Effect Of Thyroid Hormone On The Atrial Electrophysiology And Blood Coagulation In Canines

Objective: To investigate the effect of thyroid hormone on the electrophysiological characters of atrium, and the coagulation disorder in the hyperthyroidism and its mechanism. Our aim is to advance the effective therapies for atrial fibrillation (AF) in patients with hyperthyroidism and its blood vessel complications.Methods: A canine model of hyperthyroidism was established by daily intraperitoneal injection of L-Thy (80ug/kg per day, 8 months). 11 canines were divided into control group(n=6)and trail group(n=5) randomly. The atrial effective refractory period (ERP) was assessed every two months. Serum TT3 and TT4 were measured by radioimmunoassay. At the end of the follow-up period, all the canines underwent echocardiography and IVS, LVD, LAD, LVPW were measured. Both atrial and ventricular myocardium were collected at 8th month. Myocardium structure changes were detected by HE stain in light microscope. NO concentration of atrial and ventricular endocardium were measured by nitrate reductase technique. Expression of eNOS, PAI-1 protein in left atrial endocardium was evaluated with Western blot analysis. Protein eNOS was also localized by immunohistochemistry.Results: In the trial group, canines showed changed life habits, increased HR and serum TT3, TT4, reduced body weight. Atrial ERP has the tendency to be shorten, atrial tachyarrhythmia was induced in 3 canines of trial group. 2 canines were induced atrial tachycardia and atrial flutter in...