Fluorescent optical mapping of cardiac electrophysiology in animal models has produced a wealth of information about the function of the cardiac pacemaking and conduction system. However, expanding optical mapping studies to the human conduction system will significantly increase our understanding of clinically relevant phenomena, such as atrioventricular nodal reentrant tachycardia, that are d...

To facilitate the explanation of Fig. 1, the QRS complexes are labelled. The first two show a normal QRS preceded by a normal PR interval. Thereafter the QRS configuration changes. Complexes 3 to 6 show gradual widening, a frontal axis shift to horizontal and loss of the initial q in leads I and V6, an rS pattern in lead III, and the development of a left bundle branch block-like QRS configurat...

Two patients who had an endocardial cushion type of ventricular septal defect underwent electrophysiologic studies for detection of specialized conduction tissue during operative repair. In one patient, with an inferior leftward frontal plane QRS axis on the ECG, we recorded an intraventricular His bundle electrograms from both the anterosuperior and posteroinferior margins of the defect, sugge...

T HE HIS BUNDLE is a narrow, cylindrical, structure which connects the atrioventricular (A-V) node with the bundle branches (fig. 1) and is composed of a penetrating and a branching portion. The former begins in the A-V node and ends where it emits the posteroinferior fibers of the left bundle. The branching portion extends from the latter site to the origin of the right branch (which is also c...

Complete right bundle branch block manifests with a rSR' configuration in right orientated leads and a duration of 0.12 sec or longer. Incomplete right bundle branch block is perceived as this classic rSr' configuration and a duration of less than 0.12 sec. This presentation reflects the early development of right bundle branch block which first manifests with a hitherto undescribed sign, namel...

We have confirmed a supraventricular origin of bidirectional tachycardia with simultaneous standard electrocardiograms and a His bundle electrogram. The patient had sinus rhythm, variable trifascicular block and atrioventricular block below the His bundle. Ventricular excitation varied among three patterns which included right bundle branch block with right axis deviation (RBBB-RAD), right bund...

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...

BACKGROUND Isolated right bundle branch block (RBBB) is a common finding in the general population. The atrioventricular node (AVN) artery contributes to the blood supply of the right bundle branch. Our hypothesis was that the anatomy of the AVN artery and the pattern of dominancy differ between subjects with and without RBBB. METHODS We retrospectively studied the coronary angiography of 92 ...

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...