Abstract
The Andersen-Tawil syndrome (ATS) is a disease entity characterized by 3 features: (1) ventricular arrhythmias with U waves, (2) periodic paralysis, and (3) dysmorphic features. The cause of ATS is mutations in KCNJ2, the gene encoding an inward rectifier potassium channel (Kir2.1). Electrocardiogram (ECG) manifestations of ATS include prominent U waves with QU prolongation, frequent premature ventricular contractions (PVCs), and bidirectional ventricular tachycardia (biVT). Previous case reports have demonstrated that flecainide is effective in VT suppression. Our patient was a 50-year-old woman who showed the three typical features of ATS. Genetic testing revealed a mutation in KCNJ2 (R218W). Her ECG showed a typical U wave with QU prolongation (723 ms) and frequent multifocal PVCs. In 24-hour Holter ECG, PVCs were 24% of the total QRS, and typical biVT was detected. After flecainide therapy (100 mg/day), the number of PVCs was reduced to 9%. Her palpitation was improved. Prominent U waves and biVT are key findings in ATS. Therefore, in ECG analysis, it is important to provide information on the QU interval, U wave amplitude, U wave duration, and polarity of PVCs.
