Identification of critical isthmus using coherent mapping in patients with scar‐related atrial tachycardia

Introduction Accurate identification of slow conducting regions in patients with scar‐related atrial tachycardia (AT) is difficult using conventional electrogram annotation for cardiac electroanatomic mapping (EAM). Estimating delays between neighboring mapping sites is a potential option for activation map computation. We describe our initial experience with CARTO 3 Coherent Mapping (Biosense Webster Inc,) in the ablation of complex ATs. Methods Twenty patients (58 ± 10 y/o, 15 males) with complex ATs were included. We created three‐dimensional EAMs using CARTO 3 system with CONFIDENSE and a high‐resolution mapping catheter (Biosense Webster Inc). Local activation time and coherent maps were used to aid in the identification of conduction isthmus (CI) and focal origin sites. System‐defined slow or nonconducting zones and CI, defined by concealed entrainment (postpacing interval