Atrial fibrillation : The ventricular rate in atrial fibrillation can be controlled with a beta-blocker or diltiazem.or verapamil. Digoxin is usually effective for controlling the rate at rest; it is also appropriate if atrial fibrillation is accompanied by congestive heart failure. If the rate at rest or during exercise cannot be controlled, diltiazem or verapamil may be combined with digoxin, but care is required if the ventricular function is diminished. In some cases, e.g. acute atrial fibrillation or paroxysmal atrial fibrillation, diltiazem or verapamil or a beta-blocker may be more appropriate than digoxin (see also Paroxysmal Supraventricular Tachycardia and Supraventricular Arrhythmias below). Anticoagulants are indicated especially in valvular or myocardial disease, and in the elderly; in the very elderly the overall benefit and risk needs careful assessment. Younger patients with lone atrial fibrillation in the absence of heart disease probably do not need anticoagulation. Aspirin is less effect than warfarin at preventing emboli but may be appropriate if there are no other risk factors for stroke; aspirin 75 mg may be used.