Long QT Syndrome Anaesthesia — FRCA Final MCQ

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HardPreoperative AssessmentLong QT Syndrome AnaesthesiaFRCA Final

During pre-operative assessment, a 45-year-old woman is found to have a repeatedly prolonged corrected QT interval (QTc) of 520 ms. She takes no QT-prolonging medication and her serum potassium, magnesium and calcium concentrations are normal. Among the following anaesthetic agents, which is associated with the greatest mean QTc prolongation in adult comparative evidence?

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Correct answer: E — Desflurane

Desflurane is correct. Comparative adult randomised evidence indicates that desflurane causes greater mean QTc prolongation than sevoflurane, while propofol has the least effect. UK product information also specifically advises caution with desflurane in congenital or acquired long QT syndrome because QT prolongation and rare torsade de pointes have been reported. Sevoflurane is the strongest distractor: it also prolongs QTc and has been associated with torsade, but its average effect is smaller than that of desflurane in comparative evidence. Propofol generally has little effect or may shorten QTc and is commonly favoured as part of a total intravenous technique. Remifentanil and atracurium are not principal direct QT-prolonging agents. In practice, a QTc of 520 ms warrants investigation, correction of modifiable risks and avoidance of additional QT-prolonging drugs.

Reference: Cai Y et al. Effects of Anesthetics on Cardiac Repolarization in Adults: A Network Meta-Analysis of Randomized Clinical Trials. Heart Surgery Forum. 2023;26(6):E905-E916. https://pubmed.ncbi.nlm.nih.gov/38178332/