ASSURE Study - Arrhythmia Single Shock DFT Versus ULV: Risk Reduction Evaluation With ICD Implantations

Inclusion Criteria: Patients who meet current indications for an ICD including cardiac resynchronization therapy (CRT) devices Patients who sign and date a Patient Informed Consent form prior to the implant visit Patients who remain in the clinical care of the enrolling physician in approved centers Patients who receive only left-sided pectoral implantations with the ICD lead placed in the right ventricular apex Patients who have a minimum R wave of at least 7 mV; or for ICD replacement, patients who have a minimum chronic R wave of at least 5 mV Exclusion Criteria: Patients who are involved in Non-Invasive Programming Stimulation (NIPS) studies Patients who undergo lead repositioning Patients who are expected to receive a heart transplant during the duration of the study Patients who have or who are likely to receive a tricuspid valve prosthesis Patients who are currently enrolled in another investigational study or registry that would directly impact the treatment or outcome of the current study Patients who are younger than 18 years of age Patients who are pregnant or plan to become pregnant during the study Patients whose life expectancy is less than 12 months Patients who are mentally incompetent and cannot sign a Patient Informed Consent form or comply with the study