The SoundScar Study The SOUNDSCAR Study

Inclusion Criteria: * Prior heart attack (myocardial infarction) with evidence from prior non-invasive imaging demonstrating regions of the heart with reduced heart muscle function (myocardial hypokinesia/akinesia/thinning) in the absence of a non-heart attack-related (non-ischaemic) cause * Age over 18 years * One of the following abnormal heart rhythm (VT) events within last 6 months: * ≥3 episodes of VT treated with therapeutic rapid pacing from an implantable cardiac defibrillator (antitachycardia pacing \[ATP\]) * ≥1 appropriate shocks from an implantable cardiac defibrillator * ≥3 episodes of abnormal heart rhythm (VT) within 24 hours * Sustained VT below the detection rate of the implantable cardiac defibrillator (documented by ECG/cardiac monitor) * Sustained abnormal heart rhythm (VT) in the absence of ICD which is documented by ECG/cardiac monitor * Patients in whom ICE imaging is planned for the clinical VT ablation procedure (clinical indication) Exclusion Criteria: * Patient unable or unwilling to provide informed consent. * Acute heart attack (acute coronary syndrome with acute thrombus diagnosed by coronary angiography, or dynamic ST segment changes demonstrated on ECG) or another reversible cause of abnormal heart rhythm (VT) - e.g. electrolyte abnormalities or drug-induced abnormal heart rhythms * Ineligible for ablation (known to have protruding clot in the chamber of interest (left ventricular thrombus), or have implanted mechanical aortic and mitral valves) * Had recent coronary bypass surgery (\< 3 months) or percutaneous coronary intervention (\<3 months) * Pregnant patients (pregnancy test will be performed in patients who are of childbearing age who are not on an effective contraceptive prior to all VT ablation procedures) * Had recent coronary bypass surgery (\< 3 months) or percutaneous coronary intervention (\<3 months)