Extracellular electrograms, recorded directly from the heart, are the hallmarks of invasive cardiac electrophysiology and provide information about the electric status of the underlying myocardium. These electrograms are generated by depolarization of cardiomyocytes that generates transmembrane currents in extracellular space and potential differences due to electric resistance of the extracell...

Objective(s): In this study, the neutralizing abilities of the equine and the recently introduced camelid antivenoms on the hemodynamic parameters (inotropism, chronotropism, and arrhythmogenicity) were assessed following envenomation by Hemiscorpius lepturus venom in rats. Materials and Methods: At first, the electrophoretic profiles of...

Abstract Background Hypertrophic cardiomyopathy (HCM) is the commonest inherited cardiac disease, with a prevalence of 1/500 in general population. The most devastating consequence HCM sudden death (SCD) due to ventricular fibrillation, particularly common children and young adults (age <30 years). positive correlation between extent late gadolinium enhancement (LGE, reflecting myocardia...

Although regular exercise training is associated with cardiovascular benefits, the increased risk of atrial arrhythmias has been observed after vigorous and related to oxidative stress. We aimed at investigating exercise-induced remodeling in a rat model an athlete’s heart determining sex-specific differences. Age-matched young adult rats were divided into female exercised, control, male contro...

In October 2008, in a public forum organized by the Cardiac Safety Research Consortium and the Health and Environmental Sciences Institute, leaders from government, the pharmaceutical industry, and academia convened in Bethesda, MD, to discuss current challenges in evaluation of short- and long-term cardiovascular safety during drug development. The current paradigm for premarket evaluation of ...

To evaluate autonomic influence on arrhythmogenesis in an animal preparation of triggered activity, we gave increasing doses of cesium chloride (0.125 to 5.0 mmol/kg iv) to 24 dogs distributed equally among four protocols of autonomic intervention: control, total denervation, beta-blockade, and left stellate stimulation. All dogs underwent atrioventricular node ablation followed by ventricular ...

RATIONALE Remodeling of connexin (Cx)43 gap junctions (GJs) is linked to ventricular arrhythmia. OBJECTIVES A peptide mimetic of the carboxyl terminal (CT) of Cx43, incorporating a postsynaptic density-95/disks-large/ZO-1 (PDZ)-binding domain, reduces Cx43/ZO-1 interaction and GJ size remodeling in vitro. Here, we determined: (1) whether the Cx43-CT mimetic αCT1 altered GJ remodeling followin...

Purkinje cells (Pcell) are characterized by different electrophysiological properties and Ca cycling processes than ventricular myocytes (Vcell) and are frequently involved in ventricular arrhythmias. Yet, the mechanistic basis for their arrhythmic vulnerability is not completely understood. The objectives were to: (1) characterize Pcell electrophysiology, Ca cycling, and their rate dependence;...

RATIONALE Calmodulin (CaM) mutations are associated with an autosomal dominant syndrome of ventricular arrhythmia and sudden death that can present with divergent clinical features of catecholaminergic polymorphic ventricular tachycardia (CPVT) or long QT syndrome (LQTS). CaM binds to and inhibits ryanodine receptor (RyR2) Ca release channels in the heart, but whether arrhythmogenic CaM mutants...

In order to evaluate the arrhythmogenic potency of macrolide antibiotics in a quantitative manner, we analyzed the influence of clarithromycin (CAM), roxithromycin (RXM), and azithromycin (AZM) on Q-T intervals from pharmacokinetic and pharmacodynamic points of view and in comparison with the potency of erythromycin (EM) previously reported by us for rats. Male Sprague-Dawley rats were anesthet...