We suggest that patients who have a contraindication to &beta;-blocker therapy and to amiodarone therapy before or after cardiac surgery be considered for prophylactic therapy to prevent postoperative AF with either:<br /><ul><li>intravenous magnesium, or; (Recommendation Conditional, Quality Moderate)</li><li>with biatrial pacing. (Recommendation Conditional, Quality Low)</li></ul><br /><br /><b>Values and preferences: </b>This recommendation places a high value on preventing postoperative AF using more novel therapies that are supported by lower quality data. A high value is placed on the low probability of adverse effects from magnesium. The use of biatrial pacing needs to be individualized by patient and institution, as the potential for adverse effects may outweigh potential benefit based on local expertise.