Usefulness of Measuring QT Dispersion for Anesthesia and Surgical Procedures

Electrocardiography (ECG) is a useful monitoring method during anesthesia. Among the numerous ECG parameters, QT dispersion (QTd) is an indicator of instability during ventricle repolarization. According to previous reports, an increase of QTd may be occurred any patients with sympathetic instability. However, almost all such noncardiac patients have a physical status of 1 or 2 according to the American Society of Anesthesiology. Therefore, anesthesiologists should be aware whether the patient’s condition may increase QTd, and should be able to treat unexpected arrhythmia during the perioperative period. Increases in QTd occur during various perioperative anesthetic managements or surgical procedures. Several reports have indicated that stabilizing autonomic excitation with opioids, volatile anesthetics, β-blockers, or magnesium can prevent unexpected ventricular arrhythmia associated with increased QTd during anesthetic induction. Unexpected ventricular arrhythmia can occur intraoperatively during laparoscopic surgery under general anesthesia. Moreover, the QTd increases significantly before anesthetic induction in patients with major depression, and modified electroconvulsive therapy further increases the QTd. The disadvantage of QTd is that it cannot be monitored during the intraoperative period. However, anesthesiologists should understand the meaning of QTd increases, and measuring the QTd preoperatively may facilitate safe management during the perioperative period.