Congenital complete atrioventricular block associated with QT prolongation: Description of a patient with an unusual outcome.
The association of a complete atrioventricular block with long QT syndrome is relatively common and carries a high risk of torsades de pointes (TdP) and sudden death. It is probably due to a downregulation of potassium channel currents (I (Ks) and I (Kr)) that impairs ventricular repolarization, prolongs the QT interval and increases susceptibility to TdP, so it must be considered a channelopathy. This report describes a 6 year-old boy, with a complete atrioventricular block diagnosed at 5 months of age, who at the age of 1 year started having episodes of TdP associated with a prolonged QT interval. He was treated successfully with propranolol and with a pacemaker implant. At age 3 the complete atrioventricular block reversed spontaneously to a first degree atrioventricular block.
Mendoza
Alberto
A
Pediatric Heart Institute, Hospital 12 de Octubre, Avda de Córdoba s/n, 28041, Madrid, Spain. amendozas.hdoc@salud.madrid.org
Belda
Silvia
S
Salguero
Rafael
R
Granados
Miguel Angel
MA
D054537:Atrioventricular Block / Q000151:congenital* / Q000503:physiopathology / Q000628:therapy; D002304:Cardiac Pacing, Artificial / Q000379:methods; D004562:Electrocardiography; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007223:Infant; D008297:Male; D013997:Time Factors