During the electrophysiologic study of 435 patients referred for evaluation of WolffParkinson-White syndrome, 42 (10%) had preexcited reciprocating tachycardia (defined as a macroreentrant tachycardia that used an accessory atrioventricular [AV] pathway for antegrade conduction). The ages of the patients ranged from 9 to 67 years (27 + 14). Thirty-three were male patients, nine female, and eigh...

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...

OBJECTIVES The purpose of this study was to determine whether the response to ventricular pacing during tachycardia is useful for differentiating atypical atrioventricular node re-entrant tachycardia (AVNRT) from orthodromic reciprocating tachycardia (ORT) using a septal accessory pathway. BACKGROUND Although it is usually possible to differentiate atypical AVNRT from ORT using a septal acces...

It was recently shown that supernormal conduction in the diseased His-Purkinje system is more common than previously thought, and is always associated with prolongation of refractoriness. To assess whether supernormal conduction could also occur in the accessory pathway of patients with ventricular pre-excitation, 21 patients with manifestly prolonged refractoriness in the accessory pathway wer...

Forty-nine patients with Wolff-Parkinson-White syndrome, ages 7 weeks to 51 years, were studied with isopotential body surface maps during normal sinus rhythm, atrial pacing or induced atrial fibrillation. The location of the accessory pathway was determined by multicather electrophysiologic study or surgical ablation of the accessory pathway. When fusion was minimized and ventricular activatio...

Premature atrial stimulation was performed during His bundle recording in four patients with the type of ventricular pre-excitation in which theforward H deflection appeared after the onset of the delta wave. The AV conduction patterns occurring in these patients seemed to have depended on the physiological differences existing between normal pathway and accessory pathway (AP) at different mome...

BACKGROUND Although the anatomic "substrate" for the occurrence of antidromic reciprocating tachycardia (ART) has been previously examined, the underlying physiological substrate for this unusual arrhythmia in patients with the Wolff-Parkinson-White syndrome has not been thoroughly characterized. METHODS AND RESULTS The electrophysiological properties of the accessory pathway and normal ventr...

In three patients anterograde conduction across a previously undocumented accessory pathway was exposed by the development of atrial fibrillation. This unusual presentation illustrates the possible unmasking of the Wolff-Parkinson-White syndrome by other factors in patients who have not previously demonstrated the potential for anterograde accessory pathway conduction.

BACKGROUND Accessory pathways may be located in close proximity to the His bundle, resulting in a high risk of heart block during attempted surgical or electrical interruption of these pathways. This study reports the prevalence, ECG characteristics, and results of catheter ablation of parahissian accessory pathways. They were defined on the basis of both the presence of a high amplitude (> 0.1...