractive because flecainide can be used for pharmacological cardioversion in selected patients, but it could restore sinus rhythm before the required anticoagulation period. D substitutes aspirin for anticoagulation and leaves the three-week prerequisite unmet. E recognises the need for anticoagulation but shortens the conventional precardioversion period to 48 hours; an expedited transoesophageal echocardiography-guided strategy would require a separate specialist decision. ([nice.org.uk](https://www.nice.org.uk/guidance/NG196/chapter/recommendations))

Reference: NICE NG196: Atrial fibrillation—diagnosis and management, recommendations 1.8.1–1.8.2 (2021) — https://www.nice.org.uk/guidance/NG196/chapter/recommendations NICE NG196: Atrial fibrillation—diagnosis and management, recommendations 1.8.6 and 1.8.8 (2021) — https://www.nice.org.uk/guidance/NG196/chapter/recommendations