Structural and functional correlates of ventricular tachycardia corridors in ischemic cardiomyopathy: cardiac magnetic resonance imaging and electroanatomic mapping correlation

Abstract Background/Introduction While ischemic VT circuits were traditionally conceptualized as two-dimensional (2D), recent evidence suggests a complex three-dimensional (3D) architecture. This study aimed to correlate the 3D morphometric characteristics of pixel signal intensity based 3D CMR analysis (PSI-3D CMR)-defined corridors with functional electroanatomic mapping (EAM) findings and clinical outcomes. Purpose To evaluate the specific characteristics and anatomical distribution of CMR-detected VT corridors, their relationship with functional substrate (Deceleration Zones, Late Potentials), and critical isthmuses identified by EAM, and to determine predictors of VT recurrence. Methods Forty-three consecutive ICM patients undergoing VT ablation (January 2021–2025) with pre-procedural PSI-3D CMR analysis were retrospectively analyzed. PSI-3D CMR analysis defined transmural layers by dividing the left ventricular wall thickness into 9 concentric layers: 10–30% endocardial, 40–60% mid-myocardial, and 70–90% epicardial. Corridor morphometric parameters (length, border zone (BZ) mass, protected volume, protected length and width), number of involved AHA segments, and transmural layer count were compared with EAM findings. Arrhythmogenic corridors were defined that VT components in patients with activation mapping or DZ in patients without inducible VT. Results A total of 89 corridors were identified, with 57.3% (n=51) being DZ-related. DZ-related corridors exhibited significantly greater length (72.6 ± 50.4 mm vs 32.2 ± 24.8 mm, p 0.001), higher BZ mass (3.27 ± 2.37 g vs 1.42 ± 1.54 g, p 0.001), protected volume (158.8 ± 163.9 mm³ vs 55.3 ± 66.7 mm³, p 0.001), and protected length (23.9 ± 19.7 mm vs 12.2 ± 10.0 mm, p = 0.001). Mean width did not differ significantly. In multivariate logistic regression, corridor length remained as the sole independent predictor of DZ-related corridors (OR = 1.034, p 0.001) (Table-1). In the 30 patients with inducible VT, 68 corridors were correlated with EAM findings; 54.4% (n=37) were VT isthmus-related. 71.8% of all corridors contained non-endocardial components, with distribution including mid-myocardial/epicardial (51.3%) and transmural (20.5%) involvement. Activation mapping confirmed only 12.1% of VT circuits showed complete endocardial visualization of entrance-isthmus-exit (χ² = 21.948, p = 0.001) (Table-2). At a median 14-month follow-up, VT recurrence occurred in 18.6% of patients. Epicardial BZ+scar percentage emerged independent predictor of VT recurrence (HR = 1.039, 95% CI: 1.002–1.079, p = 0.042). Conclusion This comprehensive analysis reveals that VT corridors in ischemic cardiomyopathy predominantly exhibit complex three-dimensional architecture extending beyond the endocardial surface.ADAS 3D Corridors Morphometric CharacterRelationship Between ADAS 3D Anatomic Co