Ovatio DR and VR Implantable Cardioverter Defibrillators Post-approval Study

Inclusion Criteria: * Candidates will come from the investigator's general ICD population who meet any of the accepted indications for an ICD implant according to the "ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death" (Zipes et al., JACC Vol. 48, No. 5, Sept. 2006:1064-1108). Exclusion Criteria: * Ventricular tachyarrhythmia that may have transient or reversible causes such as: acute myocardial infarction, digitalis intoxication, drowning, electrocution, electrolyte imbalance, hypoxia, sepsis, or unstable ischemic episodes * Incessant tachyarrhythmia * Implanted pacemaker * Primary disorder of bradyarrhythmia or atrial tachyarrhythmia * Of minor age * Pregnant * Participating in another clinical study