Primary Outcome Measures:
- sudden cardiac death [ Time Frame: 6 month intervals ]
- cardiovascular death [ Time Frame: 6 month intervals ]
- appropriate ICD discharge [ Time Frame: 6 month intervals ]
- composite sudden cardiac death and appropriate ICD discharge [ Time Frame: 6 month intervals ]
Secondary Outcome Measures:
- heart failure admission [ Time Frame: 6 month intervals ]
Some people with heart disease and a weak heart muscle experience abnormal electrical activity of the heart that may predispose them to sudden death. In light of this risk, it has been recommended that such patients undergo implantation of an implantable cardioverter defibrillator (ICD). Your doctors have determined that you are such a patient and are to undergo implantation of an ICD. It is unclear who among the many patients who undergo ICD implantation for this reason are at greatest risk of sudden death and therefore require electrical response from their ICD. This research is being done to determine whether new imaging tests, such as magnetic resonance imaging (MRI) or multi-detector computed tomography (MDCT), can be used to predict who is at highest risk of sudden death and require electrical response from their ICD.