Abstract

Background - Nodoventricular (NV) and nodofascicular (NF) accessory pathways (AP) are uncommon connections between the AV node and the fascicles or ventricles. Methods - Five patients with NF or NV tachycardia were studied. Results - We identified 5 patients with concealed, left-sided NV (n=4) and NF (n=1) AP. We proved the participation of AP in tachycardia by delivering His-synchronous PVCs that either delayed the subsequent atrial electrogram or terminated the tachycardia (n=3), and by observing an increase in VA interval coincident with left bundle branch block (LBBB) (n=2). The APs were not atrioventricular pathways because the septal VA interval during tachycardia was <70ms in 3, 1 had spontaneous AV dissociation, and in 1 the atria were dissociated from the circuit with atrial overdrive pacing. Entrainment from the right ventricle showed ventricular fusion in 4 out of 5 cases. A left-sided origin of the AP was suspected after failed ablation of the right inferior extension of AV node in 3 cases and by observing a VA increase with LBBB in 2 cases. The NF and 3 of the NV AP were successfully ablated from within the proximal coronary sinus (CS) guided by recorded potentials at the roof of the CS, and 1 NV AP was ablated via a transseptal approach near the CS os. Conclusions - Left-sided NF and NV AP appear to connect the ventricles with the CS musculature in the region of the CS os. Mapping and successful ablation sites can be guided by recording potentials within or near the CS os.

View details for DOI 10.1161/CIRCEP.119.007853

View details for PubMedID 32286853