Sympathetic activity could be increased during robot-assisted laparoscopic gastrectomy, which is performed in a head up position under CO2 pneumoperitoneum.

Stimulation of the sympathetic nervous system prolongs the QT interval and can increases the susceptibility to life threatening cardiac arrhythmias.

Thus the investigators decided to evaluate the heart-rate corrected QT interval (QTc interval) during robotic-assisted laparoscopic gastrectomy.

Inclusion Criteria:

1. ASA class I-II
2. obtaining written informed consent from the patients who were undergoing robot- assisted laparoscopic gastrectomy.

Exclusion Criteria:

1. emergency operation
2. cardiac disease (unstable angina, congestive heart failure, valvular heart disease)
3. ventricular conduction abnormality
4. prior pacemaker insertion
5. abnormal electrolyte values
6. patients who take antiarrythmic agent
7. hepatic or renal failure
8. drug hyperactivity
9. neurological or psychiatric illnesses

Patients who were undergoing robot- assited laparoscopic gastrectomy