We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch...

HOLMES, J. E. AND Mr. R. ADEY. Electrical activity of the entorhinal cortex during conditioned behavior. Am. J. Physiol. I 99 (5) : 741-744. 1960.-A 4-6-cps wave form was observed in the entorhinal cortex of 8 out of IO cats studied with the implanted electrode technique. When the animals were trained to approach a concealed food reward, the slow waves always accompanied the act of walking to t...

There is no consensus oti the effect of slow pathway ablation on the electrophysiologic properties of the fast pathway in patients with AV ncxial reentrant tachycardia. Some investigators have demonstrated that ahlation of the slow pathway results In shortening of the fast pathway effective refractory period, while other investigators have not made this observation.' '̂ In the setting of sympath...

Atrial electrograms recorded from target sites during radiofrequency catheter ablation of the slow atrioventricular (AV) nodal pathway are often fractionated and may be associated with a late, high frequency component (the slow pathway potential). The purpose of the current study was to assess the effects of slow pathway ablation on the morphology of the atrial electrogram and to determine whet...

Background. The circuit of atrioventricular (AV) nodal reentrant tachycardia may include perinodal atrial myocardium. Furthermore, in patients with dual AV nodal pathways, the atrial insertion of the slow pathway is likely to be located near the ostium of the coronary sinus, caudal to the expected location of the AV node. The present study was designed to evaluate the safety and efficacy of sel...

AIMS The objective of this prospective study was to assess risk factors for the development of atrioventricular block following slow pathway modification in patients with atrioventricular nodal reentrant tachycardia and a pre-existing prolonged PR interval. METHODS AND RESULTS Of 346 consecutive patients with atrioventricular nodal reentrant tachycardia undergoing slow pathway modification, 1...

The exact electroanatomic circuit responsible for atrioventricular nodal reentrant tachycardia (AVNRT) remains poorly understood. Initially, the pathological substrate was thought to be a small reentry circuit within the compact AV node (AVN).1 However, through a series of detailed histological studies,2 computer modeling,3 optical mapping,4 and uniquely insightful observations of tachycardia b...

Catheter ablation is an accepted, highly effective modality of treatment for cardiac arrhythmias in children. The success rate depends on the operator's experience, especially in cases involving complex anatomies. We hereby report our recent experience of successful ablation of accessory pathways in three children with complex congenital heart diseases. The first case was a 7-year-old girl with...