Effects of mutations and genetic overlap in inherited long-QT and Brugada arrhythmia syndromes.

Long-QT syndrome (LQTS) is an inherited cardiac disease that is characterised by prolongation of the QT interval on the electrocardiogram and is associated with syncopal episodes, dangerous ventricular arrhythmias of the torsades de pointes type, and a high risk of sudden death on a substrate of a structurally normal heart. Today we know that LQTS is an inherited autosomal dominant arrhythmogenic disease that is caused by mutations in the genes of cardiac ion channels and their subunits. According to the genes involved, the type of syndrome is labelled as LQT1, LQT2, etc. (Table 1).