The problem of atrial arrhythmias after noncardiac thoracic surgery.

Perhaps because of effective antiarrhythmic medications that can be used to treat patients with postoperative AF, these arrhythmias were often thought to be benign, producing only transient discomfort, palpitations, or shortness of breath. For patients undergoing cardiac surgery, we now have substantial evidence that postoperative AF is associated with increases in the use of hospital resources, length of hospital stay, and hospital costs. Moreover, postoperative AF has been associated with a variety of other adverse outcomes, including perioperative myocardial infarction, congestive heart failure (CHF), ventricular arrhythmias, renal insufficiency, infection, pneumonia, increased need for inotropic medications, increased use of the intra-aortic balloon pump, prolonged ventilation, increased frequency of reintubation for respiratory distress, increased need for readmission to the intensive care unit, and increased need for tracheostomy. There is a growing recognition that one of the most important clinical consequences of postoperative AF might be an increased incidence of perioperative stroke. We have also come to recognize that these arrhythmias might be persistent or recurrent, even long after discharge from the hospital. Clinical investigation in adults undergoing cardiac surgery has focused mainly on 2 fronts: (1) the identification of risk factors for the development of postoperative AF and (2) various strategies for prophylaxis. The most commonly identified risk factors in retrospective studies are a previous history of atrial arrhythmias and increasing patient age. Other risk factors that have been reported include valvular heart disease, male sex, chronic obstructive pulmonary disease, the presence of right coronary artery stenosis, left ventricular hypertrophy, CHF, and various electrolyte abnormalities. Many investigators have suggested that patients who could be identified at high risk for this complication prospectively might benefit from prophylaxis strategies. It is important to remember that because postoperative AF occurs in only the minority of patients, many patients must be treated to prevent this complication in just the minority. As a result, prophylaxis strategies should come at low risk and (relatively) low cost. Prospective randomized trials have examined the utility of a variety pharmacologic agents used prophylactically, including -blockers, sotalol, amiodarone, verapamil, diltiazem, magnesium, digoxin, dexamethasone, glucose-insulinpotassium infusions, tri-iodothyronine, procainamide, alinidine, and quinidine. The results have often been conflicting, and as a result, there is no consensus. Most authorities would agree that the use of -blockers postoperatively can serve as effective prophylaxis. The evidence also suggests that amiodarone or sotalol, when used appropriately, can reduce the incidence of postoperative AF in adults undergoing cardiac surgery. Evidence from prospective randomized trials also suggests that the use of mild (rather than moderate) hyothermia, posterior pericardiotomy, atrial pacing, and heparin-coated cardiopulmonary bypass circuits might help to reduce the incidence of postoperative AF. From the University of Mississippi Medical Center, Jackson, Miss.