Dietary fish oil and post surgical atrial fibrillation

INTERVENTION: Dietary fish oil or high monounsaturated sunflower oil commencing 3 weeks prior to surgery. If surgery is postponed after commencing the intervention, then treatment will continue until surgery. There is no maximum period of the intervention. the dose is 15 ml/day and is supplied as bulk liquid in 500 ml bottles. subjects are instructed to take the oil on juice CONDITION: Atrial fibrillation post cardiac surgery PRIMARY OUTCOME: Incidence of atrial fibrillation SECONDARY OUTCOME: • AF/AFL characteristics (incl. number of episodes, time to onset of first episode, mean and median duration of each episode, duration of longest episode, mean ventricular response rate during each episode of AF) ; • AF burden (total time in AF) ; • Mean heart rate ; • Atrial premature beat frequency • Association between HRV and post‐surgical AF/AFL • Association between hsCRP and atrial fibrillation. • Post‐operative complications including mortality ; • Length of stay (ICU and total) ; • Proportion of patients discharged within 6 post‐operative days. Effect of n‐3 fatty acids on adverse cardiac outcomes Effect of n‐3 fatty acids on measures of cardiac repolarisation and conduction INCLUSION CRITERIA: Elective coronary bypass surgery (CABG and/or valve repair/replacement surgery)• Informed consent