This study is a multi-center, prospective, non-randomized, 5-year data collection registry. Eligible patients must have been successfully implanted with a Linox Lead System connected to a BIOTRONIK ICD and consented and enrolled between 1-45 days following implant. This study is designed to be a post-implant (office-based) registry, and patients are meant to be seen according to each institution's standard of care, but not to exceed a follow-up time frame of every 6 months. At least 2000 patients will be enrolled in this registry, and each patient will be followed for five years post-implant.