Temporal and spatial pacemap parameters for identification of cardiac surfaces with critical sites for ventricular tachycardia

Introduction Multisurface pacemapping may help identify the surface of interest in scar‐related ventricular tachycardia (VT). This study aimed to investigate the performance of pacemap parameters for detecting critical sites through multisurface mapping. Methods and Results In 26 patients who underwent scar‐related VT ablation, pacemap parameters including a matching score, the difference between the longest and shortest stimulus‐QRS intervals (Δs‐QRS), and the distance between the good pacemap sites were measured. The parameters were compared between surfaces with and without critical sites and ablation outcomes. A total of 941 pacemap at 56 surfaces targeting 35 VTs were analyzed. A greater Δs‐QRS (40 vs. 8 ms, p 19 mm showed high positive likelihood ratios (19.8 and 6.1, respectively) for discriminating the surface harboring the critical site. Ablation of VTs fulfilling these parameters was successful on the surfaces, but without the required multisurface ablation. Conclusion Temporal (Δs‐QRS) and spatial (distance) parameters for good pacemap match sites were excellent markers for detecting the surface harboring critical sites in scar‐related VT. A multisurface pacemapping can successfully identify the surface of interest. Pacemap conducted on the surfaces harboring isthmus demonstrate sites showing good pacemap scores with a long and a short pacing latency (temporal distribtion), in a separate location (spatial distribution), enabling to delineate the putataive isthmus, regardless of whether the entire circuit is on the surface or not. Pacemapping conducted on the surfaces not harboring isthmus demonstrate only modest pacemap scores, surrounded by poorer score.