Redefining the role of digoxin in the treatment of atrial fibrillation.

Atrial fibrillation (AF) encompasses a variety of discrete clinical syndromes, including paroxysmal, chronic, acute, and postoperative. Digoxin, long considered the mainstay of therapy for rate control in all types of AF, appears to have only modest electrophysiologic effects, which are mediated primarily by the autonomic nervous system. Digoxin has less potency than the calcium antagonists or beta-blocking drugs with respect to atrioventricular nodal blockade. Although less potent than calcium antagonists or beta-blocking drugs on the atrioventricular node, digoxin provides positive inotropic support, whereas the other 2 agents can suppress left ventricular function. Thus, digoxin is the agent of choice in patients with AF in the setting of significant left ventricular dysfunction. However, in the absence of left ventricular dysfunction, digoxin should be considered second-line therapy for the treatment of all AF syndromes.