Inclusion Criteria:  Ventricular tachycardia ablation between October 2014 and April 2021 Patient for whom electroanatomical data are available. Ischemic cardiomyopathy / previous myocardial infarction At least 30 points of pace-mapping during the VT procedure  Exclusion Criteria:  Incomplete data Poor quality ECG recordings Absence of ventricular tachycardia isthmus identified during the procedure