Sun Huan,Lakin Robert,Yang Ping, et al. Letter by Sun et al Regarding Article, "Electrogram Analysis and Pacing Are Complimentary for Recognition of Abnormal Conduction and Far-Field Potentials During Substrate Mapping of Infarct-Related Ventricular Tachycardia" [J].CIRCULATION-ARRHYTHMIA AND ELECTROPHYSIOLOGY,2015,8(6):1520-1520.