Dual AV node pathway physiology in patients with Wolff-Parkinson-White syndrome.

Published data on the relationship between dual AV node pathway physiology, locations and numbers of accessory pathways are limited. The purpose of this study is to appraise the dual AV node pathway physiology in a large group of patients with accessory AV pathways. A consecutive series of 759 patients was included for analysis. The incidence of antegrade or retrograde dual AV node pathway physiology and AV node reentrant tachycardia was similar for patients with accessory pathway at different locations. However, the incidence of bidirectional dual AV node pathway physiology (11.1%) and fast-slow type AV node reentrant echo (8.3%) was significantly higher in anteromidseptal accessory pathways. The incidence of antegrade (24.2% vs. 30.8%, P > 0.05), retrograde (4.9% vs. 2.9%, P > 0.05) and bidirectional dual AV node pathway physiology (3.0% vs. 2.9%, P > 0.05) was similar between the patients with a single pathway and multiple accessory pathways. Furthermore, the patients with multiple accessory pathways had a higher incidence of slow-fast form AV node reentrant tachycardia (8.8% vs. 3.0%, P = 0.034) and fast-slow form AV node reentrant echo (8.8% vs. 2.7%, P = 0.02). Thirty-four patients (4.5%) received slow pathway ablation for AV node reentrant tachycardia and none had recurrent tachycardia during the follow up period (26 +/- 7, range 1-56 months). We conclude that it is possible to find dual AV node pathway physiology in patients with accessory pathways because this phenomenon was not rare, especially in patients with a single pathway located in the anteromidseptal area or in patients with multiple accessory pathways.