Abstract: Objective: To explore the role of docosahexaenoic acid(DHA) in atrial fibrillation rat,and its effects on the expression of TWIK-Related K⁺ Channel 1(TREK-1).Methods: Sprague-Dawley(SD) rats sensitive to acetylcholine-calcium chloride mixture were randomly divided into the control group(group A),DHA treatment control group(group B),atrial fibrillation(group C) and DHA treatment atrial fibrillation group(group D).The duration of atrial fibrillation and atrial effective refractory period(ERP) were observed.The expressions of TREK-1 protein and mRNA in atrial muscle of rats were detected using Western blot and reverse transcriptase-polymerase chain reaction.Results: Compared with group C,the occurrence and duration time of atrial fibrillation in group D were significantly delayed and shorten,respectively(P<0.01).Compared with group A and D,the atrial ERP in group C was significantly shorten(P<0.01).Compared with group A and D,the expressions of TREK-1 mRNA and protein in group C increased significantly(P<0.01).Conclusions: DHA may play the role of anti-atrial fibrillation,the mechanism of which may be related to the expression downregulation of TREK-1.