Congenital long QT syndrome (LQTS) is characterized by the prolongation of the QT interval, frequent episodes of syncope and Torsades de Pointes (TdP). The clinical features and electrocardiographic findings in Korean patients with LQTS have not been reported.

We retrospectively analyzed the clinical characteristics, ECG features and response to treatments in 11 patients (6 men, 5 women) with congenital LQTS.

The mean age at the time of the first episode was 19.4±22.6 years old (range: 170 years). Clinical presentations were syncope, seizure or sudden cardiac death (SCD). Predisposing factors included exercise, sudden startle or sleep. Only three patients showed familial histories of syncope or SCD. The average QTc interval was 0.58±0.05 second (range: 0.47-0.61 seconds). T wave morphologies were classified as normal-appearing, broad-based, low amplitude/bifid or late onset. For its management, bblockers were used in 7 patients. In 2 patients, whose clinical events were related with to an increased vagal tone or were aggravated by bblocker therapy, mexiletine was prescribed. When bradycardia or AV block was documented, pacemakers were implanted. For 2 patients at high risk of sudden cardiac death, cardioverter-defibrillators were implanted. During a mean follow up period of 23.5±20.2 months (range: 364 months), symptoms (cardiac arrest) recurred in 1 patient.

Congenital LQTS is a heterogeneous disease, showing diverse clinical manifestations, ECG features, and response to pharmacological management. Further research on the genotype-phenotype relationship will refine the management, enabling gene-specific treatment of this life-threatening disease.