3.3. Left atrial mapping
Following PVI, detailed voltage mapping using a 20-pole circular catheter with 1-mm electrodes (LassoNaV, Biosense Webstar) was performed during 100-beat-per-minutes paced rhythm from the high right atrium. Mapping points were automatically acquired using the CARTO Confidence module with the following settings: cycle length filtering, ±30 msec; local activation time stability, < 3 msec; position stability, < 2 mm; and density, < 1 mm. Left atrial geometry was conducted in fast-anatomical mapping mode. Mapping was continued to fill all color gaps on the voltage map with an interpolation threshold of 17 mm for the fill threshold and 10 mm for the color threshold. If poor contact between the circular mapping catheter and endocardium surface was suspected, mapping using the ablation catheter was added with a point acquisition setting of contact force ≥ 5 g. The band pass filter was set at 30 to 500 Hz.