The purpose of this registry study is to confirm the long-term safety and reliability of the Plexa lead used with a BIOTRONIK ICD or CRT-D. The treatment you will be receiving is standard of care. The only research activity is collecting data related to this standard of care. The study sponsor, BIOTRONIK, will collect long-term data on the Plexa lead, your ICD or CRT-D and your health status. The study involves collection and review of data at regular follow-up visits with your doctor. These follow-up visits with your doctor are no different than would otherwise occur if you did not enroll in this study.The BIOTRONIK Plexa lead is legally marketed in the United States and is not an investigational product. Your participation in this study is expected to last 5 years.