2.5 Real-Time Phase Mapping
After the integration of the anatomical 3D models of the LA and PVs obtained from the MRI, mapping was performed using the NavX system (Abbott, Chicago, IL) as a guide. A 20-pole circular mapping catheter (OptimaTM or Reflexion HDTM, Abbott) and ablation catheter-reconstructed LA posterior anatomy was aligned with the MRI.13 To detect the distribution of the AF drivers, an online real-time phase mapping system (ExTRa Mapping) was used. The detail of this mapping system was previously described.7 ExTRa Mapping was applied to persistent AF patients and as a result, each wave dynamics were classified into 3 patterns, meandering rotors (MRs), multiple wavelets (MWs), and planar wave. Planar wave propagation was defined as passive activation, whereas MR and MW were defined as non-passive activations. Furthermore, non-passively activated areas (NPAs), a region where non-passive activations were frequently observed, were automatically detected according to the value of the “non-passively activated ratio (%NP)” (the ratio of the form of MRs and/or MWs assumed to contain AF drivers to the recording time).5NPAs were determined as areas up to the top 7 highest %NP values greater than 50%. Thus, the NPAs could be considered as the area where AF drivers could be frequently found. To evaluate the distribution of the NPAs, the region of the whole LA was divided into the following 8 segments: PV antrum, roof, anterior, posterior, lateral, bottom, septum, and left atrial appendage (LAA) base segments. Moreover, we evaluated the proportion of MRs and MWs in the %NP within the NPAs in the lesser and heterogenous LGE areas.