Atrial fibrillation-rate control — EECC MCQ

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ModerateCardiologyAtrial fibrillation-rate controlEECC

A 69-year-old with NSTEMI underwent PCI and is now in sinus rhythm with no AF. Two days later he develops new-onset AF with RVR (HR 140), hemodynamically stable. What is the preferred initial rate-control agent?

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Correct answer: A — Diltiazem IV bolus/infusion

This is haemodynamically stable new-onset atrial fibrillation with rapid ventricular response after NSTEMI/PCI. The immediate objective, as the question specifies rate control, is AV-nodal blockade. In current UK practice, initial rate control for AF is with either a standard beta-blocker or a rate-limiting calcium-channel blocker such as diltiazem or verapamil, provided there is no acute decompensated heart failure, hypotension, high-grade AV block, or significant LV systolic dysfunction. Since a beta-blocker is not offered, IV diltiazem bolus followed by infusion is the best answer. Amiodarone is not first-line rate control in a stable patient; it is mainly used for rhythm control or when usual AV-nodal blockers are unsuitable. Digoxin has slower onset and is less effective in high sympathetic states such as acute illness/post-MI, so it is not preferred first-line here. Adenosine treats AVNRT/diagnostic narrow-complex tachycardia and will not provide sustained control of AF. Lidocaine is for ventricular arrhythmias, not AF rate control.

Reference: NICE Guideline NG196: Atrial fibrillation: diagnosis and management, recommendations 1.7.2 and 1.8.3, 2021. https://www.nice.org.uk/guidance/ng196/chapter/recommendations