New Guidelines for Postoperative Atrial Fibrillation: Key Points for Pharmacists

The American Association for Thoracic Surgery recently published new recommendations for the prevention and management of atrial fibrillation (AF) and flutter in patients undergoing thoracic surgery.

Postoperative atrial fibrillation (POAF) is associated with an increased risk of neurologic events, mortality, and resource use. A patient’s risk of developing new-onset POAF peaks 2 to 4 days following his or her surgery, although most cases (90% to 98%) resolve within 4 to 6 weeks. During the postoperative period, it is important to manage POAF appropriately through rate control, rhythm control, or anticoagulation in order to reduce the risk of adverse events.

After accounting for potential causes and assessing electrolyte disturbances, fluid status, and catecholamine use, POAF patients should be assessed for hemodynamic stability. Patients may be classified as hemodynamically unstable if they have severe hypotension, ischemia, or pulmonary edema, or previously experienced an acute myocardial infarction.

In hemodynamically unstable patients with POAF that persists for more than 48 hours, anticoagulation should be administered and continued for a minimum of 4 weeks. In hemodynamically unstable patients with POAF lasting 48 hours or less, direct current (DC) cardioversion may be considered. If DC cardioversion fails, triggering causes should be reconsidered, and pharmacologic rate or rhythm control may be instituted through intravenous (IV) amiodarone, esmolol, metoprolol, diltiazem, or digoxin.

The choice of medication for hemodynamically stable patients with POAF of any duration should be guided by the best available evidence and present comorbidities. For instance:

• In patients with heart failure or left ventricular dysfunction, IV esmolol is the preferred medication.
• In patients with hypotension, either IV esmolol or diltiazem may be used, depending on the degree of hypotension.
• In patients with COPD or asthma, either IV diltiazem or verapamil may be used.
• IV amiodarone is a possible alternative, albeit with a slightly lower level of evidence.
• IV digoxin is an alternative to amiodarone, but only in those without COPD or asthma.

It is important for pharmacists to safeguard against common medication errors in the postoperative period among patients who develop POAF, which include:

• Use of cumulative doses of amiodarone >2150 mg/m² of body surface area
• Use of IV flecainide or IV propafenone in patients with structural heart disease in patients undergoing pharmacologic cardioversion
• Use of new oral anticoagulants in patients with a mechanical heart valve
• Use of dronedarone in patients with heart failure who develop POAF
• Use of digoxin presurgically to prevent POAF