title: Ventricular repolarization in a rat model of global heart failure.
abstract: Isoproterenol in high doses induces infarction-like myocardial damage and structural and functional remodelling of the ventricular myocardium. The purpose of the present study was to investigate ventricular repolarization in a rat model of isoproterenol-induced heart failure. Isoproterenol was administered twice to female Wistar rats (170 mg/kg, s.c., 24 h apart). Four weeks after the injections, cardiac output was measured and unipolar epicardial ventricular electrograms were recorded in situ. Activation-recovery intervals were calculated to assess repolarization. Histological examination of the heart ventricles was also performed. Heart failure in rats treated with isoproterenol was indicated by myocardial histopathological damage and reduced cardiac output. In rats with heart failure, the regional differences in activation-recovery interval prolongation over the ventricular epicardium resulted in increasing heterogeneity in the activation-recovery interval distribution and increasing repolarization heterogeneity of the ventricular subepicardium. Myocardial damage and haemodynamic changes in heart failure induced by isoproterenol were accompanied by significant changes in ventricular repolarization, which were not associated with myocardial hypertrophy.
authors: Laboratory of Cardiac Physiology, Institute of Physiology of the Komi Science Centre of the Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia.
authors: Valeria
authors: V
authors: Krandycheva
authors: Sergey
authors: S
authors: Kharin
authors: Marina
authors: M
authors: Strelkova
authors: Konstantin
authors: K
authors: Shumikhin
authors: Aleksey
authors: A
authors: Sobolev
authors: Dmitry
authors: D
authors: Shmakov
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002302:Cardiac Output / Q000187:drug effects / Q000502:physiology; D004195:Disease Models, Animal; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006352:Heart Ventricles / Q000187:drug effects / Q000503:physiopathology*; D006984:Hypertrophy / Q000503:physiopathology; D007545:Isoproterenol / Q000494:pharmacology; D009206:Myocardium / Q000473:pathology; D010496:Pericardium / Q000187:drug effects / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007545:Isoproterenol