Brief review: Anesthetic implications of long QT syndrome in pregnancy

Abstract

Purpose:To review the effects of the long QT syndrome (LQTS) in the parturient and the current anesthetic management of patients with LQTS. Principal findings:The prevalence of LQTS in the developed world is one per 1,100 to 3,000 of the population. Clinically, LQTS is characterized by syncope, cardiac arrest and occasionally, by a history of seizures. The QT interval can also be prolonged by drugs, electrolyte imbalances, toxins and certain medical conditions. Long QT syndrome patients are at risk of torsades de pointes and ventricular fibrillation. Medical management aims to reduce dysrhythmia frequency. The LQTS is subdivided into different groups (LQT1-6) depending on the cardiac ion channel abnormality. Torsades can be precipitated by adrenergic stimuli such as stress or pain (LQT1 and 2), sudden noises (LQT2) or whilst sleeping (LQT3). Patients with LQTS require careful anesthetic management as they are at high risk of torsades perioperatively despite minimal data on the effects of anesthetic agents on the QT interval. While information on effects of LQTS in pregnancy is limited, the incidence of dysrhythmia increases postpartum. Isolated case reports of patients with LQTS women highlight several peripartum dysrhythmias.Conclusion: An understanding of LQTS and the associated risk factors contributing to dysrhythmias is important for anesthesthesiologists caring for parturients with LQTS.

Perioperative management of patients with congenital or acquired disorders of the QT interval

“…115,120 Dexmedetomidine, however, increases the QTc in children. 121 Hypothermia, which can prolong the QT interval, should be avoided by warming the patient in each operative period (before operation, intraoperatively, and after operation) to maintain a temperature of 37 C. 112,122,123 Hypoxia and hypercarbia should also be avoided because of their effect in increasing sympathetic tone. 118 Necessary precautions should be taken for patients with a pacemaker or an ICD.…”

“…136 Epinephrine and ketamine must be avoided because their sympathomimetic properties can induce arrhythmias, including TdP. 112,122,139…”

“…158,161e164 Non-depolarising neuromuscular blockers (rocuronium, vecuronium, and cisatracurium) do not prolong the QTc and can be administered safely. 112,115,122,135,165 Pancuronium, however, should be avoided because of its vagolytic properties; one case of ventricular fibrillation has been reported. 112,118 Prolongation of the QT interval has been reported with anticholinergic medications, such as glycopyrrolate and atropine; atropine-triggered TdP has been documented.…”

Arrhythmias in Pregnancy

“…(Guillon, 2010). Women with a long QT syndrome are more susceptible to ventricular arrythmias during pregnancy, labour, delivery and postpartum (Drake, 2007;Seth, 2007). -Having regular physical exams and promptly reporting any unusual symptoms to a physician.…”

El síndrome de QT largo en anestesia. Una revisión a partir de un caso clínico

“…Para el manejo de la hipotensión se recomienda utilizar agonistas alfa puros como fenilefrina, teniendo en consideración su efecto sobre la frecuencia cardiaca 104 . Durante la ventilación con presión positiva, es necesario evitar las maniobras que imiten una Valsalva, como reclutamiento alveolar o PEEP alto, puesto que también contribuyen a la prolongación del QTc 105,106 . El uso de neumoperitoneo en cirugía laparoscópica tendría el mismo efecto 107 .…”