INTRODUCTION
Patients with ischemic (IHD) and nonischemic (NICM) dilated heart disease and reduced left ventricular ejection fraction are at increased risk of ventricular tachycardias (VTs) or sudden cardiac death1. Implantable cardioverter-defibrillators (ICDs) are indicated in these patients and have shown to reduce mortality1. However, some studies suggest that ICD shocks reduce the quality of life and may be linked to increased mortality, particularly after an electrical storm (ES)2. VT catheter ablation is an invasive treatment modality for antiarrhythmic drugs-resistant VT that reduces arrhythmic episodes, improves quality of life and improves survival in patients with ES3. Current guidelines for VT ablation3 recommend epicardial catheter ablation for NICM patients after a first failed endocardial catheter ablation or as first intention when there is a suspicion of an epicardial circuit. Epicardial ablation role is not as established in the IHD population, although some studies show potential VT-free survival improvement after a combined endo-epicardial approach (C-ABL)4. However, complex arrhythmia substrates and potential life-threating procedure complications increase the technical difficulty of the epicardial catheter ablation5. Direct comparisons of combined and non-combined endo-epicardial ablations outcomes are limited by patient characteristics, follow-up duration, protocols heterogeneity and scarcity of randomized trials4,5. We aim to investigate the long-term clinical outcomes of these 2 strategies in the IHD and NICM populations. To overcome said limitations, a propensity score-matched sensitivity analysis was performed.