ABSTRACT
The relation between atrial fibrillation [AF] and some clinicopathological parameters has been studied by comparing two groups of patients with rheumatic mitral stenosis. Group I included 10 patients with sinus rhythm and group II included 10 patients with AF. Clinical, laboratory, electrocardiographic, radiologic and echocardiographic examinations were done for all patients. A biopsy from the left atrial appendage was taken from each patient during closed mitral commissurotomy to study the pathological changes in the left atrial wall using Masson Trichrome stain. The results of this study revealed a positive relation between AF and the age of the patient, the duration of the mitral valve disease, the left atrial size, the presence of tricuspid regurgitation, the amount of fibrosis, muscle atrophy and loss of muscle architecture in the left atrial wall. Meanwhile, AF has no relation to sex, severity of mitral stenosis, degree of pulmonary hypertension and presence of gradient across the mitral valve