FISHing for Answers in Postoperative Atrial Fibrillation

D ietary fish intake and ingestion of omega-3 polyunsatu-rated fatty acids (n3-PUFAs) have been associated with lower rates of ventricular and atrial arrhythmias in some (but not all) observational studies and randomized controlled clin-ical trials performed on diverse human populations.1,2 These findings have sparked detailed investigations to identify the potential antiarrhythmic mechanisms. In vitro studies have shown that n3-PUFAs affect cellular membrane properties, ion channels and exchangers, nuclear receptors, transcription factors, kinases, and inflammatory mediators. In vivo studies have identified potential antiarrhythmic effects from short- and long-term treatment with n3-PUFAs in small and large animal models.3–5 Several single-center studies have examined whether n3-PUFA treatment decreases the incidence of atrial fibrillation (AF) after cardiac surgery (Table 1).6 In an open-label study in 2005, Calo ̀ et al7 reported a 64 % decrease in postoper-ative AF in patients treated with 1.7 to 1.8 g/d of docosa-hexaenoic acid / eicosapentaenoic acid given 5 days preop-eratively through discharge versus those treated with usual care (n=160, P=0.01). Three other double-blind, placebo-controlled studies in which 2.0 to 4.6 g/d of docosahexaenoic acid / eicosapentaenoic acid was started 5 to 21 days before the operation and continued until discharge reported no dif