HEART FAILURE: Digoxin therapy has no effect on mortality in heart failure. Digoxin may be useful for maintaining clinical stability and exercise capacity in patients with symptomatic heart failure. Digoxin appears to be of most benefit in patients with severe heart failure, cardiomegaly and a third heart sound. Digoxin should be used as a second-line drug after diuretics, angiotensin-converting enzyme inhibitors and beta-blockers in patients with congestive heart failure who are in sinus rhythm. Digoxin should be used as a first-line drug in patients with congestive heart failure who are in atrial fibrillation. ARRHYTHMIAS: Digoxin has a limited, but useful, role, either alone or in combination with other agents such as beta-blockers, diltiazem or verapamil, in achieving satisfactory resting ventricular rate control in patients with chronic atrial fibrillation. In patients who lead a predominantly sedentary lifestyle (perhaps particularly in those who are elderly), digoxin alone may be the agent of choice.