Flecainide-induced atrial flutter with 1:1 conduction complicated by ventricular fibrillation after electrical cardioversion

Abstract

Flecainide, a widely prescribed class IC agent used to treat atrial arrhythmias, can in rare cases cause 1:1 atrial flutter with rapid conduction. We describe the case of a 59-year-old man who was on a maintenance regimen of flecainide for refractory atrial fibrillation. When 1:1 atrial flutter with rapid conduction developed, emergency medical technicians attempted synchronized cardioversion, which caused ventricular fibrillation necessitating defibrillation. The patient ultimately underwent radiofrequency ablation and cryoablation to resolve his symptomatic atrial flutter. We discuss the atrial proarrhythmic effects of flecainide and how to mitigate complications in high-risk patients. (Tex Heart Inst J 2021;48(2):e197099).