LAUSR

BACKGROUND Wall thickness in post-MI scar is heterogenous, with channels of relatively preserved thickness bordered by thinner scar. OBJECTIVE This study sought to determine whether 3D-reconstructed CT-channels correlate with electrophysiological isthmuses during VT. METHODS We 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. RESULTS A 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]. CONCLUSIONS VT-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.