A neonate with acquired long QT from placental transfer of medications

Long QT Syndrome (LQTS) can present in the neonate with bradycardia and AV block and confers significant risk for life threatening ventricular arrhythmias. We report a case of a neonate presenting with complex bradyarrhythmias secondary to acquired LQTS after maternal overdose of QT-prolonging medications (haloperidol and sertraline). When the mother was brought in to the delivery center unconscious, fetal bradycardia was noted and the baby was emergently delivered prematurely. The newborn’s initial ECG showed bradycardia with AV node conduction block, rate related His-Purkinje conduction aberration with varying QRS morphology and a QTc >600 ms. She continued to be bradycardic through her first day of life with echocardiogram showing mild cardiac dysfunction. With the elimination of the offending medication from her circulation, the infant’s rate and function abnormalities resolved and QTc normalized. Both haloperidol and sertraline are known to be strong suppressors of the HERG potassium channel that plays an important role in myocardial repolarization and both medications can cross the placenta. Maternal overdose can cause transient QT-prolonging effect similar to that of inherited LQTS type 2. Given the high risk for sudden death in affected newborns, reporting this case is aimed to raise the awareness of acquired LQTS by placental transfer of medication. Early identification of neonates at risk should prompt ECG testing. If long QT is identified, the newborn should be closely monitored with care to avoid any further QT prolonging medications or conditions, until the toxic medication effect resolves.