Atrial Flutter — RACP Adult Medicine MCQ

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EasyCardiologyAtrial FlutterRACP Adult Medicine

A 50-year-old man presents with an ECG showing regular narrow-complex tachycardia at 150 bpm with sawtooth baseline best seen in V1 and inferior leads. What is the most likely ECG diagnosis?

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Correct answer: D — Atrial flutter

Regular narrow-complex tachycardia at exactly 150 bpm with sawtooth flutter waves (best seen in II, III, aVF, and V1) is classic for atrial flutter with 2:1 block. The atrial rate is typically 300 bpm with 2:1 conduction. Adenosine may unmask flutter waves by transiently increasing AV block. Rate control or cardioversion (electrical or pharmacological with ibutilide) is required.

Reference: eTG Cardiovascular – 2024 – Atrial Flutter