The syndrome of long QT interval frequently follows to syncope or a sudden cardiac death on the basis of originated polymorphic ventricular tachycardia of the „torsade de pointes“ type. The prolongation of the QT interval in the hereditary form is based on mutation of the genes responsible for the formation of sodium and potassium channels. The authors analyze the occurrence, clinical findings, therapy and genetic and electropathophysiological connections of the most frequently occurring genotype LQT1, LQT2 and LQT3 as well as the acquired forms of the syndrome of long QT interval.

        Key words: Syndrome of long QT interval - Genotypes LQT1, LQT2 and LQT3 - Syncope - Torsade de pointes