Impact of anaesthetic drugs and adjuvants on ECG markers of torsadogenicity

Drug-induced prolongation of cardiac repolarization may trigger malignant ventricular arrhythmias, such as torsade de pointes. The duration of QT interval, QT corrected for heart rate (QTc), JT interval, QT dispersion (QTd), QT variability index, and transmular dispersion of repolarization (TDR) are ECG markers of torsadogenicity. All volatiles, especially isoflurane and desflurane, have been found to prolong QTc and QTcd, while sevoflurane has probably no effects on TDR. Among i.v. anaesthetics, propofol seems superior due to its minimal effects on QTc and TDR; moreover, a decrease in QTc and QTcd has been demonstrated in many studies. Regarding opioids, fentanyl, alfentanil, and remifentanil produce no effects on QTc, while sufentanil, at high doses, may induce QT prolongation. Succinylcholine, but not the non-depolarizing neuromuscular blockers, produces QTc prolongation which can be attenuated by opioids and β-blockers. Reversal of neuromuscular block with anticholinesterase-anticholinergic combinations has been associated with significant QTc prolongation, while such an effect has not been demonstrated for sugammadex, even at high doses. Local anaesthetics have probably no intrinsic action on duration of repolarization; nevertheless, an extensive subarachnoid sympathetic block may increase the duration of QTc. On the contrary, thoracic epidural anaesthesia has been associated with a decrease in both QTc and TDR. Among adjuvants, midazolam seems to have no effect on QTc and TDR, while commonly used antiemetics, such as droperidol, domperidone, and most 5-HT 3 antagonists, produce significant QT prolongation. The effects of anaesthetic drugs and techniques on electrocardiographic torsadogenic markers should be considered in the perioperative management of patients with preexisting repolarization abnormalities. © 2013 © The Author [2013]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: [email protected]

Perioperative management of patients with pre-excitation syndromes

Patients with pre-excitation abnormalities are at a high risk for life-threatening perioperative arrhythmias. In Wolff-Parkinson-White syndrome, the anaesthetics used for invasive diagnostic testing/ablation, should not affect cardiac electrophysiology; propofol, sevoflurane, fentanyl, sufentanil, alfentanil are suitable. In non-ablative surgery, propofol, sevoflurane, isoflurane, fentanyl, alfentanil, sufentanil have been used safely. Among neuromuscular blockers, cis-atracurium, rocuronium and vecuronium are good choices. Ketamine, pancuronium and pethidine should be avoided because of their sympathomimetic actions. Anticholinergic/ anticholinesterase combinations for neuromuscular block reversal should preferably be omitted, while sugammadex seems more attractive. In regional anaesthesia, addition of epinephrine and high sympathetic blocks should be avoided. Hypotension should be treated with pure alpha-adrenergic agonists. Other preexcitation abnormalities associated with different accessory pathways are the Mahaim Fiber and Lown-Ganong-Levine syndrome. Sympathetic activation should be avoided. Total intravenous anaesthesia with propofol probably represents the safest option. A careful anaesthetic plan and close cooperation with cardiologists are mandatory for successful management. © 2018, Editura Clasium. All rights reserved