A large body of evidence has accumulated showing that n-3 PUFAs exert extensive cardiac effects. The development of commercial solutions of FO opens perspectives for therapeutic applications in patients with acute cardiac conditions.the 3 following hypotheses will be addressed in patients requiring cardiac surgery under cardiopulmonary bypass or after myocardial infarction:perioperative /post-PTCA intravenous fish oil modifies the composition of membrane phospholipids in platelets and cardiac cells, blunts the physiological response to cardiac surgery/myocardial infarction, and reduces the incidence of arrhythmias, and reduces the occurrence of systolic dysfunction.