To determine the role of pectinate muscle (PM) bundles in the formation of intra-atrial reentry, 10 isolated canine right atrial tissues were perfused with Tyrode's solution containing 1 to 2.5 micromol/L acetylcholine (ACh). The endocardium was mapped using 477 bipolar electrodes with 1.6-mm resolution. Reentry was induced by a premature stimulus (S2). Computer simulation studies were used to ...

REENTRY HAS BEEN FREQUENTLY proposed as a mechanism for a variety of cardiac arrhythmias. For certain types of arrhythmias, the role of reentry appears well established.1 10 While intra-atrial reentry has long been suspected as a mechanism of some form of atrial arrhythmias, the phenomena of interor intra-atrial reentry in man have rarely been documented.8 11 The inability to demonstrate intero...

avnrt, (atrioventricular nodal reentry tachycardia), atrial tachycardia and atrial flutter are 3 kinds of supraventricular tachycardia, which their mechanism are explained based on reentry. a 60-years-old man is presented with all of the above-mentioned arrhythmias, responsive to intravenous injection of adenosine. radiofrequency ablation of the slow pathway territories cured all of them. there...

THE QUESTION WHETHER tachyarrhythmias are caused by enhanced impulse formation (“focus”) or by reentrant excitation (“reentry”) has been the subject of debate for more than a century. In 1887 McWilliam (12) was the first to suggest that disturbances in impulse propagation could be responsible for fibrillation, and he clearly envisaged the possibility that myocardial fibers could be reexcited as...

In five patients, bundle of His electrograms were recorded during right ventricular pacing at various cycle lengths. In all patients, as the cycle length of stimulation was decreased, the pattern of retrograde conduction proceeded from 1:1 retrograde conduction to retrograde Wenckebach with or without manifest reentry, to retrograde Wenckebach cycles with concealed reentry. The requisite condit...

In five patients, bundle of His electrograms were recorded during right ventricular pacing at various cycle lengths. In all patients, as the cycle length of stimulation was decreased, the pattern of retrograde conduction proceeded from 1:1 retrograde conduction to retrograde Wenckebach with or without manifest reentry, to retrograde Wenckebach cycles with concealed reentry. The requisite condit...

background : lifting methods, including standing stance and techniques have wide effects on spine loading and stability. previous studies explored lifting techniques in many biomechanical terms and documented changes in muscular and postural response of body as a function of techniques .however, the impact of standing stance and lifting technique on human musculoskeletal had not been investigat...

RATIONALE Reentry underlies most ventricular tachycardias (VTs) seen postmyocardial infarction (MI). Mapping studies reveal that the majority of VTs late post-MI arise from the infarct border zone (IBZ). OBJECTIVE To investigate reentry dynamics and the role of individual ion channels on reentry in in vitro models of the "healed" IBZ. METHODS AND RESULTS We designed in vitro models of the h...