Localization and radiofrequency ablation of atriofascicular pathways using electroanatomic mapping

Atriofascicular pathways supporting antidromic reentrant tachycardia are uncommon, and may be difficult to ablate. Traditional mapping can be associated with traumatic loss of atriofascicular conduction. Atriofascicular fibers can insert into the right bundle and will, therefore, first activate the right ventricle. In contrast to initial activation of the ventricle near the tricuspid annulus that can be seen in patients with right-sided decremental atrioventricular pathways. We used electroanatomic mapping to map and ablate the ventricular insertion of atriofascicular pathways in two patients during sinus rhythm and during atrial pacing. In our 2 cases an atriofascicular potential was recorded from below the tricuspid valve annulus and tagged. At this site, each pathway was ablated with one radiofrequency lesion. We describe 2 cases where electroanatomic mapping of the right ventricle was used to map and ablate atriofascicular pathways.