Torsades de pointes observed in the early postoperative period in a patient with long QT syndrome

Corresponding author: Yong Seon Choi, M.D., Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, 50, Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea. Tel: 82-2-2227-4576, Fax: 82-2-364-2951, E-mail: [email protected] This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. CC Long QT syndrome (LQTS) is an arrhythmogenic cardiac disorder that may occur congenitally as a result of mutations in genes encoding critical ion channels of the heart, metabolic abnormalities or drugs. Agents routinely used in general anesthesia, physical and emotional stress, enhanced sympathetic tone, and electrolyte imbalance during the perioperative period have been suggested to contribute to the development of torsades de pointes in patients with LQTS [1,2]. Therefore, in these patients, special attention and careful management are required to prevent fatal arrhythmia during the perioperative period. A 56-year-old Asian female (height 169.4 cm, weight 35 kg) had undergone staging laparotomy due to ovarian cancer 20 months prior to presentation. At that time she presented with a prolonged QTc interval (QTc = 514 ms) associated with syncope and a family history of unexplained sudden death of her brother, but the cardiac evaluation was mainly focused on assessing the presence of coronary artery occlusive disease since her father had angina. Cardiac evaluation including echocardiography, a treadmill test and computed tomography coronary angiography demonstrated no specific abnormal findings. Anesthesia was induced with 250 mg thiopental and a 0.5 μg/kg bolus of remifentanil and was maintained with 0.10.2 μg/kg/min remifentanil and sevoflurane (1.5-2.0 vol%). Approximately 3 hr after surgery, cardiac arrest due to torsades de pointes developed suddenly. Her electrocardiographic abnormalities were retrospectively reviewed. We found that the total LQTS score was 7; QTc interval > 480 ms: 3, torsades de pointes: 2, and syncope upon exertion or emotion: 2; hence she was diagnosed as having a high probability of LQTS in the absence of genetic testing [3]. Epinephrine provocation and isoproterenol tests were also positive. The patient was discharged on the 18th postoperative day with prescriptions for oral propranolol and potassium. At the most recent presentation, the patient underwent elective segmental resection of the small bowel due to intestinal obstruction. Preoperative ECG showed T-wave inversion in leads V1-6 and a prolonged QT interval (QTc = 566 ms). The patient was medicated with propranolol and potassium chloride until the morning of surgery. A defibrillator and all necessary antiarrhythmic drugs for the management of torsades de pointes were prepared before induction of anesthesia; propofol and remifentanil was administered with effect site concentrations of 4.0 μg/ml and 4.0 ng/ml, respectively, using a target-controlled infusion device (Orchestra, Fresenius Vial S.A, France). During operation, all electrolyte levels were maintained within normal ranges. There were no remarkable events during anesthesia maintenance. After extubation, the patient was transferred to the intensive care unit (ICU), where her vital signs were stable and pain scores measured on a visual analog scale (VAS) were between 20 and 50. Approximately seven hours after surgery, the patient complained of severe abdominal pain (VAS 80) and a blood pressure increased (178/96 mmHg) with a heart rate of 79 beats/minute. She suddenly complained of palpitation and her ECG indicated ventricular bigeminy, ventricular tachycardia,