A 'concealed' accessory pathway was suspected in 12 patients because of eccentric left atrial activation during tachycardia. Retrograde conduction during ventricular pacing may occur over the atrioventricular node, the accessory pathway, or both. There were 4 patterns of ventriculoatrial conduction in response to ventricular extrastimuli (V2) at various coupling intervals: (1) exclusive accesso...

A 27-year-old man with primary oxalosis and extensive visceral involvement was maintained on long-term chronic hemodialysis. He had an episode of presyncope associated with electrocardiographic findings of an erratic atrial rhythm, atrioventricular dissociation due to an accelerated junctional rhythm and right bundle branch block. Electrophysiologic studies showed irregular atrial depolarizatio...

After right heart catheterisation in 20 subjects, aged 30 to 82 years, the techniques of intracardiac electrocardiography and programmed stimulation were used to determine variables of normal function of the sinuatrial node, atrioventricular node, and intraventricular conduction system. Specific attention was paid to autonomic influences on these variables. These were assessed by comparison of ...

The effect of alcohol (.1 mg/kg) on the sinus node and atrioventricular node was studied in 9 mongrel dogs. The sinus node function was evaluated by the sinus node recovery time and the atrioventricular node by the highest atrial pacing rate at which Wenckebach periodicity was developed. The effect was studied for 45 minutes. Three groups were identified: Group I, Low Concentration of Alcohol (...

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...

The actions of 2-methylhistamine (H1 agonists), 4-methylhistamine (H2 agonist), and histamine were studied by selective perfusion of the sinus node artery and atrioventricular node artery in 75 dogs anesthetized with pentobarbital sodium. 2-Methylhistamine and histamine had variable and inconsistent effects on the sinus rate. 4-Methylhistamine (100 microgram/ml) produced acceleration of the sin...

The electrocardiograms of 100 patients with rapid and regular PP intervals during atrial arrhythmias (because of atrial tachycardia or flutter, or pacing) were examined for periods of irregular atrioventricular conduction. This irregular conduction corresponds to an alternating Wenckebach phenomenon, of a type that can be determined from simple rules. The different types of conduction encounter...

An 18-year-old man whose sister has classic Kartagener's syndrome was found to have sinusitis, bronchiectasis, and corrected transposition with normal visceral situs. Congenital complete heart block was secondary to absence of conducting-system pathways between a small posterior atrioventricular node and the transposed His bundle and bundle branches. No anterior atrioventricular node was presen...

Modification of atrioventricular node is a usual and necessary operation to cure atrioventricular nodal reentrant tachycardia (AVNRT). In this operation, atrioventricular block is the most severe complication and its prevention is of our great concern. This complication always occurs under some special circumstances with potential risk. So, it is very important to realize such conditions, as in...

The cardiac specialized conduction tissue was studied by serial sectioning in 13 cases of situs ambiguus. In four cases of right isomerism, we found paired sinus nodes in relation to a crista terminalis, and in each case a sling of conduction tissue between two atrioventricular nodes was present regardless of the ventricular morphology or cardiac position. In the cases with left isomerism, the ...