Atrioventricular junctional tachycardia with rate (acceleration)-dependent aberrancy" (2006).

Mahaim fibres are cardiac accessory bundles which can cause dangerous tachyarrhythmias. Despite their first description being many years ago, their recognition and diagnosis still proves difficult. The electrocardiographic features of Mahaim pathways are subtle and shared with other accessory pathways; as such, an electrophysiology study must be used to diagnose this pathway. Even then, it is o...

BACKGROUND Accessory pathways may be located in close proximity to the His bundle, resulting in a high risk of heart block during attempted surgical or electrical interruption of these pathways. This study reports the prevalence, ECG characteristics, and results of catheter ablation of parahissian accessory pathways. They were defined on the basis of both the presence of a high amplitude (> 0.1...

INTRODUCTION AND OBJECTIVES The development of ablation techniques for supraventricular arrhythmias in patients with Ebstein's anomaly have led to a need for better understanding of the morphology of the triangle of Koch and the position of the atrioventricular (AV) node in this structure. METHODS The study involved 17 human hearts: 11 with Ebstein's anomaly (age range: 37 weeks' gestation to...

In the normal heart, an insulating barrier separates the atria and ventricles. The only way in which electrical impulses can cross this barrier is via the atrioventricular (AV) node, which delays impulse conduction to ensure the forward flow of the blood. However, in some individuals, additional muscular bundles (accessory pathways) allow rapid conduction of electrical impulses from the atria t...

Background—Atriofascicular and decremental atrioventricular pathways are variants of accessory pathways with anterograde decremental conduction properties. They result in typical wide Quantronic Resonance System (QRS) tachycardia of left bundle branch block morphology. Data on the sinus rhythm electrocardiographic characteristics are limited. Methods and Results—Thirty patients with accessory p...

The phenomenon of the "gap in atrioventricular conduction" was studied in eight human subjects, using a catheter technique for recording electrical activity of the His bundle. Premature atrial stimuli were applied throughout the basic atrial cycle, either during sinus rhythm or atrial pacing. As the coupling interval between the basic (A j) and premature (A2) atrial depolarizations was decrease...

The course of the atrioventricular conducting tissues was studied in IO hearts having ventricular septal defects. Seven of the defects were in the membranous portion of the septum, and in these hearts the common atrioventricular bundle passed down the posterior edge of the defect and bifurcated on its inferior border. In 3 of these specimens the bundle deviated to the left side of the septum be...

The Taussig-Bind group of hearts is that group in which the aorta emerges completely from the right ventricle, unrelated to the position of the ventricular septal defect (VSD), while the pulmonary trunk emerges at varying degrees from the right ventricle related to the location of the VSD. Several types of surgical procedures involve the VSD in these hearts. The conduction systems in six of the...

Atrioventricular (AV) conduction was studied in anesthetized, open-chest, 1-35-day-old goats. Atrial, bundle of His, and ventricular bipolar electrograms were recorded, and the functional refractory periods of the AV conduction system and the ventricles were determined. Supraventricular premature excitation invaded the ventricles during their vulnerable period. This AV conduction property is di...