Study on myofibril of right atrium myocardium in Patients with atrial fibrillation and rheumatic heart disease

Backgrounds:It has been shown that atrial fibrillation is more seen in left atrium(LA)than in right atrium(RA)and atrial fibrillation is more seen in RA than in LA,However,the RA pathological mechanism of atrial fibrillation(AF)is still unknown.Objectives:To study the pathological hasis of right atrial atrial fibrillation in patients with rheumatic heart disease(RHD)with AF.Methods:Twenty—nine patients with mitral valve replacement of RHD were divided into AF group(n=13)and sinus rhythm (SR)group(n=16)according to chronic AF or not.There aren't significant statistical difference in clinical factors between two groups.During the operation of valve replacement,the samples of right atrial ap- pendages were taken and the qualitative and quantitative study were made by electron microscopy.Results: Volume density of myofibril in AF group and SR group were 36.1±10.66% VS 43.72±8.9%(P＜0.05), respectively.Conclusions:There were significant difference in the pathological change of right atrial my- ocardium between AF and SR with RHD.It was indicated that the changes should be the important patho- logical basis of RA fibrillation of AF patients with RHD.