Mapping systems
A three-dimensional (3D) mapping system as the CARTO system (Biosense Webster) or the EnSite system (Abott) was used. A 7-Fr 20-electrode catheter (BeeAT, Japan Lifeline Co. Ltd, Tokyo, Japan) was placed around the tricuspid valve annulus with the distal poles in the coronary sinus. Following access to the LA, 3D geometry was created with a circular mapping catheter (LASSO; Biosense Webster or Inquiry Optima; Abott) or high-resolution catheter (PENTARAY; Biosense Webster or Advisor HD Grid; Abott). Both color isochronal and propagation maps were generated. In the bipolar potential peak-to-peak, the scar area was set as less than 0.1 mV, and the low voltage area was set as 0.1 to 0.5 mV.13 The gap in this study was defined as the reconnection site where the Maze procedure was performed whether there were slow conduction or not. Space surrounding the pulmonary veins was counted as a gap.
We suspected approximate macroreentrant AT circuits using color-coded 3D electroanatomic activation mapping.12, 14Macroreentrant AT was diagnosed when at least 2 atrial pacing sites were within the circuit. Sites were considered within the circuit as previously described.9 Non-macroreentrant-AT was defined as occurring from a very small area (< 1 cm) and propagating to the atrium in a centrifugal pattern.15, 16