The hemodynamic responses to endotracheal intubation are associated with sympathoadrenal activity. Polymorphisms in the beta1-adrenergic receptor (β₁ AR ) gene can alter the pathophysiology of specific diseases. The aim of this study is to investigate whether the Ser49Gly and Arg389Gly polymorphism of the β₁ AR gene have different cardiovascular responses during endotracheal intubation under sevoflurane anesthesia.

Ninety-one healthy patients undergoing general anesthesia were enrolled. Patients underwent slow inhalation induction of anesthesia using sevoflurane in 100% oxygen. Vecuronium 0.15 mg/kg was given for muscle relaxation. Endotracheal intubation was performed by an anesthesiologist. The mean arterial pressure (MAP), heart rate (HR), and the corrected QT (QTc) interval were measured before induction, before laryngoscopy, and immediately after tracheal intubation. Genomic DNA was isolated from the patients' peripheral blood and then evaluated for the β₁ AR -49 and β₁ AR -389 genes using an allele-specific polymerase chain reaction method.

No differences were found in the baseline values of MAP, HR, and the QTc interval among β₁ AR -49 and β₁ AR -389, respectively. In the case of β₁ AR -49, the QTc interval change immediately after tracheal intubation was significantly greater in Ser/Ser genotypes than in Ser/Gly genotypes. No differences were observed immediately after tracheal intubation in MAP and HR for β₁ AR -49 and β₁ AR -389.

We found an association between the Ser49 homozygote gene of β₁ AR -49 polymorphism and increased QTc prolongation during endotracheal intubation with sevoflurane anesthesia. Thus, β₁ AR -49 polymorphism may be useful in predicting the risk of arrhythmia during endotracheal intubation in patients with long QT syndrome.