Rapid mapping and differentiation in ventricular outflow tract arrhythmia using non-contact mapping

Purpose Ventricular outflow tract arrhythmias (VOTAs) can be successfully treated by catheter ablation. However, it is sometimes difficult to differentiate the origin of VOTAs between the right ventricular outflow tract (RVOT) and the other sites, leading to a long fluoroscopy time and unnecessary radiofrequency applications. This study aimed to clarify distinguishable characteristics of the propagation pattern obtained from non-contact mapping (NCM) for VOTA ablation. Methods Consecutive 45 patients with VOTAs who underwent catheter ablation using the NCM system were included in this study. We analyzed an isopotential map on three-dimensional geometry of the RVOT obtained from the virtual unipolar electrograms (VUEs) and assessed mapping data of the isopotential area with an initial negative VUE of −1 mV. Results Successful ablation was achieved from the endocardial RVOT in 34 patients (RVOT group) and the non-RVOT in 11 (non-RVOT group). Major and minor axis diameters of the isopotential area did not significantly differ between the two groups. However, a ratio of major/minor axis diameter was greater in the RVOT group (1.9 ± 0.1 versus 1.3 ± 0.1; P