The primary objective of the SynCardia temporary Total Artificial Heart (TAH-t) for DT Study is to evaluate whether the TAH-t can support patients with life-threatening irreversible biventricular heart failure who are ineligible for cardiac transplantation (as determined by the implanting center at time of implant screening assessment), without experiencing permanent disabling stroke-related deficits (as evidenced by a Modified Rankin Scale score of 0 - 2). The other primary objective of the study is to evaluate whether the safety profile of the device, when used for DT, is acceptable.