Atrial fibrillation — MCCQE Part 1 MCQ

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HardPalpitationsAtrial fibrillationMCCQE Part 1

A 63-year-old has three symptomatic episodes of ECG-documented counterclockwise typical atrial flutter despite adequate rate-control medication. Left-ventricular function is normal, and he wants the most effective strategy to prevent further flutter. What should be offered?

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Correct answer: D — Cavotricuspid-isthmus catheter ablation

Counterclockwise typical atrial flutter depends on a macro-re-entrant circuit through the cavotricuspid isthmus. Catheter ablation across that isthmus is highly effective and is the preferred definitive strategy for recurrent symptomatic flutter. Rate-control drugs may slow ventricular response but do not reliably prevent recurrence; a pacemaker does not interrupt the circuit. Carotid massage is not definitive therapy for flutter, and being in sinus rhythm at one visit does not remove the recurrence burden. Stroke risk must be assessed and anticoagulation managed using the same risk principles applied to atrial fibrillation, including around cardioversion or ablation, but anticoagulation alone does not address the question's symptom-prevention objective.

Reference: European Society of Cardiology, Supraventricular Tachycardia Guideline: https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Supraventricular-Tachycardia