QT-Syndrome

Abstract

Long QT syndromes are characterized by prolongation of the QT interval on the surface electrocardiogram and recurrent spontaneous episodes of ventricular tachyarrhythmias of the torsade de pointes-type. Recurrent syncope is the leading symptom, however, the arrhythmia may also degenerate into ventricular fibrillation thereby causing sudden cardiac death. A congenital and an acquired form of the disease can be distinguished. The congenital form has recently been identified as an ion-channelopathy, i.e. mutation in genes encoding for ion channels have been found. However, the mechanisms leading to acquired long QT syndrome are far from being understood. Only in a minority of patients, gene mutations have so far been identified. Although long QT syndromes are uncommon, they have significantly improved our knowledge about the mechanisms of arrhythmias and sudden cardiac death; the disorder has become a paradigm for a genetically based hypothesis of sudden cardiac death.