Ventricular assist devices are an important therapeutic option for advanced congestive heart failure. A left ventricular assist device (LVAD) can be implanted as a bridge to transplantation or for the purpose of destination therapy. LVADs improve end-organ function and reduce morbidity and mortality in appropriately selected patients. The development of axial flow pumps has overcome many of the limitations of the first-generation pulsatile flow LVADs. However, many complications of LVAD therapy remain. Treating these complications requires an understanding of LVAD physiology. Ongoing research is directed at reducing the incidence of many of these complications and may allow for wider use of LVADs.