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...

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...

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...

Sinus node recovery time was compared to the recovery time of a slow atrioventricular junctional rhythm in each of the same seven pentobarbital anesthetized dogs. Recovery time and the first five cardiac cycles were examined after pacing atria and ventricles for 20, 40, and 60 seconds at four or more pacing cycle lengths. Data relating recovery times and return to control conditions to prepacin...

Potentials recorded at various sites in the atrioventricular (A-V) conduction system indicate that conduction is continuously electrical in nature and involves no synapse-like (i.e., chemical) conduction. The region between atrium and atrioventricular node has the slowest conduction velocity (.05 M./see.) and lowest safety factor. Conduction through the A-V node is at about .12 M./sec. Results ...