Structural and Functional Characteristics of Cardiac MRI‐Detected Corridors in Ischemic Ventricular Tachycardia

BACKGROUND: Cardiac magnetic resonance imaging (CMRI) could identify potential critical substrate having role in the development of ventricular tachycardia (VT). This study aimed to evaluate the correlation between corridors identified using software based analysis of late- gadolinium enhanced CMRI (ADAS-3D) and electroanatomical mapping (EAM) findings as well as predictors of arrhythmogenicity and clinical outcomes. METHODS: We retrospectively analyzed a total of 43 consecutive patients who underwent ischemic VT ablation with pre-procedural ADAS 3D CMRI analysis. Substrate mapping including functional evaluation via isochronal late activation mapping (ILAM) was performed in every patient. The correlation between corridor morphometric parameters and electroanatomic mapping findings were analyzed. RESULTS: Among 89 identified CMRI corridors, 57.3% were related to deceleration zones (DZs) during ILAM. DZ-related corridors demonstrated greater length (72.6 vs. 32.2 mm, p < 0.001), border zone mass, and protected volume (p < 0.001) compared to DZ-unrelated corridors. In 30/43 patients with inducible VT, 54.4% of the CMRI-detected corridors were VT-isthmus related. Multivariable analysis revealed that corridor length was the strongest independent predictor of arrhythmogenicity (OR = 1.032, 95% CI:1.012-1.054, p < 0.001 for DZ and OR = 1.025, 95% CI:1.002-1.049, p = 0.033 for VT). In patients with inducible VT, CMRI-detected corridors demonstrated most commonly transmural / partial transmural (40.5%) involvement, with complete endocardial visualization of VT circuit in only 20% of VTs. At a 14-month follow-up with a recurrence rate of 18.6%, epicardial BZ+scar percentage was associated with VT recurrence, in an exploratory univariable analysis (HR = 1.058, 95% CI: 1.002-1.117, p = 0.042). CONCLUSIONS: ADAS 3D analysis revealed the 3-D complexity of VT corridors in ischemic cardiomyopathy, predominantly having non-endocardial distribution.