Pharmacotherapy of Atrial Fibrillation

Abstract

Atrial fibrillation is a common medical problem that has a wide clinical spectrum ranging from a benign condition, such as “lone” atrial fibrillation, to a life‐threatening arrhythmia, when there is an accessory pathway. There is a striking contrast between the frequency of atrial fibrillation and the absence of well‐defined, scientifically based medical management. At least four considerations guide the pharmacological treatment of patients with atrial fibrillation: (1) restoration of sinus rhythm; (2) acute and long‐term control of the ventricular rate; (3) maintenance of sinus rhythm; and (4) anticoagulation. Pharmacological cardioversion is best achieved with intravenous flecainide, intravenous propafenone, or intravenous ibutilide. During episodes of atrial fibrillation, the drugs of first choice for control of the ventricular rate are calcium antagonists and beta‐blockers. Digitalis is helpful in elderly patients and in cases with congestive heart failure. Maintenance of sinus rhythm is a complex task, owing to the proarrhythmic potential of antiarrhythmic drugs, and the treatment should be tailored to the individual patient's needs. No one drug is clearly better than another. As for amiodarone, its benefit/risk ratio remains to be evaluated prospectively. Usually, most of the patients benefit from serial electrical cardioversion, with the longest possible interval between cardioversion sessions being sought. The question about whether the aim of the treatment of atrial fibrillation should be to control the ventricular rate or to restore sinus rhythm will be answered by ongoing trials. The effectiveness of low‐dose anticoagulation in preventing stroke in patients with nonrheumatic atrial fibrillation has been validated by seven separate studies. Anticoagulation with warfarin should be monitored carefully in order to achieve an International Normalized Ratio (INR) of between 2.0 and 3.0. This targeted INR decreases the embolic rate and eliminates the risk of intracranial bleeding. The role of aspirin alone in decreasing the risk of stroke remains to be established. Pharmacological management of patients with atrial fibrillation has to be improved, by better risk stratification and the development of new drugs with an optimal benefit/risk ratio. Ongoing trials are expected to provide important guidelines, corresponding to the needs of the many different types of patients with atrial fibrillation.