Introduction: Endorphins are produced by cardiomyocytes, and exert different effects on the heart. The aim of the present study is to assess morphine effects on extracellular atrioventricular (AV) node field potential pattern and ventricular rhythm of isolated rabbit heart during experimental atrial fibrillation (AF). Methods: Effects of different concentrations of morphine (10, 20, 50 and 1...

background: ventriculoatrial (va) conduction has an important role in the initiation and maintenance of some arrhythmias. the aim of this study was to evaluate whether clinical and electrophysiological parameters of atrioventricular (av) conduction can predict va conduction. methods: detailed demographic, electrocardiographic, and echocardiographic data were recorded in 54 consecutive patients ...

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: Intranodal pathways of atrioventricular (AV) node play a vital role in the delay of conduction time in response to various atrial inputs. The present study was aimed to determine the frequency-dependent electrophysiological properties of concealed slow pathway according to a functional model of isolated rabbit atrioventricular node preparation after fast pathway ablation. Meth...

Introduction: Recent evidence has indicated that statins can reduce the incidence of both supraventricular and ventricular arrhythmias with various mechanisms. The primary goal of the present study was to determine direct protective role of simvastatin in modifying concealed conduction and the zone of concealment in a simulated model of atrial fibrillation (AF) in an isolated atrioventricula...

Paroxysmal supraventricular tachycardia most commonly arises from reentry within the atrioventricular (AV) node. Although ablation of the His bundle has gained popularity for treating patients with AV node reentrant tachycardia refractory to medical therapy, undesirable sequelae include complete heart block and the necessity for a permanent pacemaker. To obviate this limitation, we have develop...

To evaluate the significance of the refractory period and conduction time of the AV node for reentrant tachycardias incorporating the AV node, the effective refractory period of the AV node (ERP) and AH interval (AH) during atrial pacing at various cycle lengths were measured in 12 anesthetized dogs after verapamil administration. ERP-AH tended to be constant in each dog at different cycle leng...

The perfusion of the AV node artery in dog heart in vivo was performed. After destroying the sinoatrial node by selective injection of ethanol into the sinus node artery, the selective administration of catecholamines into the AV node artery induced acceleration of nodal rhythm. In the course of recovery, eminent oscillatory change in the AV nodal rhythm was regularly observed. This oscillatory...

  Introduction : The aim of this study is to obtain new insight into possible relation between functional properties of slow concealed pathway and rate-dependent properties of AV-node.   Methods : Rate-dependent nodal properties of recovery, facilitation, and fatigue were characterized by stimulation protocols in one groups of (N=7) isolated superfused AV-Nodal rabbits. Small miniature lesions ...