Increased intra-abdominal pressure during laparoscopic surgery, anesthesia, patient position, and neuroendocrine response may increase the risk of arrhythmia. This study aimed to investigate the perioperative changes in the frontal QRS-T angle in patients undergoing laparoscopic cholecystectomy under general anesthesia. Therefore, electrophysiological parameters at different stages of laparoscopic cholecystectomy were studied using the frontal QRS-T angle and the risk of arrhythmia susceptibility was investigated. This prospective observational study included 48 patients aged 23 to 65 years with an American Society of Anesthesiologists score of 1 to 3 who underwent laparoscopic cholecystectomy in the operating room of Gaziosmanpaşa University Research and Application Hospital. Electrocardiographic recordings were obtained immediately before surgery, immediately before and after intra-abdominal carbon dioxide insufflation, 2 minutes after reverse Trendelenburg, immediately after extubation, and 2 hours postoperatively, and the frontal plane QRS-T angle, QT and QTc interval were studied. Rhythm disturbances, bleeding and complications were recorded. The frontal QRS-T angle, QT and QTc interval were significantly increased with intra-abdominal hypertension (IAH) compared to baseline (P <
.001, P <
.001, P <
.001, respectively). Similarly, frontal QRS-T angle, QT, and QTc interval increased significantly with reverse Trendelenburg position compared to baseline (P <
.001, P <
.001, P <
.001, respectively). The frontal QRS-T angle, which increased with IAH and the reverse Trendelenburg position, significantly decreased immediately after the patient woke up (P <
.001). Heart rate and mean arterial pressure increased significantly with IAH compared to those just before carbon dioxide insufflation (P = .03, P <
.001, respectively). The present study found that IAH induction and reverse Trendelenburg positioning increased the frontal QRS-T angle, QT, and QTc interval in patients undergoing laparoscopic cholecystectomy. These prolonged values may cause serious arrhythmias, particularly in patients with cardiac disease. Therefore, it is very important for anesthetists to be aware of electrocardiographic changes such as arrhythmias in patients undergoing laparoscopic cholecystectomy.