Substrate-based DEEP mapping and activation mapping are two of the main techniques used for guiding ventricular tachycardia (VT) ablation. There is no data comparing directly the extent of applicability, procedural results, and the long-term outcomes between the two mapping strategies.This randomized clinical trial aims to test whether activation mapping is superior to DEEP mapping to reduce ventricular tachycardia recurrence.

The primary endpoint of the study is to compare recurrence-free survival rate of ventricular tachycardia at 12 months and procedural feasibility of substrate-based DEEP mapping versus activation mapping for VT ablation.

Inclusion Criteria:

• Patients with an implanted ICD (all brands)
• Patients with the indication for Ventricular Tachycardia Ablation (both first and redo procedures), supported by EnSite 3D mapping system, for the following disease aetiologies: previous MI, myocarditis, arrhythmogenic right/left ventricular dysplasia
• Age: 18 years or more.
• A participant is willing and able to give informed consent for participation in the trial and is available to respect the assessments described in the protocol and informed consent form.

Exclusion Criteria:

• Contraindication to anticoagulants.
• Presence of thrombi.
• Presence of Mitral and Aortic prosthetic valve.
• Recent (less than 3 months) myocardial infarction, unstable angina, or Coronary Artery Bypass.
• Ventricular Tachycardia caused by reversible pathology.
• Life expectancy less than 1 year, according to the investigator.
• Contraindications to the use of ablation/diagnostic catheters or to cardiac catheterization.
• Female participant who is pregnant, lactating, or planning pregnancy during the course of the trial.