Torsade-de-pointes in a patient under flecainide treatment, an unusual case of proarrhythmicity

Flecainide is an antiarrhythmic considered safe in patients who have no structural cardiopathy, and frequently used in the prevention of atrial fibrillation. However, in patients with a history of infarction and/or severe conduction disorders, its proarrhythmicity may be lethal. Torsade-de-pointes type tachycardia is not included as one of these proarrhythmic effects, since the drug's scant action on ventricular repolarization makes this adverse effect very unlikely. We present the case of a patient who, shortly after beginning treatment with flecainide, was admitted because of syncope related to bradyarrhythmias, long QT, and torsade-de-pointes. There have been very few published cases in which one finds such an association between flecainide and this infrequent arrhythmia.