title: Functional role of myocardial electrical remodeling in diabetic rabbits.
abstract: The objective of the study was to investigate the role of electrical remodeling of the ventricular myocardium in hemodynamic impairment and the development of arrhythmogenic substrate. Experiments were conducted with 11 healthy and 12 diabetic (alloxan model, 4 weeks) rabbits. Left ventricular pressure was monitored and unipolar electrograms were recorded from 64 epicardial leads. Aortic banding was used to provoke arrhythmia. The diabetic rabbits had prolonged QTc, with activation-recovery intervals (surrogates for repolarization durations) being relatively short on the left ventricular base and long on the anterior apical portions of both ventricles (P < 0.05). In the diabetic rabbits, a negative correlation (-0.726 to -0.817) was observed between dP/dt(max), dP/dt(min), and repolarization dispersions. Under conditions of systolic overload (5 min), tachyarrhythmias were equally rare and the QTc and activation-recovery intervals were shortened in both groups (P < 0.05), whereas QRS was prolonged in the diabetic rabbits only. The repolarization shortening was more pronounced on the apex, which led to the development of apicobasal and interventricular end of repolarization gradients in the healthy animals, and to the flattening of the repolarization profile in the diabetic group. Thus, the diabetes-related pattern of ventricular repolarization was associated with inotropic and lusitropic impairment of the cardiac pump function.
authors: Laboratory of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 50 Pervomayskaya Street, 167982 Syktyvkar, Russia., First Department of Internal Diseases of Komi Branch of Kirov State Medical Academy, 11 Babushkin Street, Syktyvkar 167000, Russia., Department of Physiology, Medical Institute of Syktyvkar State University, 11 Babushkin Street, Syktyvkar 167000, Russia.
authors: Alexey O
authors: AO
authors: Ovechkin
authors: Marina A
authors: MA
authors: Vaykshnorayte
authors: Ksenia
authors: K
authors: Sedova
authors: Konstantin V
authors: KV
authors: Shumikhin
authors: Natalia V
authors: NV
authors: Arteyeva
authors: Jan E
authors: JE
authors: Azarov
mesh_terms: D000496:Alloxan / Q000633:toxicity; D000818:Animals; D017849:Animals, Inbred Strains; D001145:Arrhythmias, Cardiac / Q000209:etiology; D003922:Diabetes Mellitus, Type 1 / Q000139:chemically induced / Q000150:complications*; D058065:Diabetic Cardiomyopathies / Q000473:pathology / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006352:Heart Ventricles / Q000294:innervation* / Q000473:pathology / Q000503:physiopathology; D009929:Organ Size; D011817:Rabbits; D018754:Ventricular Dysfunction / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D020257:Ventricular Remodeling
chemical_list: D000496:Alloxan
keywords: activation–recovery intervals; arrhythmias; arythmie; inotropie; inotropy; intervalles d’activation–récupération; lusitropie; lusitropy; repolarisation; repolarization