Role of Digoxin in Atrial Fibrillation
Since its isolation in the 1930s, digoxin has played a pivotal role in the treatment of cardiac conditions including heart failure and supraventricular tachyarrhythmias. The parasympathomimetic activity makes digoxin a reasonable option for controlling ventricular rate in atrial fibrillation (AF). However, the unique pharmacokinetic properties, electrolyte-dependent effects, and P-glycoprotein drug interactions influence the clinical use of digoxin. In addition, the delayed onset and narrow therapeutic index can make digoxin utilization cumbersome and often necessitates serum drug monitoring. Despite digoxin’s extensive history, recent literature has cast doubt on the efficacy and safety of this medication in the population with AF. Large amounts of data suggest digoxin offers no benefit on mortality and may increase the risk of mortality though this was not consistent in all evaluations. While robust, the majority of the available studies are not randomized which limits the ability to draw firm conclusions. The potential risk of mortality must be weighed against the expected benefits of digoxin use to make individualized patient care decisions. Clinicians should refrain from utilizing digoxin monotherapy for rate control in AF when other options are viable.