We have analysed the ventricular response as seen on the surface electrocardiogram in patients with paroxysmal atrial fibrillation and flutter in relation to the electrophysiological properties of the corresponding atrioventricular pathways. In 15 patients who had atrial fibrillation with conduction solely through the atrioventricular node, there was a significant correlation between th shortes...

Pacemaker and conduction system myocytes play crucial roles in initiating and regulating the contraction of the cardiac chambers. Genetic defects, acquired diseases, and aging cause dysfunction of the pacemaker and conduction tissues, emphasizing the clinical necessity to understand the molecular and cellular mechanisms of their development and homeostasis. Although all cardiac myocytes of the ...

We have studied the disposition of the cardiac conducting tissues in four hearts from situs solitus individuals possessing primitive ventricles without outlet chambers. These hearts correspond to the type of univentricular heart defined as common ventricle by Lev. All the hearts studied possessed normally positioned great arteries. Two groups, each consisting of two hearts, could be distinguish...

The rhythmic contraction of our heart is controlled by electrical impulses that travels throughout the cardiac muscle. signal generated sinus node, which can be thought as natural pacemaker heart. This impulse spreads from its initiation in SA node atria through specialized internodal pathways, to atrial myocardial contractile cells and atrioventricular node.This term paper reviews anatomy Acti...

Article type: Case Report Cardiac rhabdomyomas are the most common primary cardiac tumors in children. These tumors are generally asymptomatic, although they may be associated with neonatal tuberous sclerosis complex. Despite the fact that thyroid dysfunction rarely occurs in tuberous sclerosis, papillary adenomas (hamartomas) of the thyroid gland have been reported in a number of autopsies. He...

Transvenous ablation of atrioventricular conduction by high energy shock through a pacing wire has been used as a method of controlling the ventricular response to rapid atrial arrhythmias. A patient in whom this technique successfully controlled refractory tachycardia was admitted with severe left ventricular impairment five months after the procedure and died. The heart was examined at necrop...

The well-known paradoxic behavior of atrioventricular conduction, the so-called gap phenomenon, that occurs when impulses within a certain range of coupling intervals are blocked while impulses with shorter coupling intervals are conducted is attributed to differences in properties of refractoriness in neighboring regions of the conduction system. In contrast, in the present study a model was d...

Atenolol, a cardioselective beta-blocking agent, at dose levels of 0.03, 0.06, and 0.12 mg/kg intravenously, produced prolongation of atrioventricular nodal conduction in 22 patients with suspected coronary artery disease. In a dose of 0.12 mg/kg body weight atenolol produced significant prolongation of sinus cycle length, sinus node recovery time, atrioventricular node conduction, and the effe...

The atrioventricular (AV) node is the only conduction pathway between the atria and ventricles, it is located at the base of the right atrium. The conduction through the atrioventricular node is slow to allow the atria to pump blood into the ventricles before they contract. It also acts as a backup pacemaker, in case the sinoatrial node fails and limits the number of action potentials conducted...