Female gender: risk factor for congenital long QT-related arrhythmias.

Congenital long-QT syndrome (LQTS) is a genetic cardiac channelopathy in which patients exhibit delayed ventricular repolarization that appears as a prolongation of the corrected QT (QTc) interval on the electrocardiogram. More than 200 mutations have been found in 13 different genes encoding ion channels, accessory beta subunits, and regulatory proteins.Most cases of congenital LQTS are the consequence of the dominant inheritance of a given mutation. Kv11.1 mutations are the most frequent ones (45%), followed by those found in Kv7.1 (42%), Nav1.5 (8%), KCNE1 (3%), and KCNE2 (2%). In addition, another type of LQTS, the ‘acquired’ LQTS, has been described, mostly as the consequence of drugs able to prolong the cardiac action potential duration. This lengthening of the cardiac action potential can produce the development of early afterdepolarizations (EADs) and the genesis of a ventricular polymorphic arrhythmia called torsades de pointes (TdP) that, in turn, can result in recurrent spontaneous syncope, seizures, and sometimes sudden cardiac death.