Catheter ablation of atypical flutter using new 3-dimensional electroanatomic mapping software focusing on areas of conduction block

Atypical atrial flutter is a regular arrhythmia characterized by a non–cavotricuspid isthmus–dependent reentry.1, 2, 3 Atypical atrial flutter can arise from complex reentry circuits involving areas of slow electrical conduction and scar tissue in both atria. Three-dimensional (3D) activation mapping is a key tool for analysis of the wavefront propagation. However, activation mapping techniques can be very time-consuming and in some cases the mapping can be difficult to analyze, leading to ineffective ablation procedures. A new feature of the 3D electroanatomic mapping (3D EAM) system CARTO 3 version 6.0, high definition (HD) coloring (Biosense Webster, Diamond Bar, CA), allows high-quality display of the EAM, and in addition to the conventional early-meets-late (EML) it also highlights areas of potential conduction block, called extended early-meets-late (EEML), thereby providing a basis for a better interpretation of the local activation time (LAT) and propagation map. Here we report the first case completed with the HD coloring feature of an atypical atrial flutter in the right atrium and compare it with the conventional CARTO 3 software version.