Sevoflurane progressively prolongs the QT interval in unpremedicated female adults

Thirty-six unpremedicated women due for gynaecological surgery were examine d for time-dependent prolongation of the OT interval in the electrocardiogr am (ECG) before and after induction of anaesthesia using either sevoflurane or propofol. The conventional inhalational technique to induce anaesthesia with sevoflurane. ECG recordings were taken before, 2, 5 and 10 min after drug administration. Sevoflurane significantly lengthened (P< 0.001) the he art rate corrected QT interval within 10 min from 434 +/- 5 ms to 459 +/- 6 ms (mean +/- SEM). Already after 2 min of sevoflurane application a trend towards prolongation was visible. The critical value of 440 ms in the rate- corrected QT interval was exceeded in four patients in the sevoflurane grou p (n=18) but in only in one patient in the propofol group (n=18). Rate-corr ected QT interval prolongation caused by sevoflurane needs to be recognized early in order to prevent the critical ventricular tachycardia torsade de pointes.