Mexiletine effectively prevented refractory Torsades de Pointes and ventricular fibrillation in a patient with congenital type 2 long QT syndrome

We report a 28-year-old female patient with congenital type 2 long QT syndrome (LQTS) in which mexiletine shortened corrected QT interval (QTc) and effectively prevented refractory Torsade de Pointes (TdP) and ventricular fibrillation (VF). She developed TdP and VF, and was subsequently diagnosed with congenital type 2 LQTS. She had refractory TdP and VF every day despite medical therapy including β-blocker. They were completely suppressed after the initiation of mexiletine with shorting of QTc interval.