Target enrollment is up to 100 patients at 15 U.S. sites. Patients will be enrolled within a period of 12 to 15 months. Based on the follow-up period of 6 months per patient, the study duration is 18 to 21 months from the date of first patient enrollment. All patients will give written informed consent prior to enrollment and will be implanted with the legally marketed BIOTRONIK Kronos LV-T, or an appropriate BIOTRONIK CRT-D, as well as legally marketed pacing and defibrillation leads. In addition, all patients will be receiving a legally marketed external telemonitoring system to determine weight and blood pressure at home.