Geometric Features of Ventricular Tachycardia Corridors in Patients With Ischemic Cardiomyopathy

BACKGROUND: A 3-dimensional hyperboloid model has been proposed to characterize ventricular tachycardia (VT) circuitry. We sought to characterize the geometric features of viable corridors, derived from late gadolinium enhanced cardiovascular magnetic resonance, that participate in VT circuitry in ischemic cardiomyopathy. METHODS: In this retrospective cohort study, we analyzed patients with ischemic cardiomyopathy who underwent cardiovascular magnetic resonance before their first VT ablation between November 2018 and May 2024. Viable corridors traversing infarct tissue on late gadolinium enhanced images were coregistered with VT corridor entrance and exit site coordinates, identified by entrainment/pace mapping. The prevalence of VT corridor geometry (hyperboloid, funnel, or cylinder) and corridor ostium angle, width, length, thickness, volume, and accessibility from chambers accessed during the procedure were measured. RESULTS: The cohort included 46 patients (95.4% male; 68±8 years of age). Of 125 VT exit sites that registered to a corridor ostium among 45 patients, central corridors predominantly exhibited hyperbola geometry (93.6%), with 4.8% exhibiting funnel and 1.6% exhibiting cylinder geometry. Of 11 VT entrance sites that registered to a corridor ostium among 5 patients, all central corridors exhibited hyperbola geometry. The mean angle of corridor ostium at VT exit was significantly larger than the angle of the opposite ostium (mean±SD, 102.8°±34.1° versus 83.2°±29.5°; P < 0.001). CONCLUSIONS: Most VT corridors in patients with ischemic cardiomyopathy, derived from late gadolinium enhanced magnetic resonance images and validated by mapping, were hyperboloid, but funnel and cylinder shapes were also seen. The central hyperbola exhibits a larger opening angle at the exit ostium than the entrance.