PAM-VT 2 Study: Long-Term Scar Evolution and Ablation Lesion Assessment by Late Gadolinium Enhancement Cardiac Magnetic Resonance After Ventricular Tachycardia Ablation

BACKGROUND: Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is useful for identifying ventricular tachycardia (VT) substrate in patients with structural heart disease. While preprocedural LGE-CMR is widely used for planning, the role of postprocedural LGE-CMR in evaluating VT ablation success and long-term scar evolution has been less explored. This study aimed to prospectively and systematically assess the long-term evolution of scar and ablation lesions using serial postablation LGE-CMR with long-term follow-up. METHODS: This prospective study included 51 patients (mean age, 65.2±9.8 years; men, 95.8%; ischemic heart disease, 83%; left ventricular ejection fraction, 34.5±10.4%) undergoing their first substrate-based VT ablation between March 2019 and July 2020. Preprocedural LGE-CMR and 2 postprocedural scans at 3 to 6 months (CMR-1) and 18 to 24 months (CMR-2) were performed. Scar characteristics, including core scar, border zone, and conducting channels, were analyzed. VT recurrence was monitored, and factors associated with recurrence were evaluated using a Cox proportional hazards model. A Kaplan-Meier curve was used to represent the VT-free survival function. RESULTS: Core scar mass increased significantly from baseline to CMR-1 (12.2±1.5 to 19.8±1.6 g, P