CONGENITAL LONG QT SYNDROME

The congenital long QT syndrome is characterized by prolongation of the corrected QT interval, polymorphic ventricular tachycardia (torsade de pointes), syncope and sudden death. The identification of several long QT syndrome genes, all encoding cardiac ion channels, has had a major impact on the management strategy for both patients and family members. Acquired causes of the long QT syndrome include drugs, electrolyte imbalance, bradyarrhythmias, myocardial ischemia. Short-term treatment is aimed at preventing the recurrences of torsade de pointes and includes intravenous magnesium and temporary cardiac pacing. Longterm management includes use of beta-blockers, left cardiac sympathetic denervation, permanent pacemaker placement, and cardioverter-defibrillator implantation. The impressive correlation between specific mutations and critical alterations in the ionic control of ventricular repolarization makes this syndrome a unique paradigm which allows to correlate genotype and phenotype, thus providing a direct bridge between molecular biology and clinical cardiology in the area of sudden cardiac death.