Effect of Dual Atrioventricular Node Pathways on Atrioventricular Reentrant Tachycardia

Background Dual atrioventricular (AV) node pathway physiology is frequently observed in patients with AV accessory pathways. Methods and Results To examine the implications of this, we identified 36 patients (19 men and 17 women; mean±SD age, 30±13 years) with both phenomena. The 36 patients had 48 accessory pathways. Twenty-seven patients had bidirectional and 9 had unidirectional accessory pathways. Of the 34 patients with inducible atrioventricular reentry, 17 used the slow and 11 used the fast anterograde AV node pathway exclusively during AV reentrant tachycardia, whereas 6 patients used both the fast and the slow AV node pathways. AV node reentrant tachycardia was inducible in addition to AV reentry in 7 patients. Both the cycle length and AH intervals were significantly longer during slow pathway–dependent (cycle length, 411±58 milliseconds [ms]; AH, 229±42 ms) than during fast pathway–dependent (cycle length, 322±40 ms; AH, 121±25 ms; P<.05) reentrant tachycardias. Two patients had only AV node re...