Arrhythmias especially in presence of hypokalemia, lack of mortality benefit. However, their efficacy in reducing the symptoms of heart failure has been established. Digoxin should be used for patients who remain symptomatic when diuretics and ACE inhibitors as well as for heart failure patients who are in atrial fibrillation and require rate control. In most patients with chronic heart failure it is sufficient to begin with the expected maintenance dose (usually 0.125-0.25 mg daily). Most of the positive inotropic effect is apparent with serum digoxin levels between 0.7 and 1.2 ng/ml, and levels above this range may be associated with a higher risk of arrhythmias and lower survival rates, though clinically evident toxicity is rare with levels below 1.8 ng/ml.