Frequencies Analysis
After the PVI, DF mapping during AF in each area was performed using the fast Fourier transform (FFT) method described previously.10,13,18,19 Recordings at each site for 5 seconds were performed using a deflectable 20-pole spiral-shaped catheter with a diameter of 2.5 cm (Reflexion HDTM, St. Jude Medical). Signals were truncated to 5 seconds at a sampling rate of 1,000Hz, providing 4,096 points for analysis (resolution 0.50Hz). The signals were rectified and processed by a Hanning window function and filtered from 2 to 20Hz. The DF analysis was done by an offline FFT analysis using the software implemented in the polygraph (RMC-5000; Nihon Kohden Co., Tokyo, Japan) in real-time and then the DF values were input manually into the NavX system. The DF value was determined as the frequency associated with the maximum peak power of the spectrum. Only DF points with a regularity index ≥0.2 were included.10,13,18,19 The high-DF sites were defined as DFs of ≥7Hz. The highest value of the DF in each mapping area in the LA was measured and calculated.