Mahaim conduction producing left axis deviation and normal QRS.

Left axis deviation: a reassessment.

This report deals with the ramifications of the concept of left axis deviation. In early life, the leftward shift of the frontal plane QRS axis is determined chiefly, if not solely, by the relative weights of the ventricles. Once adult ventricular weight ratios are reached, there is a long period of axis stability, then a gradual leftward drift of the QRS, governed principally by left anterior ...

Mahaim Fiber Accelerated Automaticity and Clues to a Mahaim Fiber Being Morphologically an Ectopic or a Split AV Node

Mahaim Fiber tachycardia characteristically causes a wide QRS tachycardia with left bundle branch morphology and left axis deviation, especially in young patients, having no structural heart disease. Mahaim fiber automaticity further cements the proposition of Mahaim fiber, due to its Atrioventricular (AV) node like property, being called as an ectopic AV node.

Study of intraventricular conduction times in patients with left bundle-branch block and left axis deviation and in patients with left bundle-branch block and normal QRS axis using His bundle electrograms.

Atrial ventricular conduction system in left bundle-branch block with normal QRS axis.

In nine patients with left bundle-branch block (LBBB), normal QRS axis, and normal P-R interval, atrial, His bundle, and ventricular electrograms were recorded. The extrastimulus method was utilized to determine the relative refractoriness of the various components of the atrioventricular conducting system. The functional refractory period (FRP) of the A-V node was normal in all but one patient...

A surprising finding after adenosine administration

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...