adult patients undergoing any cardiac surgical procedure with the use of cardiopulmonary bypass

a history of ecg-documented atrial fibrillation with prior stroke or tia, or at least two of the following risk factors:

age => 65 years

hypertension

diabetes mellitus, or

heart failure/left ventricular ejection fraction < 50%

patients in whom surgical af ablation (maze or otherwise) is planned

planned "off-pump" surgery

planned implantation of a mechanical valve

heart transplant, complex congenital heart surgery, and ventricular assist device insertion, reoperation