Heart rhythm | 2019
Are wall thickness channels defined by computed tomography predictive of isthmuses of post-infarction ventricular tachycardia?
Abstract
BACKGROUND\nWall thickness in post-MI scar is heterogenous, with channels of relatively preserved thickness bordered by thinner scar.\n\n\nOBJECTIVE\nThis study sought to determine whether 3D-reconstructed CT-channels correlate with electrophysiological isthmuses during VT.\n\n\nMETHODS\nWe retrospectively studied 9 post-infarction patients (age 57±15 yrs, 1 female) with 10 complete VT activation maps (CL 429+/-77ms) created using an high-resolution mapping. 3D-reconstructed wall thickness maps from CT were merged with the activation map during sinus rhythm (SR) and VT. The relationship between WT and electrophysiological characteristics was analyzed.\n\n\nRESULTS\nA total of 41 CT-channels were identified (median 4/pt), of median length 21.2mm (17.3-36.8mm), width 9.0mm(6.7-16.5mm), and area 1.49cm2(1.00-1.75cm2). WT in the channel was significantly thicker in the center than in the edge (median 2.4mm vs 1.5mm, P<0.0001). Of 3163 (2493-5960) mapping points in SR, 382(191-1115) LAVAs were identified. One patient had a maximal proportion of LAVAs in 3-4mm, three patients in 2-3mm, two in 1-2mm, and two in 0-1mm. The VT-isthmuses of all 10 VTs corresponded with one to four CT-channels. Twenty one of the 41 CT-channels (51.2%) corresponded to a VT-isthmus (entrance, mid, or exit). Electrophysiological VT-isthmuses were more likely to be associated with CT-channels that were longer [P=0.04, OR 1.05/mm], thinner (but not less than 1mm) [P=0.03, OR 0.36/mm], or parallel to the mitral annulus [P=0.07, OR3.93].\n\n\nCONCLUSIONS\nVT-isthmuses were always found in CT-channels (100% sensitivity), and half of CT-channels hosted VT-isthmuses (PPV 51%). Longer and thinner (but >1mm) CT-channels were significantly associated with VT-isthmuses.