QT interval of the ECG, heart rate and arterial pressure during anaesthetic induction: comparative effects of alfentanil and esmolol

Abstract

In a double-blind study the effect of esmolol and alfentanil on the QT interval of the ECG corrected by the heart rate (QTc), heart rate and arterial pressure during anaesthetic induction was studied in 59 oxycodone- and atropine-premedicated ASA class I-(II) patients with a mean age of 26 yr (range 15-50 yr). The patients were randomly allocated to one of the four groups: saline, esmolol 2 mg.kg-1, esmolol 3 mg.kg-1 or alfentanil 0.03 mg.kg-1. Both doses of esmolol prevented the prolongation of the QTc interval after thiopental and suxamethonium, but not after laryngoscopy and intubation. Alfentanil prevented the prolongation of the QTc interval following thiopental, suxamethonium and laryngoscopy but not after intubation. Esmolol did not prevent the increase in the heart rate and arterial pressure in response to laryngoscopy and intubation. No cardiovascular responses to laryngoscopy and intubation occurred in the patients treated with alfentanil. No cardiac arrhythmias occurred in the esmolol 3 mg.kg-1 group, whereas the frequency of ventricular ectopic beats was 40% in the saline group and 13-20% in the other groups.

Effects of target concentration infusion of propofol and tracheal intubation on QTc interval*

“…Generally, it is known that tracheal intubation during induction stimulates sympathetic activity, which, as a result, prolongs the QTc interval [15,16]. In contrast, other studies have shown the opposite, with tracheal intubation decreasing the QTc interval [17].…”

“…In the case of opioids, their influence on the QTc interval and its generation is unclear [7,17]. Moreover, it has been found that alfentanil does not prolong the QTc interval during intubation [24] and also that alfentanil cannot prevent QTc prolongation [16]. Therefore, it is difficult to conclude that sympathetic activity is the main trigger of QTc interval prolongation during tracheal intubation.…”

“…Increased plasma catecholamine is related to QTc prolongation and cardiac arrhythmias. However, Korpinen et al [16] stated that a beta blocker cannot prevent the prolongation of the QTc interval during tracheal intubation. In the case of opioids, their influence on the QTc interval and its generation is unclear [7,17].…”

Effects of fentanyl pretreatment on the QTc interval during propofol induction

“…Rapid injection of catecholamine, brief stimulation of the sympathetic nervous system, and an imbalance of the cardiac sympathetic tone cause prolongation of the QTc interval [15][16][17][18], which may be related to sympathetic stimulation. However, Korpinen et al [10] reported that b-blockers did not attenuate the QTc prolongation during induction of anaesthesia. The effect of opioids on the prolongation of the QTc interval during induction is unclear [13,19,20].…”

“…The administration of a potent opioid or b-adrenergic blockade is generally recommended to attenuate sympathoadrenal responses to laryngoscopy and intubation. However, it has been reported that b-blockers may not attenuate QTc prolongation during the induction of anaesthesia [9,10]. Studies concerning the effects of alfentanil on preventing the prolongation of the QTc interval following intubation are not consistent, depending on different premedication or patient ages [10,11].…”