RESUMO
The drugs and techniques used in contemporary anaesthesia may provoke numerous side effects, including cardiac rhythm disturbances. The prolongation of the repolarization time, reflected by the QT interval in a surface electrocardiogram, is one of the mechanisms that lead to the occurrence of arrhythmias. In the paper, we present the primary mechanism that is responsible for QT interval prolongation and subsequent torsade de pointes ventricular tachycardia. The influence of anesthetics, regional anesthesia and perioperative supportive therapy on cardiac repolarization is described.
Assuntos
Anestésicos/efeitos adversos , Síndrome do QT Longo/induzido quimicamente , Taquicardia Ventricular/induzido quimicamente , Torsades de Pointes/induzido quimicamente , Adolescente , Adulto , Idoso , Anestesia por Condução/efeitos adversos , Anestesia Geral/efeitos adversos , Criança , Pré-Escolar , Eletrocardiografia/efeitos dos fármacos , Feminino , Humanos , Lactente , Síndrome do QT Longo/fisiopatologia , Síndrome do QT Longo/terapia , Masculino , Pessoa de Meia-Idade , Assistência Perioperatória , Taquicardia Ventricular/fisiopatologia , Taquicardia Ventricular/terapia , Torsades de Pointes/fisiopatologia , Torsades de Pointes/terapia , Adulto JovemRESUMO
Laryngoscopy and tracheal intubation may provoke changes of cardiac repolarisation. The aim of this study was to assess the effect of intravenous lidocaine on the ECG changes induced by laryngoscopy and tracheal intubation. Forty-three female patients were randomly allocated to receive lidocaine (1.5 mg.kg(-1)) or placebo immediately after induction of anaesthesia and changes in the ECG and arterial blood pressure were recorded. Correction of QT interval was calculated using Bazett's formula (QTcb), Fridericia's correction (QTcf), and Framingham formula (QTcF). Transmural dispersion of repolarisation (TDR) was determined as Tpeak-Tend time. There were no changes in the QTc value in the lidocaine group. In the placebo group, significant increases in QTcb, QTcf and QTcF values were observed after intubation compared to either control measurements or to comparative measurements in the lidocaine group. There were no significant differences in TDR either between or within the groups. Lidocaine diminishes prolongation of QTc, induced by tracheal intubation but there is no effect of intubation on TDR.
