Clinical assessment and comparison of annotation algorithms in high‐density mapping of regular atrial tachycardias

Background High‐density automated mapping of regular atrial tachycardias (ATs) requires accurate assessment of local activation times (LATs). Objective To evaluate high‐density mapping of ATs and compare the accuracy of different automated LAT annotation algorithms. Methods Fifteen patients underwent AT ablation guided by the automated ConfiDENSEۛ high‐density mapping module (Carto 3 v4) allowing manual reannotation (edited maps). For each AT, unedited automated maps were reconstructed offline by three algorithms: maximum unipolar slope (LAT Slope ), bipolar peak (LAT Peak ), and a new hybrid annotation algorithm (LAT Hybrid ). Five blinded experts were asked to define the (1) tachycardia mechanism, (2) ablation target, and (3) level of difficulty of these unedited maps. Results Twenty‐one ATs (cycle length 300 ± 46 ms, activation points 955 ± 421) were successfully ablated using LAT Hybrid guided ablation with manual editing in a small number of points. At 6 months, 14 (93%) of the patients were free of AT recurrences. Unedited LAT Hybrid maps showed the highest accuracy in defining the tachycardia mechanism (LAT Hybrid : 49% vs. LAT Peak : 27% vs. LAT Slope : 28%, P < 0.001) and ablation target (LAT Hybrid : 65% vs. LAT Peak : 39% vs. LAT Slope : 31%, P < 0.001). Overall, LAT Hybrid ‐annotated maps were graded as “easier to interpret” by the experts (difficulty score 2.3 ± 0.9) versus LAT Peak (2.8 ± 1) and LAT Slope (3.2 ± 0.8) (P < 0.001). Only 12% of the LAT Hybrid maps were annotated as uninterpretable compared to 31% of LAT Slope and 45% of the LAT Peak maps (P < 0.001). Conclusion Automated LAT Hybrid annotation allows better and easier recognition of the tachycardia mechanism compared to automated LAT Peak and LAT Slope algorithms, although fully automated mapping still requires further improvements.