The Mechanism On Sinus Rhythms Maintenance After Electric Cardioversion For Atrial Fibrillation In Patients With Rheumatic Valve Disease

Objective to explore the mechanism on sinus rhythms maintenance after electric cardioversion for atrial fibrillation in rheumatic heart disease patients by observing the changes of ultrstructures, myocyte diameter, the level of fibrosis, duration of AF and left atrium diameter. Methods 43 rheumatic valvular disease patients(31 patients with atrial fibrillation, 12 patients with sinus rhythm) underwent cardiac valve replacment. At time of surgery,parts of atrial myocardium were removed from the right auricle, and the tissues were examined by light and electron microscopy. According to the exent of ultrastructure changes, 31 patients with atrial fibrillation were divided into 3 groups:slightly changed group, moderately changed group and markly changed group. Patients with AF were underwent external direct-current cardioversion 4 weeks later. The affecting factors of sinus rhythm maintence in these patients with AF were observed during 6 months followed-up. Results (1) Compared with the sinus rhythm patients, A substantial proportion of the atrial myocytes of three group patients revealed marked changes in their cellular substructures, such as loss of myofibrils, accumulation of glycogen, changes in mitochondrial shape and size and dispersion of nuclear chromatin. There are remarkble diference of cardiac myocyte diameter and atrial fibrosis between patients with sinus rhythm and atrial fibillation. (2) Among 31 patients with AF, 6 patients spontanouslyconverted to sinus rhythm, and the others underwent external direct-current cardioversion. The result of followed-up showed that there were remarkable difference in three groups , and the changes of ultrastructure(P<0.05), myocyte diameter(P<0.05),the degree of fibrosis(P<0.05), duration of AF(P<0.01) and daimeter of left atrium(P<0.05) were associated with the maintence of sinus rhythm. Conclusion Compared with the sinus rhythm patients, there were various changes of ultrastructure, diameter of myocyte and atrium, fibrosis in the patients with AF.These factors may be the mechanisms which affect the maintence of sinus rhythm after cardioversion.Postgraduate Fan Guangci(Cardiology) Directed by Prof. Fan Zuowen...