AAI Pacemaker Complete Heart Block — FRCA Final MCQ

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HardAnaesthetic Equipment & SafetyAAI Pacemaker Complete Heart BlockFRCA Final

A 68-year-old man (ASA III) with a permanent pacemaker (AAI mode) for sick sinus syndrome develops complete heart block under general anaesthesia. HR drops to 30 bpm and BP to 60/30 mmHg. What is the immediate management?

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Correct answer: D — Transcutaneous pacing while arranging temporary transvenous pacing

An AAI pacemaker only paces and senses the atrium – it provides NO ventricular pacing capability. If this patient develops complete heart block (no AV conduction), the AAI pacemaker cannot pace the ventricles, resulting in a very slow ventricular escape rhythm or asystole. Emergency management: transcutaneous pacing (most rapid), atropine (may help if some AV conduction is present), isoprenaline infusion, and urgent cardiology input for temporary transvenous pacing wire. A magnet over an AAI pacemaker converts to AOO (asynchronous atrial pacing) which still only paces the atrium.

Reference: Association of Anaesthetists – 2023 – CIEDs; Resuscitation Council UK – 2021 – Bradycardia algorithm