J Korean Pediatr Soc.  1999 Sep;42(9):1317-1321.

Two Cases of 2:1 Atrioventricular Block in Infants with Idiopathic Long QT Syndrome

• Kim IJ
• Kim BJ
• Ma JS

Abstract

Idiopathic long QT syndrome(LQTS) is an important cause of syncope, seizures, serious ventricular arrhythmias and sudden death in children. The abnormalities of AV conduction such as 2:1 AV block in children with LQTS is rarely reported. We reported two cases of 2:1 atrioventricualr block in infants with LQTS. Patient 1, a female newborn, revealed bradycardia(60 beats/min) and QTc of 0.65sec with 2:1 AV block at birth. She died of polymorphic ventricular tachycardia at 26days of age. Patient 2, a 2-month-old female, exhibited prolonged QT interval (QTc=0.54sec), 2:1 AV block, and intermittent Wenckebach conduction. After she received propranolol, sinus rhythm with 1:1 AV conduction and QTc of 0.5sec was seen. After a follow-up of 6 months, the infant is still doing well.

Keyword

Long QT syndrome; 2:1 AV block; Infant

MeSH Terms

Arrhythmias, Cardiac
Atrioventricular Block*
Child
Death, Sudden
Female
Follow-Up Studies
Humans
Infant*
Infant, Newborn
Long QT Syndrome*
Parturition
Propranolol
Seizures
Syncope
Tachycardia, Ventricular
Propranolol