Patterns of ventriculoatrial conduction have been used to distinguish retrograde conduction over an accessory atrioventricular pathway from that over the normal atrioventricular conduction system. Ventriculoatrial conduction at a constant interval during incremental ventricular pacing and during progressive prematurity of ventricular extrastimuli has been considered characteristic of conduction...

A case of atrioventricular reciprocal rhythm and chronic reciprocating tachycardia in a newborn infant is presented. Electrophysiological studies suggest that these rhythm disturbances are related to the presence of a right-sided atrioventricular accessory pathway capable only of retrograde conduction (concealed Wolff-Parkinson-White syndrome). The technique of recording the sequence of atrial ...

His bundle electrograms were performed in 4 patients illustrating the varied aspects of the preexcitation syndrome. In 3 cases of Wolff-Parkinson-White syndrome the QRS complexes were found to be formed by fusion between the normal and premature activation processes. In one of these cases a re-entry tachycardia was shown, with antegrade conduction occurring through the His bundle and retrograde...

His bundle ablation was performed in a 48 year old man with drug refractory orthodromic atrioventricular reentrant tachycardia and paroxysmal atrial fibrillation. Reentry was caused by a left free wall concealed accessory pathway. Interruption of the His bundle by low energy direct current shock (25 J) was quickly followed by anterograde conduction via the accessory pathway, with various forms ...

Since they were first described, preexcitation syndromes have intrigued physicians. The interest derives in part from the myriad bizarre electrocardiographic abnormalities associated with these syndromes and from the variety of complex arrhythmias that may be manifested in affected patients. Symptomatic tachycardias develop in patients with the Wolff–Parkinson–White syndrome because there is co...

I Wellens HJJ, Brugada P, Penn OC, Gorgels AP, Smeets J. Pre-excitation svndromes: clinical presentation, course and therapy. In: Zipes DP, Jalife J, eds. Cardiac electrophvsiology: from cell to bedside. Philadelphia: W B Saunders, 1990:691-702. 2 Klein GJ, Bashore TM, Sellers TD, Pritchett ELC, Smith WM, Gallagher JJ. Ventricular fibrillation in the Wolff-Parkinson-White syndrome. N Engl3' Med...

A 67-year-old man with Wolff-Parkinson-White syndrome type A presented with second degree atrioventricular block in anomalous pathway and complete infra-Hisian block in the His-Purkinje pathway. He had increasingly frequent attacks of dizziness not related to exercise. A permanent ventricular demand pacemaker was successfully implanted following intracardiac electrophysiological studies.

Ventricular preexcitation, a feature of Wolff-Parkinson-White syndrome, is caused by accessory myocardial pathways that bypass the annulus fibrosus. This condition increases the risk of atrioventricular tachycardia and, in the presence of atrial fibrillation, sudden death. The developmental mechanisms underlying accessory pathway formation are poorly understood but are thought to primarily invo...

Radiofrequency ablation is the interventional therapy of choice for the definitive cure of patients with tachycardias facilitated by accessory pathways. Ablation of an accessory pathway at sites close to the His bundle is inevitably associated with an increased risk of causing complete atrioventricular block. Here we describe the case of a patient with pre-excitation syndrome and episodes of su...

We report a case of a 7-year-old girl with atriofascicular Mahaim (AFM) pathway concomitant with Ebstein's anomaly. The QRS wave showed left bundle branch block pattern on electrocardiogram. Holter electrocardiogram showed prolongation of the PR interval and QRS morphological change during sinus tachycardia. An electrophysiological study demonstrated that the distal His potential appeared earli...