Introduction: Recent studies showed that nitrergic system have specific modulatory effects on electrophysiological properties of atrioventricular (AV) node. The aim of this study was to determine the effects of nitric oxide (NO) on the electrophysiological properties of isolated rabbit AV node and to investigate the role of adrenergic and cholinergic receptors in the mechanism of its action...

BACKGROUND Longitudinal dissociation of an anatomic pathway into 2 electrophysiologically distinct pathways has been hypothesized as a basis for localized AV nodal reentry and supraventricular arrhythmias. METHODS AND RESULTS Extracellular bipolar and intracellular microelectrodes were used to record activation in the superfused rabbit AV junction. A subset of rabbit hearts (n=19 of 72) demon...

introduction: recent studies have shown acute cardioprotective effects of cyclosporine. the aim of the present study was to determine the protective role of cyclosporine on the model simulated the rotational nodal arrhythmia (avnrt) by using extracellular field potential recordings of isolated atrioventricular-node (av-node) of rabbit. methods: this study was performed on isolated double-perfus...

Discrete radiofrequency lesion at the atrial insertion site of the tendon of Todaro in the perfused rabbit preparation lengthens A-H interval, mimicking fast pathway input ablation. This study attempts to define the cellular electrophysiology of the ablation region prior to and after the elimination of fast AV node conduction. In six superfused rabbit AV node preparations, the cellular electrop...

In the normal heart, the atrioventricular node (AVN) is part of the sole pathway between the atria and ventricles, and is responsible for the appropriate atrial-ventricular delay. Under normal physiological conditions, the AVN controls appropriate frequency-dependent delay of contractions. The AVN also plays an important role in pathology: it protects ventricles during atrial tachyarrhythmia, a...

This study 1) compares the negative chronotropic and dromotropic actions of adenosine in guinea pig, rat, and rabbit hearts; 2) investigates the mechanism(s) for the different responses; and 3) determines the physiological implications. Isolated perfused hearts were instrumented for measurement of atrial rate and atrioventricular (AV) nodal conduction time. Differences in metabolism of adenosin...

Introduction: Recent studies have shown acute cardioprotective effects of cyclosporine. The aim of the present study was to determine the protective role of cyclosporine on the model simulated the rotational nodal arrhythmia (AVNRT) by using extracellular field potential recordings of isolated atrioventricular-node (AV-node) of rabbit. Methods: This study was performed on isolated double-per...

Introduction: Previous studies have indicated a relationship between MPTP pore and AV nodal rate-dependent properties. The aim of present study was to determine acute direct effects of cyclosporine on extracellular field potential of isolated rabbit AV node during experimental atrial fibrillation. Methods: In one group of male New Zealand rabbits (1.5-2.5 kg) cumulative concentrations of cyc...

introduction: previous studies have indicated a relationship between mptp pore and av nodal rate-dependent properties. the aim of present study was to determine acute direct effects of cyclosporine on extracellular field potential of isolated rabbit av node during experimental atrial fibrillation. methods: in one group of male new zealand rabbits (1.5-2.5 kg) cumulative concentrations of cyclos...

To evaluate the role of perinodal tissue in the genesis of atrioventricular (AV) nodal reentry, echo beats were induced by programmed stimulation in nine superfused rabbit atrial-atrioventricular nodal preparations. In these preparations, extracellular bipolar electrograms were recorded simultaneously from the crista terminalis, interatrial septum arid His bundle, along with microelectrode acti...