BVT and Andersen-Tawil Syndrome. Bidirectional ventricular tachycardia (BVT), although a rare arrhythmia in the general population, is frequently observed in patients with Andersen-Tawil syndrome and long QT interval. However, the pharmacologic treatment of this arrhythmia remains unknown. In the present study, we documented the favorable antiarrhythmic action of flecainide in a young woman with sustained BVT and Andersen-Tawil syndrome. She presented with incessant BVT that could only be terminated with flecainide. During sinus rhythm, a prolonged QT interval was observed. Genetic studies revealed a mutation in the K + channel gene KCNJ2. Over a 4-year follow-up period, recurrence of her arrhythmia occurred twice. The first episode was due to noncompliance and resolved with resumption of flecainide therapy. The second recurrence was associated with a tachycardia-induced cardiomyopathy and resolved when the dose of flecainide was increased from 200 to 300 mg daily. This report suggests that flecainide can be effective in controlling BVT associated with Andersen-Tawil syndrome and indicates that the left ventricular dysfunction is secondary to the arrhythmia and not due to an associated phenotypic manifestation of the disorder. (J Cardiovasc Electrophysiol, Vol. 19, pp. 95-97, January 2008.) bidirectional ventricular tachycardia, long QT syndrome, Andersen-Tawil syndrome, flecainide Case Report A 16-year-old female was referred for evaluation of sustained bidirectional ventricular tachycardia (BVT) associated with dizziness. The patient had no known heart disease, was on no medications, and had no family history of heart disease or sudden death. Physical examination was normal except for mild symmetric lower extremity weakness. Serum laboratory assessments, chest x-ray, echocardiography, and cardiac magnetic resonance imaging were all normal. On admission, an electrocardiogram showed BVT with alternating QRS complexes (Fig. 1). Atrial and ventricular transesophageal stimulation failed to terminate the arrhythmia. Multiple drugs given intravenously were also unsuccessful, including lidocaine, propranolol, diltiazem, potassium chloride, and magnesium sulfate. Administration of oral flecainide 100 mg twice a day suppressed the arrhythmia and allowed resumption of sinus rhythm with a distinct long QT interval and biphasic T waves (Fig. 2). Genetic analysis demonstrated an R67W mutation in the K+ channel gene KCNJ2. The patient refused ICD implantation and was discharged on flecainide therapy. A complete cardiovascular evaluation of her parents and three brothers disclosed no abnormalities. During a 4-year follow-up period, the patient had two recurrences of BVT. The first episode was due to noncompliance and the arrhythmia disappeared when the patient resumed flecainide treatment. The second episode occurred 3 years later while on flecainide and was associated with congestive heart failure and globally depressed left ventricular function (ejection fraction 25%). The arrhythmia was controlled when the daily dose of...