Population
This study included all consecutive patients with drug-resistant VT undergoing catheter ablation in two different institutions, between January 2008 and July 2019. Only patients with scar-related VT etiology of either IHD or NICM etiology were included, and no Chagas disease patient was included in this analysis. ES was defined as the occurrence of ≥3 episodes of VT or ventricular fibrillation during a 24-h period resulting in an appropriate ICD therapy.