Catheter ablation is an established curative treatment for accessory pathways (APs), but in spite of the great progress made in the diagnosis and treatment, there is limited knowledge of the underlying cellular pathophysiology that determines the different clinical presentations. The case presented highlights the complex presentation and properties of some APs that can be encountered at the tim...

This study concerns two cases of chronic 2 degrees atrioventricular (A-V) block with left bundle branch block (LBBB). Pathological studies included serial section of the conduction systems. Case 1 had type I 2 degrees block with LBBB. Electrophysiological studies revealed type I 2 degrees block proximal to the His bundle recording site and a prolonged H-V interval (60 msec). Pathologically ther...

Twelve patients with evidence of Mahaim fibers are reported, six with nodoventricular (NV) fibers and six with fasciculoventricular (FV) fibers. All patients with NV fibers had left bundle branch block morphology, and a sustained reentrant tachycardia with this morphology was proved in each case. In three of the six, ventriculoatrial dissociation occurred during tachycardia. We postulate that t...

Atrial, His bundle (H), and ventricular electrograms were recorded by an electrode catheter in unanesthetized man. Conduction time through the atrioventricular (A-V) conduction system was subdivided into A-V nodal (A-H interval) and ventricular specialized conduction system (H-V interval). The right atrium was driven at a constant rate and the pattern of A-V conduction of premature atrial test ...

We describe a case of a young man referred with a broad complex tachycardia for evaluation and ablation. Electrophysiological study was performed and revealed a left lateral accessory pathway with antegrade decremental conduction causing antidromic reciprocating re-entrant tachycardia. Ablation was successfully performed. Left lateral accessory pathways with decremental conduction are rarely en...

Background. The developmental mechanisms underlying the

BACKGROUND QRS narrowing following cardiac resynchronization therapy with biventricular (BiV) or left ventricular (LV) pacing is likely affected by patient-specific conduction characteristics (PR, qLV, LV-paced propagation interval), making a universal programming strategy likely ineffective. We tested these factors using a novel, device-based algorithm (SyncAV) that automatically adjusts paced...

INCOMPLETE TRANSMISSION of impulses across the atrioventricular (A-V) junction has held a special fascination for many investigators.'14 Varied investigational techniques including venous pulse waves, standard electrocardiograms, and direct catheter electrode recordings from the cardiac chambers have been used to further the understanding of retrograde transmission of impulses into the A-V junc...