Changing Levels Of Myocardial Cell Apoptosis After Atrial Fibrillation Converted To Sinus Rhythm In A Goat Model

Objective:To investigate the changing levels of myocardial cell apoptosis after chronic atrial fibrillation(AF)conversion to sinus rhythm and to explore the association between the atrial reverse remodeling and the myocardial cell apoptosisMethods:Eighteen goats were randomly divided into three groups(each n=6):(A)sinus rhythm(SR),(B)Chronic AF,(C)sinus rhythm after AF.All the goats in each group were underwent open chest surgery to implant the pacemaker electrode into left appendages.Group B and C were given continuous and rapid pacing (400±10 bpm)in order to build chronic AF model.Goats in group A were killed after three months without pacing.Goats in group B were killed three months after atrial rapid pacing. In group C,pacing was stopped and sinus rhythm was aquired by propafenone and/or direct current cardioversion.After three months' maintenance of sinus rhythm,goats were killed. The atrial tissue was obtained from the left atrium and was stained by EdUTP-in situ end-labeling and observed by flow cytometry.Results:The apoptotic ratio of the left atrial myocytes in the goats with chronic AF was significantly higher than that in the goats with sinus rhythm(P＜0.05).It was still higher in the goats with 3 months' maintenance of SR post-AF than that in the goats with sinus rhythm(P＜0.05),but lower than that with chronic AF(P＜0.05).Conclusions:The changing levels of myocardial cell apoptosis before and after AF conversion suggests that myocardial cell apoptosis is associated with atrial remodeling and reverse remodeling.