Anaesthesia and transmural dispersion of repolarisation in children

INTRODUCTION: Prolongation of the QT interval is associated with torsades de pointes (TdP), classically in children or young adults with long QT syndromes (LQTS). Any overt or covert predisposition to TdP may be unmasked by perioperative stress. Which anaesthetic drugs are safest to use in these patients? Susceptibility to TdP arises from increased transmural dispersion of repolarisation (TDR) across the myocardial wall, rather than QT interval prolongation per se [1]. Agents that don’t increase TDR would be useful in minimising any increased perioperative risk of TdP. Several anaesthetic drugs prolong the QT interval, but their effect on TDR is unknown. TDR can be measured on the ECG as the time interval between the peak and end of the T wave (Tp-e) [2]. We have investigated the effects of propofol and sevoflurane on the QT and Tp-e intervals in children.