[Congenital long QT syndrome: an elective indication for betablocker treatment. Apropos of 5 cases]

Abstract

The authors report 5 cases of the long QT syndrome. The patients had malaises and syncopes triggered by exercise or emotional stress, occurring before 10 years of age. The diagnosis was delayed by an average of 38 months (range: 2 to 72 months) from the first symptom and systematic familial study which was positive in 4 of the 5 cases. The corrected QT intervals varied from 0.46 to 0.56 second. All patients were prescribed the betablocker nadolol, resulting in total regression of symptoms with no deaths during an average follow-up period of 40 months (range: 26 to 64 months). The long QT syndrome is a rare hereditary disorder comprising several entities. Recent genetic advances have improved our understanding of the condition. All have an idiopathic prolongation of the QT interval (> 0.44 second) in common with a predisposition to syncope due to torsades de pointes which may cause sudden death. The spontaneous arrhythmic mortality, which was early and high, has been remarkably decreased by betablocker therapy, from 73% to 6% at 10 years. The authors find nadolol to be extremely reliable and well tolerated, and recommend it as the drug of choice in this indication.