SMS: Substrate Modification Study in Patients Getting an Implantable Cardioverter Defibrillator (ICD) (SMS)

Inclusion Criteria: Coronary artery disease documented by coronary angiography. For the purpose of this study, coronary artery disease will be defined as the presence of a 50% or more diameter stenosis of the left main or of a 75% or more diameter stenosis of the left anterior descending, circumflex or right coronary arteries, or the history of a surgical or percutaneous revascularization procedure. Left ventricular ejection fraction < 40% as estimated by echocardiography or contrast ventriculography within the previous 30 days. Clinical unstable VT without reversible factors (acute ischemia or antiarrhythmic medications as defined below). Unstable VT can have one of the following clinical presentations: Hypotensive VT without major neurologic dysfunction; Syncope; or Cardiac arrest. Exclusion Criteria: Age < 18 years or > 80 years Protruding left ventricular (LV) thrombus on pre-ablation echocardiogram Acute myocardial infarction within the preceding 2 months Class IV New York Heart Association (NYHA) heart failure Valvular heart disease or mechanical heart valve precluding access to the left ventricle Unstable angina Cardiac surgery within the past 2 months Serum creatinine > 220 mmol/L (2.5 mg/dL) Thrombocytopenia or coagulopathy Contraindication to heparin Pregnancy Acute illness or active systemic infection Other disease process likely to limit survival to less than 12 months Significant medical problem that, in the opinion of the principal investigator, would preclude enrollment into the study Participation in another investigational study Unwillingness to participate or lack of availability for follow-up