Relationship between Effective Refractory Period and Inducibility of Atrial Fibrillation from the Superior Vena Cava after Pulmonary Vein Isolation

Background: In terms of the pulmonary vein (PV), atrial fibrillation (AF) patients have a shorter effective refractory period (ERP) and a larger dispersion of the ERP than patients without AF. Although the frequency of AF from the superior vena cava (SVC) was the highest among non-PV foci, the characteristics of the ERP in the SVC (SVC-ERP) were unclear. The purpose of this study was to elucidate the relationship between SVC-ERP and the inducibility of AF after pulmonary vein isolation (PVI). Methods and Results: Consecutive 28 patients who underwent PVI were included. After successful PVI, the SVC-ERP was measured at three positions in SVC. Rapid electrical stimuli were delivered at the shortest SVC-ERP to induce AF. Patients in whom AF was induced were assigned to the SVC-induced group (SIG) and the remaining patients were the non-SVC-induced group (non-SIG). The size of the SVC sleeve was evaluated using three-dimensional electroanatomic mapping. The SIG had a significantly shorter average SVC-ERP (236.0±25.2 vs. 294.8±36.8 ms, p