Oral verapamil effectively suppressed complex ventricular arrhythmias and unmasked U waves in a patient with Andersen-Tawil syndrome.

Andersen-Tawil syndrome (ATS) is a rare, heterogeneous, autosomal dominant, or sporadic disorder characterized by the clinical triad of periodic paralysis, dysmorphic features, and ventricular arrhythmias such as bidirectional ventricular tachycardia (BVT). We present a case of an elderly patient with ATS whose symptomatic ventricular arrhythmias including BVT were effectively suppressed by oral verapamil therapy.