Paced Electrogram Feature Analysis (PEFA) for Ablation Targeting in Ischaemic Ventricular Tachycardia

Inclusion Criteria: * greater than 18 years of age * Ischaemic heart disease and prior myocardial infarction (using the international definition of MI: Q waves or imaging evidence of regional myocardial akinesis/thinning in the absence of a non-ischemic cause with documentation of prior ischaemic injury) * Eligible for catheter ablation as standard of care * Implantable Cardioverter Defibrillator Exclusion Criteria: * Unable or unwilling to provide consent * Both mechanical aortic and mitral valve * LV thrombus, * NYHA class IV heart failure symptoms * Contraindication to heparin * Survival limited to \<1 year in estimation of attending care team, * Prior VT ablation Exclusion to standard of care VT catheter ablation procedure such as * Active ischaemia (acute thrombus diagnosed by coronary angiography, or dynamic ST segment changes demonstrated on ECG) or another reversible cause of VT (e.g. drug- induced arrhythmia), had recent acute coronary syndrome within 30 days thought to be due to acute coronary arterial thrombosis, or have CCS functional class IV angina. Note that biomarker level elevation alone after ventricular arrhythmias does not denote acute coronary syndrome or active ischemia. * Non-ischaemic cardiomyopathy because of reduced ablation success and PEFA has not been examined in the context of a non-ischaemic cardiomyopathy