The effect of different doses of esmolol on the QTc interval during induction of anaesthesia in patients

Objective To investigate the effect of esmolol on QT interval during induction of anaesthesia, and the effect of different doses of esmolol on the QTc interval during induction of anaesthesia in patients undergoing laparoscopic cholecystectomy. Methods Sixty patients were pro-spectively randomised to three groups： Control group（group C）, the esmolol Ⅰ group（group E1）, The esmolol Ⅱ group（group E2）. Esmolol was administered as a bolus 0.3 mg/kg, followed by a continuous infusion at 0.1 mg.kg^-1.min^-1 in group E1, Esmolol was administered as a bolus 0.3 mg/kg, followed by a continuous infusion at 0.25 mg.kg^-1.min^-1 in group E2, group C received the same volume of saline. The electrocardiogram was recorded prior to induction of anaesthesia （T0）, 5 rain following the start of drug infusions（T1）, 1 min following etomidate（T2）, 3 min following vecuonium（T3）, 30 s（T4）, 2 min（Ts） and 4 min（T6） after intubation. Results QTc interval at T1, T2, Thin group Ex were （382±11）, （380±6）, （406±13） ms, and in group E2 were （379±13）, （370±11）, （400±7） ms. In group E1 and group E2, QTc interval was significantly shorter at T1, T2 and T4 compared to group C （P〈0.05）. Conclusions QTc interval increased following tracheal intubation during induction of anaesthesia. Infusion of different doses of esmolol can attenuated the QTc interval prolongation associated with tracheal intubation, but in group E1, hypotension and low heart rate is more occurred compared to group E2. Key words: Esmolo;  Tracheal intubation;  QTc interval