The chronotropic responses of isolated sinoatrial node and ventricular muscle cells to neurotransmitters were compared in vitro with and without selective adrenergic and cholinergic innervation. Explants of either thoracolumbar sympathetic ganglion or sacrococcygeal spinal cord were added to cultures of newborn rat sinus node regions or ventricular apexes harvested before the onset of autonomic...

assumes control over the ventricles. When this happens, two types of auriculo-ventricular rhythm may arise. One is called A-V nodal rhythm and is recognized by the inverted P waves, which are as a rule either abnormally close to the QRS complex or may follow it. The second type of auriculo-ventricular rhythm is known as A-V dissociation, characterized by the rate of the ventricular contractions...

AIMS To assess the results of transcatheter ablation of cardiac arrhythmias in Latin America and establish the first Latin American transcatheter ablation registry. METHODS AND RESULTS All ablation procedures performed between 1 January and 31 December 2012 were analysed retrospectively. Data were obtained on the characteristics and resources of participating centres (public or private instit...

Aside from the nerve fibers which enter the pace-making node from the subepicardium, there were observed within the limits of the node a few ganglionic cells and a plexus of moniliform nerve fibrils in very close relation to its muscle fibers, hence the sino-auricular node, like the auriculo-ventricular, may be considered from a histological standpoint a neuromuscular organ.

Double ventricular response is a rare arrhythmia that results from simultaneous antegrade conduction over the fast and slow pathways of AV node. Double ventricular responses may lead to arrhythmia-related cardiomyopathy. As far as we know, there is not any reported reversible cardiomyopathy development that resulted from double ventricular responses to one atrial impulse after slow pathway abla...

In anesthetized dogs the vagus nerve was stimulated for 2 min; during the first minute the ventricles were driven at a rate higher than the control sinus rate; after discontinuation of the drive, the duration of asystole was prolonged. When the ventricles were driven at a rate lower than the sinus rate during vagal stimulation the subsequent asystole was shortened. Slowing sinus activity by gra...

BACKGROUND Catecholaminergic polymorphic ventricular tachycardia is a disease characterized by ventricular arrhythmias elicited exclusively under adrenergic stress. Additional features include baseline bradycardia and, in some patients, right ventricular fatty displacement. The clinical spectrum is expanded by the 2 families described here. METHODS AND RESULTS Sixteen members from 2 separate ...

BACKGROUND The anatomic-electrophysiological correlation of AV nodal reentry is unclear. To localize reentrant circuits during atrial and ventricular echoes and to characterize sites of slow conduction and block, we correlated histology with electrophysiology of the AV node. METHODS AND RESULTS In 10 isolated dog hearts, extracellular electrical activity was recorded in Koch's triangle at 208...

Postmortem findings within the cardiac conduction system are described from the case of a black woman with sarcoid heart disease who died suddenly. Her clinical course had been characterized by recurring ventricular arrhythmias and bouts of syncope. Both the sinus node artery and the atrioventricular (A-V) node artery were sites of focal fibromuscular dysplasia, which thickened slightly the wal...

Clinical trials in patients with pacemakers for sinus node dysfunction or atrioventricular block have highlighted the fact that desynchronization of ventricular contraction induced by right ventricular apical pacing is associated with long-term morbidity and mortality. These clinical data confirm pathophysiological results indicating that right ventricular apical pacing causes abnormal ventricu...