Inclusion Criteria:  • Patients with structural heart disease; previous myocardial infarction, left ventricular dilatation/systolic dysfunction, or normal left ventricular diameters/ systolic function with evidence of ventricular scar on contrast enhanced-cardiac magnetic resonance or electroanatomic map.  Sustained monomorphic ventricular tachycardia documented by 12-lead ECG or implantable cardioverter defibrillator (electrograms resistant to antiarrhythmic drug treatment or requiring implantable cardioverter defibrillator therapies.  Exclusion Criteria:  • Patients with ventricular arrhythmias attributed to reversible causes.