Bridging anatomy and function in ischemic VT: CT wall-thickness and coherent mapping insights

Abstract

Background Functional mapping tools such as Coherent Mapping (CM) and Isochronal Late Activation Mapping (ILAM) allow visualization of conduction slowing and block during ventricular tachycardia (VT) ablation; however, their anatomical correlates within computed tomography (CT)-derived myocardial wall-thickness (WT) maps are incompletely defined. We aimed to evaluate the spatial relationship between CT-derived WT characteristics and functional electroanatomical markers and to assess the predictive value of WT-derived conduction channels (WTC) for identifying critical VT isthmuses. Methods Seven consecutive patients with ischemic cardiomyopathy undergoing VT ablation and pre-procedural contrast-enhanced CT were analyzed. WT maps and WTCs were reconstructed using the inHeart (TM) platform and integrated with CARTO 3 electroanatomical maps. CM-SCZs, ILAM-DZs, and lines of blocks (LOBs) were identified using predefined criteria and projected onto WT models. Local WT values, overlap with WT <= 5 mm regions, and Dice similarity coefficients were calculated to quantify anatomical-functional concordance. Results Eighteen CM-SCZs, 15 ILAM-DZs, and 12 LOBs were identified. Functional regions predominantly localized within thinned myocardium (WT <= 5 mm). Mean WT was 3.6 +/- 0.8 mm for SCZs, 3.8 +/- 0.9 mm for DZs, and 4.2 +/- 1.1 mm for LOBs, compared with 6.3 +/- 1.3 mm in remote myocardium (p < 0.01). SCZs overlapped with WT <= 5 mm areas by 74 +/- 12% (Dice 0.67 +/- 0.10), while DZs showed 70 +/- 15% overlap (Dice 0.63 +/- 0.11). Direct correspondence between WTCs and SCZs occurred in 50% of cases. Conclusions Although CT-derived WTCs identify regions at risk, functional mapping remains essential for precise substrate delineation. Integrated CT and CM/ILAM analysis may enhance targeting efficiency during VT ablation.