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

High-density automated mapping of regular atrial tachycardias (ATs) requires accurate assessment of local activation times (LATs).

To evaluate high-density mapping of ATs and compare the accuracy of different automated LAT annotation algorithms.

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.

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).

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.