RecruitingPhase 4Drug trialPharmacogenetic Study of Antiarrhythmic Drugs for Atrial FibrillationIn this pilot and feasibility study, the investigators will enroll patients with frequent symptomatic episodes of atrial fibrillation (AF) in a cross-over study testing two different classes of anti arrhythmic drugs (AADs). This pilot and feasibility study will provide preliminary data for a larger study in which the investigators will test the hypothesis that a common AF genetic risk allele modulates response to different AADs.