The purpose of this study was to evaluate the effects of propofol-ketamine combination on QTc, T wave (Tp-e) interval, hemodynamics during the induction of anesthesia in patients with coronary artery disease (CAD) undergoing coronary artery bypass grafting (CABG). Patients were prospectively randomized, in a double blinded manner, to either the propofol group (Group P, n=41) or the propofol-ketamine combination group (Group PK, n=45). In both groups the drugs were infused at an IV dose of 2 mg/kg administered over 30 seconds. After that, 5µg/kg fentanyl and 0.1mg/kg vecuronium were administered and tracheal intubation was performed. ECG recordings were performed prior to induction of anesthesia (baseline, T1), 2 min after the beginning of study drugs (T2), 3 min after vecuronium (immediately before intubation, T3), and 30 s (T4), 1 min (T5) and 5 min (T6) after intubation. Eighty-six patients were evaluated in the study. The baseline QTc interval values were similar between the groups, In Group P, QTc interval increased significantly for T3-T6 in all periods according to baseline value. Also in Group P, QTc interval increased significantly in T4, T5, T6 according to T3. In group PK, QTc interval increased significantly in T3-T6 according to baseline value. Group PK increased significantly in T5 and T6 compared to T3. In both groups a statistically significant change was not found in Tp-e intervals of all periods. Following induction with propofol-ketamine combination, QTc interval did not increase, but it prolonged postintubation QTc interval just like propofol. Assuming that increased repolarization transmural dispersion (TDR) is a reliable indicator of risk of torsade de pointes (TdP), and lack of any change in Tp-e interval, in the presence of depressed hemodynamic response to intubation, we think that this combination can be safely used for the induction of anesthesia in patients with CAD undergoing CABG.
Key words: Propofol; ketamine; QT interval; Tp-e interval