Amiodarone for atrial fibrillation following cardiac surgery: development of clinical practice guidelines at a university hospital

Abstract

Atrial fibrillation (AF) usually develops within the first 72 h following cardiac surgery, and is often self-limiting. Within 48 h of acute onset of symptoms, approximately 50% of patients spontaneously convert to normal sinus rhythm. Thus, the relative risks and benefits of therapy must be carefully considered. The etiology of AF following cardiac surgery is similar to that in non-surgical patients except that pericardial inflammation and increased adrenergic tone play an increasingly important role. Further, AF after surgery may be associated with transient risk factors that resolve as the patient moves out from surgery, and the condition is less likely to recur compared to AF arising in other circumstances. Immediate heart rate control is important in preventing ischemia, tachycardia-induced cardiomyopathy, and left ventricular dilatation. At our institution, amiodarone is frequently used as a first-line drug for treating AF after cardiac surgery. Inconsistent prescribing practices, variable dosage regimens, and a lack of consensus regarding the appropriate use of amiodarone prompted the need for developing practice guidelines. Multidisciplinary collaboration between the departments of cardiac surgery, pharmacy, and anesthesiology led to the development of a protocol for postoperative AF. We review the clinical evidence from published trials and discuss our guidelines, defining amiodarone use for AF in the cardiac surgery setting.