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Figure 1 Substrate mapping and radiofrequency (RF) ablation in Patient #7. The scale ranges from 0.5 to 1.5 mV in the bipolar voltage map. Purple represents normal tissue, and red represents highly scarred tissue. The localized postero-basal infarction is seen in the postero-anterior view in the bipolar voltage map. The morphologies of the two major induced ventricular tachycardia (VTs) as well as the corresponding pace-mapping sites, are shown (arrows point to sites of stimulation). Pacing between these two sites (red dot) generated a QRS morphology that alternated between VT-1 and VT-2, but with a longer stimulus-QRS latency time. This site likely represented a common pathway for the two VT circuits and was incorporated in the ablation strategy (a geometry/mesh map is shown on the bottom right). No VT was inducible postablation. Each red dot represents a 1-min RF application.