The SoundScar Study The SOUNDSCAR Study

ICE imaging during VT ablation is currently largely used for definition of cardiac anatomy. The role of the technique to specifically define scar and arrhythmogenic substrate has not been systematically evaluated. The aim is to assess the efficacy of the technique to accurately define the arrhythmogenic substrate.

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)