Abstract: Objective　To investigate the effect of glyburide (GLB) on the induction of atrial remodeling and atrial fibrillation (AF) in diabetes mellitus (DM) rats. Methods　Forty-eight SD rats were randomly divided into the three groups: the control group (Ctl group), the diabetes group (DM group) and the diabetes + GLB group (GLB group), with 16 rats in each group. The DM animal model was established by streptozotocin method, and the GLB group was given GLB (10 mg/kg) daily by gavage. The animals were fed under the same conditions for 6 weeks, and fasting blood glucose and body weight were recorded at the sixth weeks. The early diastolic peak velocity (E), late diastolic peak velocity (A), left atrial diameter, ejection fraction, left ventricular short axis shortening rate, E/A, pulmonary artery flow acceleration time, mean pulmonary artery pressure, systolic and diastolic ventricular septum, left ventricular diameter and left ventricular posterior wall thickness were measured by cardiac ultrasound 6 weeks later. Heart rate, systolic blood pressure, diastolic blood pressure and mean arterial blood pressure were measured. The atrioventricular, wenckebach cyclelength, recovery time of sinoatrial node, effective refractory period and AF induction rate of rats were measured by electrophysiological experiment. Epicardial activation mapping experiment was used to detect absolute inhomogeneity index, conduction heterogeneity and epicardial conduction velocity. Masson staining was used to detect left atrium fibrosis, and collagen volume fraction (CVF) was calculated. Results　Compared with the DM group, lower heart body mass ratio and ventricular body mass ratio, lower left atrial inner diameter were found in the GLB group (P＜0.05). Compared with the Ctl group, the epicardial conduction velocity was decreased and the relative conduction heterogeneity was increased in the DM group. Compared with the DM group, epicardial conduction velocity was increased in the GLB group (P＜0.05), and there was no significant difference in conduction relative heterogeneity. Compared with the DM group, the GLB group had shorter R-R interval and lower AF induction rate (P＜0.05). Compared with the Ctl group, the degree of atrial muscle fibrosis was worse and CVF increased in the GLB and the DM groups (P＜0.05). Conclusion　DM can promote atrial fibrosis in rats, which is correlated with the incidence of AF. GLB can reduce the induction rate of AF by delaying the progression of myocardial fibrosis in DM rats.

Key words: atrial fibrillation, diabetes mellitus, Glyburide, atrial remodeling, myocardial fibrosis