Pharmacological management of atrial fibrillation following cardiac surgery

Atrial fibrillation (AF) is the most common complication following coronary artery bypass graft surgery (CABG). Post-CABG AF occurs most commonly on the second postoperative day and declines in incidence thereafter. A number of risk factors have been found to be associated with a higher frequency of post-CABG AF. These risk factors include advanced age, a prior history of AF, hypertension, and heart failure. Postoperative complications--including low cardiac output, use of an intra-aortic balloon pump, pneumonia, and prolonged mechanical ventilation--are also associated with higher rates of post-CABG AF. Post-CABG AF increases the risk of stroke, and the length and cost of hospitalization. Prophylactic administration of conventional beta-adrenoceptor antagonists (beta-blockers) or sotalol produces a consistent and significant reduction in the incidence of post-CABG AF; however, results with prophylactic amiodarone or magnesium are less consistent. Termination of post-CABG AF, once it occurs, can be accomplished with a number of antiarrhythmic agents. Ibutilide has been the most widely studied agent for this indication. Sotalol is not indicated for cardioversion of AF and has not been studied in the post-CABG setting. Electrical cardioversion and biatrial pacing have also been used to terminate post-CABG AF. Ventricular rate is best controlled with beta-blockers and calcium channel antagonists. Esmolol has a rapid onset of action and is easily titrated to effect. Digoxin can control the ventricular rate, but has a slow onset of action. There are limited data available to guide decisions regarding the optimal management of post-CABG AF.