The aim of this study was to describe whether or not spinal anaesthesia with bupivacaine versus levobupivacaine has any effects on the QTc interval during caesarean section. Sixty healthy pregnant women scheduled for elective caesarean section were randomized to spinal anaesthesia with either bupivacaine (the bupivacaine group) or levobupivacaine (the levobupivacaine group). ECG recordings were performed prior to spinal anaesthesia at baseline (T1), 5 min. after spinal anaesthesia, but before uterine incision (T2), and after skin closure (T3). QT intervals were calculated and corrected with the patients' heart rate according to the Bazett formula. Compared with baseline values, mean maximum QTc intervals at T2 and T3 were significantly longer in the levobupivacaine group, but only at T2 in the bupivacaine group. In addition, compared with the bupivacaine group, the QTc maximum interval at T3 was significantly longer in the levobupivacaine group. At T2, the QTc maximum intervals were longer than baseline in both groups. By the end of the surgery, the prolongation of the QTc interval had disappeared in the bupivacaine group but not in the levobupivacaine group.The QT interval is defined as the measurement of time between the start of the Q wave and the end of the T wave in the heart's electrical cycle. The QT interval represents the total period of the left ventricle's depolarization and its repolarization. QT prolongation is associated with increased risk of ventricular arrhythmias, leading to polymorphic ventricular tachycardia (Torsades de Pointes) and ventricular fibrillation [1]. The myocardial conduction changes (prolongation of PQ or QT intervals or QRS widening) are assumed to be early signs of drug-related cardiac toxicity and might be determined even in the absence of any significant changing in contractility [2]. Prolongation of the QT interval can be either hereditary or acquired. It is associated with different medications, as well as cardiac, neurological and electrolyte disorders. Several cardiac and non-cardiac medications, including anaesthetics [3], can also interfere with cardiac repolarization and prolong the QT interval, and sometimes may cause drug-induced Torsades de Pointes and even sudden cardiac death [4][5][6][7].Spinal anaesthesia is commonly used in emergency and elective caesarean section because it provides rapid and adequate anaesthesia. Regional anaesthesia techniques eliminate the increased catecholamine levels that result from laryngoscopy and intubation. Increased plasma catecholamine concentrations and sympathetic activity are related with increased incidence of ventricular arrhythmias and even sudden death because of prolonged QT interval [8,9]. In addition, regional techniques eliminate or decrease the need for induction agents, volatile anaesthetics, opioids, muscle relaxants and neuromuscular reversal intra-operatively and postoperatively, all of which have variable effects on QT intervals [5,10,11]. Both bupivacaine and levobupivacaine (both the L-form and the S ...
