Atrial Fibrillation After Cardiac Surgery: An Evidence-Based Approach to Prevention

minority of patients will develop AF. Thus, many patients will be exposed to potential side effects of a treatment when they are at low risk of developing AF. Pharmacologic Prevention Virtually all drugs from every Vaughan-Williams class of antiarrhythmics have been investigated as a means to prevent AF after cardiac surgery. Most trials that have explored class I agents (eg, procainamide, flecainide, and others) have limitations that impede firm conclusions to be drawn about safety and efficacy. 5 In light of the association of these drugs with proarrhythmia in patients with structural heart disease, the use of class I agents for the prevention of AF has not been recently pursued. More attention has been focused on drugs that possess β-blocking properties. Conventional β-Blockers Given the perceived role of heightened sympathetic tone in the development of postoperative AF, there has been great interest in the use of prophylactic β-blockers for patients undergoing cardiac surgery. Multiple trials have consistently shown that β-blockers effectively reduce the frequency of postoperative AF compared with placebo. 9,10 In a recent meta-analysis, β-blockers reduced the frequency of AF from 33% to 19% but with considerable heterogeneity between the trials. 11 These results appear to apply to all formulations, suggesting a class effect. Even when ineffective, the heart rate will be better controlled for patients developing AF when β-blockers are given. Thus, the available data suggest that β-blockers are effective in reducing the frequency of AF after cardiac surgery. Despite the prevalent efficacy data, limitations are common with trials of β-blockers for AF prophylaxis. For example, the trials vary in the use of intermittent electrocardiogram (ECG) monitoring versus continuous ECG monitoring. A di-P ostoperative atrial fibrillation (AF) occurs in 25% to 40% of patients after cardiac surgery. This arrhythmia has been associated with a more complicated postoperative course, increased risk of stroke, increased length of hospital stay, and increased hospital costs. This article focuses primarily on the various options available for the prevention of AF postcardiac surgery. The viewpoint developed is based on a critical assessment of whether existing data provide evidence that a given strategy is effective and safe for widespread implementation. The latter critique is important, given that only a A number of advances in surgical and anesthetic techniques have reduced the risk for patients undergoing cardiac surgery. However, postoperative atrial fibrillation remains common, with an incidence ranging between 25% and 40%. It is associated with an increased incidence of congestive heart failure, renal insufficiency, and stroke that prolongs hospitalization and increases rates of readmission after discharge. Consequently, there has been great interest in strategies to prevent this arrhythmia. When both safety and efficacy are considered, the available evidence to date suggests that only β-blockers can be recommended for the prevention of atrial fibrillation after cardiac surgery. Other treatments might be considered on an individual basis after careful consideration of the patient's potential for side effects