Right heart failure (RHF) remains an important adverse event following durable LVAD support. Furthermore, delayed institution of mechanical support for RHF has been associated with poor survival outcomes. On the other hand, multiple forms of biventricular mechanical support including total artificial heart (TAH) replacement appear to be associated with greater mortality and morbidity relative to isolated LVAD support. Thus, there is an important need to accurately predict how the circulation will respond to isolated LVAD support and when additional right-sided mechanical support is warranted. In this chapter, we describe a variety of pre-implant clinical features, hemodynamic measurements, echocardiographic parameters, and risk models which may aid in this important prediction.