First experience and validation of the extended early meets late (EEML) tool as part of the novel CARTO software HD COLORING

Background With CARTO HD COLORING, a new enhanced software-based map visualization is available to highlight among others potential areas of conduction block in complex arrhythmias (extended early meets late (EEML)). The ideal settings of thresholds are still unclear and are examined here by studying 12 left atrial arrhythmias. Methods Ten patients with left atrial tachycardia underwent high-density activation mapping of the left atrium. Areas of local conduction block were visualized with different extended early meets late (EEML) thresholds (75/25%; 80/20%; 85/15%; 90/10%) and compared with ripple maps for verification. Results Settings of 80/20% or 85/15% were more accurate than the default settings of 75/25% in displaying the actual amount of conduction block as assessed by ripple maps. Conclusion HD COLORING leads to further insights into complex tachycardias through a new Voxel Map Surface Concept and color-based visualization of local conduction block. It can be assumed that individual adaption of extended early meets late (EEML) thresholds should be applied for a more accurate visualization of local conduction block.