The primary objective of this study is to determine if omega-3 polyunsaturated fatty acids reduce atrial fibrillation and other outcomes after cardiac surgery. In this placebo-controlled trial, patients undergoing elective coronary artery bypass graft surgery with or without valve repair will be treated with omega-3 polyunsaturated fatty acids perioperatively. The following hypotheses will be tested: 1. omega-3 polyunsaturated fatty acids reduces the incidence of atrial fibrillation (AF) after cardiac surgery, 2. omega-3 polyunsaturated fatty acids, administered in the perioperative period for cardiac surgery, decreases postoperative complication rates, and 3. omega-3 polyunsaturated fatty acids decrease intensive care unit and hospital length-of-stay.

Atrial fibrillation is the most common complication after bypass surgery. It is a significant burden to the healthcare system because it is associated with increased hospital costs and a longer hospital length-of-stay. Atrial fibrillation occurring after bypass surgery is associated with increased morbidity and mortality. Atrial fibrillation is also associated with an increased risk for strokes, use of potentially harmful drugs, and the need for pacemaker therapy.

This study is for patients who are undergoing elective bypass surgery. Patients who meet study criteria and who consent to participate in the study will be randomized to treatment with omega-3 fatty acids or matching corn oil placebo, prior to surgery. After surgery, treatment will continue until the primary endpoint, atrial fibrillation, is reached, or 14 days, whichever is first.

Inclusion Criteria:

• Age 18-85 years old.
• Elective coronary artery bypass (CABG) operation with or without concomitant valve surgery planned for at least 2 days after enrollment.
• Signed, documented informed consent prior to admission to the study.

Exclusion Criteria:

• Urgent or emergent bypass required to be performed <24 hrs after screening.
• Unstable angina, requiring intervention or CABG <24 hrs after screening.
• Decompensated congestive heart failure.
• Chronic, persistent atrial fibrillation - patient in atrial fibrillation at the time of screening or enrollment or scheduled for a maze procedure or pulmonary vein isolation at the time of surgery.
• Known sensitivity to Omacor (0mega-3 acid ethyl esters) and hypersensitivity to fish, fish products or corn oil.
• Patients requiring warfarin or Lovenox the 2 days prior to bypass surgery.
• Patients on Class I or III antiarrhythmic agents (quinidine, procainamide, disopyramide, flecainide, propafenone, moricizine, dofetilide, sotalol, amiodarone) or who have taken these drugs within 5 elimination half-lives of the drug (or within 2 months for amiodarone).
• Patients who are pregnant or nursing.
• Patients unable to provide/sign informed consent.
• Patients currently enrolled in another clinical trial without a 30 day washout period.
• Patients currently taking marine based omega-three fish oil supplements.

1 year