The ASSURE Study will evaluate shock conversion performance when programming the first shock of an implantable cardioverter-defibrillation (ICD) is based on an implant test consisting of either 1) a single induction of ventricular fibrillation (VF) and subsequent demonstration conversion success at 14 J or 2) an upper limit of vulnerability (ULV) test at 14 J.

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