A multidisciplinary approach to prenatal treatment of congenital long QT syndrome.

A 27-week fetus evaluated for bradycardia and hydrops was found to have anti-SSA-negative 2° atrioventricular block and ventricular tachycardia. A presumptive diagnosis of fetal long QT syndrome was made. Transplacental pharmacotherapy with intravenous magnesium and lidocaine restored sinus rhythm. At 30 6/7 weeks, the infant was delivered due to premature labor. Despite postnatal treatment with mexiletine and propranolol, she developed torsades de pointes. Ultimately, a de novo KCNH2 G628S mutation was diagnosed. She received an implantable cardiac defibrillator at 5 months of age. Early diagnosis and a multidisciplinary approach allowed successful in utero treatment and anticipatory postnatal management. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:168-170, 2017.