After cardiac or noncardiac surgery
Atrial fibrillation is common after open heart surgery, occurring in approximately 25% to 50% of patients.26–28
When this happens, at least one or two attempts are made to restore sinus rhythm. Especially in the early postoperative period, anticoagulation with heparin or warfarin may be contraindicated, so careful attention must be paid to the patient’s heart rhythm so that atrial fibrillation can be recognized quickly and cardioversion performed within a 48-hour window of onset. Beta-blockers, diltiazem, and verapamil are typically used for rate control.
When atrial fibrillation recurs in patients who have undergone open heart surgery, antiarrhythmics are started early to help prevent further recurrences. At our institution, we usually use amiodarone, as it is highly effective and well tolerated in the short term. When started on amiodarone for postoperative atrial fibrillation, patients are informed that the drug will be stopped after about 2 to 3 months. For patients who continue to have bouts of atrial fibrillation, the need for antiarrhythmic medications can be reassessed, and, if needed, the optimal antiarrhythmic medication for long-term therapy for the patient can be chosen.
Atrial fibrillation in severe, acute illness
Atrial fibrillation is common in the setting of extreme systemic stressors such as shock and sepsis and when the patient is being supported with inotropic agents. In this setting, patients may be in a high-catecholamine state, and both the heart rate and the heart rhythm may be very difficult to control.
Beta-blockers and nondihydropyridine calcium channel blockers should not be used when patients are on medications to support blood pressure, and in this setting, when the patient’s hemodynamic status permits the use of these agents, their effect may be minimal.
Amiodarone or perhaps digoxin may slow the heart rate somewhat without too much effect on the blood pressure. However, with amiodarone, one may have to accept a risk of chemical cardioversion.
Electrical cardioversion with or without the assistance of an antiarrhythmic drug may control the heart rate by restoring sinus rhythm. However, atrial fibrillation often recurs, and if it recurs quickly one may have to accept elevated heart rates until the underlying process is addressed.