Atrial fibrillation (AF) is a supra-ventricular tachyarrhythmia characterized by uncoordinated atrial activation with resultant deterioration in atrial mechanical function and often times irregular and rapid ventricular conduction. The ventricular rate is dependent on the conduction properties of the atrioventricular node, which can be influenced by vagal/sympathetic tone, medications, or disease of the atrioventricular node (Silverstein et al., 2012).