High-Density Mapping of Ventricular Scar A Comparison of Ventricular Tachycardia (VT) Supporting Channels With Channels That Do Not Support VT

Surviving myocytes within scar may form channels that support ventricular tachycardia (VT) circuits. There are little data on the properties of channels that comprise VT circuits and those that are non-VT supporting channels.In 22 patients with ischemic cardiomyopathy and VT, high-density mapping was performed with the PentaRay catheter and Ensite NavX system during sinus rhythm. A channel was defined as a series of matching pace-maps with a stimulus (S) to QRS time of ?40 ms. Sites were determined to be part of a VT channel if there were matching pace-maps to the VT morphology. This was confirmed with entrainment mapping when possible. Of the 238 channels identified, 57 channels corresponded to an inducible VT. Channels that were part of a VT circuit were more commonly located within dense scar than non-VT channels (97% versus 82%; P=0.036). VT supporting channels were of greater length (mean?SEM, 53?5 versus 33?4 mm), had higher longest S-QRS (130?12 versus 82?12 ms), longer conduction time (103?14 versus 43?13 ms), and slower conduction velocity (0.87?0.23 versus 1.39?0.21 m/s) than non-VT channels (P