skip to main content

ICD Magnet Effect — FRCA Final MCQ

Instant feedback + full explanation. One question, done properly.

ModerateAnaesthetic Equipment & SafetyICD Magnet EffectFRCA Final

A 50-year-old man with an implantable cardiac defibrillator (ICD) requires emergency surgery. The ICD cannot be reprogrammed pre-operatively due to time constraints. A magnet is placed over the ICD. What is the effect of a magnet on an ICD?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Has no effect on the ICD

Placing a magnet over an ICD suspends tachyarrhythmia detection – the device will NOT deliver anti-tachycardia pacing or defibrillation shocks while the magnet is in place. This prevents inappropriate shocks triggered by diathermy EMI. Pacing function is usually UNAFFECTED (unlike in a pacemaker, where a magnet converts to asynchronous pacing). On magnet REMOVAL, tachyarrhythmia detection is restored (in most manufacturers – some older devices may remain disabled after magnet removal). External defibrillation pads must be placed on the patient before surgery in case real VF/VT occurs.

Reference: Association of Anaesthetists – 2023 – CIEDs and anaesthesia; RCOA – 2023 – Equipment safety